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Last modified: Tue Apr 4 10:50:24 2017.


List of Routines


Routine Descriptions

CAT_STRUCT

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 NAME:
        CAT_STRUCT

 PURPOSE: 
        Concatenate all tags within 2 or more structures. 
        Return one structure with the same tags as each individual 
        structure.

 CATEGORY:
        Structures

 CALLING SEQUENCE:
        RESULT = CAT_STRUCT( STR1, STR2, STR3, STR4, STR5 )

 INPUTS:
        STR1, STR2, STR3, STR4, STR5 -> Structures to concatenate

 KEYWORD PARAMETERS:
        None

 OUTPUTS:
        RESULT -> The concatenated structure

 SUBROUTINES:
        None

 REQUIREMENTS:
        None

 NOTES:
        The user can concatenate as many structures as desired by
        adding extra input arguments: st6, st7, st8, etc.

 EXAMPLE:
         a = {Name: 'Larry', Age: 46}
         b = {Name: 'Chuck', Age: 10}
         c = {Name: 'Alice', Age: 35}

         d = cat_struct( a, b, c )
         print, d.Name


 MODIFICATION HISTORY:
        cdh, 08 Jul 2010: GAMAP VERSION 2.15
                          - Initial version

(See /n/home09/ryantosca/IDL/gamap2/structures/cat_struct.pro)


CHKSTRU (FUNCTION)

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 NAME:
        CHKSTRU  (function)

 PURPOSE:
        Check validity of a structure and test if necessary
        fields are contained

 CATEGORY:
        Structures

 CALLING SEQUENCE:
        RESULT = CHKSTRU( STRUCTURE, [ FIELDS, Keywords ] ) 

 INPUTS:
        STRUCTURE -> the structure to be tested.  If STRUCTURE is
             not of type structure, the function will return 0

        FIELDS (optional) -> a string or string array with field 
             names to be contained in STRUCTURE.  CHKSTRU returns 
             1 (true) only if all field names are contained in 
             STRUCTURE.  The entries of FIELDS may be upper or 
             lowercase.

 KEYWORD PARAMETERS:
        INDEX -> a named variable that will contain the indices of
             the required field names in the structure. They can then
             be assessed through structure.(index(i)) . Index will
             contain -1 for all fields entries that are not in the
             structure.

        /VERBOSE -> set this keyword to return an error message 
             in case of an error.

 OUTPUTS:
        RESULT -> Returns 1 if successful, otherwise 0.

 SUBROUTINES:
        None

 REQUIREMENTS:
        None

 NOTES:
        None

 EXAMPLES:
        (1)
        TEST     = { a:1, b:2, c:3 }
        IF CHKSTRU( TEST ) THEN PRINT, 'TEST is a structure!'
          TEST is a structure!

             ; Verify that TEST is a structure rather than
             ; a scalar or an array variable. 

        (2)
        TEST     = { a:1, b:2, c:3 }
        REQUIRED = [ 'a', 'c' ]
        IF CHKSTRU( TEST, REQUIRED ) THEN PRINT, 'Found a and c.'
          Found a and c.

             ; MAKES sure that structure TEST contains
             ; the tag names A and C.

 MODIFICATION HISTORY:
        mgs, 02 Mar 1998: VERSION 1.00
        mgs, 07 Apr 1998: - second parameter (FIELDS) now optional
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10
                          - Updated documentation

(See /n/home09/ryantosca/IDL/gamap2/structures/chkstru.pro)


CHOICE

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 NAME:
        CHOICE

 PURPOSE:
        Allows user to choose interactively from several options.

 CATEGORY:
        General

 CALLING SEQUENCE:
        RESULT = CHOICE( VALUES [,options] )

 INPUTS:
        VALUES  -> a string array containing the selectable options

 KEYWORD PARAMETERS:
        TITLE -> title to be displayed on top of the selection menu

        DEFAULT -> a default selection (to allow user to simply 
             press enter)

        BY_INDEX  -> return selection index rather than value

        /NOABORT -> prevents addition of 'ABORT' to selection

 OUTPUTS:
        CHOICE returns a string containing the selected value or
            the index of the selection if keyword /BY_INDEX is set.

 SUBROUTINES:
        None

 REQUIREMENTS:
        None

 NOTES:
        CHOICE automatically adds 'ABORT' to the list of selections.
        If keyword BY_INDEX is set then ABORT will return -1
        (unless /NOABORT keyword is set)

 EXAMPLE:
        DIRNAMES = [ '~my/dir/','~your/dir/','~any/dir']
        DIR      = CHOICE( DIRNAMES, TITLE='Select Directory' )

        IF (DIR ne 'ABORT') THEN BEGIN
            OPENR, U1, DIR+FILE, /GET_LUN
            READF, U1, DATA
            CLOSE, U1
            FREE_LUN,U1
        ENDIF ELSE PRINT,'ABORTED !'

             ; Allow user to pick a directory and then
             ; read a file from that directory.

 MODIFICATION HISTORY:
        mgs, 26 Sep 1997: VERSION 1.00
        mgs, 17 Nov 1998: - added DEFAULT and NOABORT keywords
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10

(See /n/home09/ryantosca/IDL/gamap2/general/choice.pro)


CINDEX

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 NAME:		
        CINDEX

 PURPOSE:	
        This is a program for viewing the current colors in the 
	 colortable with their index numbers overlayed on each color.
        
	 CINDEX Draws a NROW x NCOL set of small rectangles, each of 
        which displays one of the colors in the color table.  It also
        writes the color index number on top of each rectangle.

 CATEGORY:	
        Color

 CALLING SEQUENCE:	
        CINDEX

 INPUTS:	
        None
	
 KEYWORD PARAMETERS:
        NCOL -> Specify the number of columns in the plot. 
             Default is 16.

        NROW -> Specify the number of columns in the plot.  If not 
             specified, then CINDEX will compute the minimum number
             of rows that are needed to display all of the colors,
             given the setting of NCOL.

        TITLE -> Specify the title for the plot window.

        /ALL -> Set this switch to plot all 256 colors on a 16x16 grid.
             Colors that are not defined will be rendered as white.

 OUTPUTS:	
        None

 SUBROUTINES:
        None

 REQUIREMENTS:
        None

 NOTES:
        None

 EXAMPLES:
        (1)
        MYCT, /WhGrYlRd
        CINDEX
 
             ; Displays the colors of the MYCT color table
             ; WHITE-GREEN-YELLOW-RED (spectral).  The drawing
             ; colors and all 20 colors of this table are shown.

        (2)
        MYCT, /WhGrYlRd
        CINDEX, /ALL
 
             ; Same as above, but plots the colors on a 
             ; 16 x 16 grid.

 MODIFICATION HISTORY:  
        INITIAL REVISION: David Fanning, RSI, May 1995
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10
                          - Added NCOL, ROW, TITLE, ALL keywords to
                            allow the user to specify these settings
                            instead of having these be hardwired.
        bmy, 21 Apr 2008: GAMAP VERSION 2.12
                          - Now use NAME and INDEX tags from !MYCT 
                            to define the default title string.

(See /n/home09/ryantosca/IDL/gamap2/color/cindex.pro)


CLOSE_DEVICE

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 NAME:
        CLOSE_DEVICE

 PURPOSE:
        CLOSE_DEVICE closes the PostScript device and spawns
        a print job to the printer specified by the user or
        it can be used to close a graphics window.

 CATEGORY:
        Graphics

 CALLING SEQUENCE:
        CLOSE_DEVICE [,OLD_DEVICE] [, Keywords ]

 INPUTS:
        OLD_DEVICE -> Name of device that shall become the active
             plotting device. If omitted, "X", "WIN" or "MAC" will
             be set depending on !VERSION.OS_FAMILY.  Hence, 
             specification of OLD_DEVICE is only rarely needed.
             This parameter works together with the OLD_DEVICE 
             parameter of OPEN_DEVICE which returns the device name 
             before the postscript device (or a graphics device) is 
             opened.  The OLD_DEVICE parameter can be misused to set 
             the output device to anything! Therefore, it's probably 
             safest to not use it and stick with the operating system 
             dependent default.

 KEYWORD PARAMETERS:
        LABEL -> a string that contains an annotation for a postscript
             plot (usually a user name and/or filename). The current 
             data and time will be appended if TIMESTAMP is set. 
             NOTE: TIMESTAMP will produce an annotation even if LABEL
             is not provided. The annotation is only added to 
             postscript plots and only if the ps file is actually 
             open.

        /TIMESTAMP  -> add date and time to the LABEL on the plot.
             If no LABEL is provided, the username and filename 
             (value of FILENAME will be used or the filename of the 
             current postscript file will be added). The timestamp 
             is only added to postscript plots and only on the last 
             page.

        PRINTER -> Name of the printer queue to send output to.
             Default is 'none', i.e. the postscript file will only 
             be closed and can then be manually printed e.g. using 
             the Unix lpr command.  Direct printing only works in 
             Unix environments.

        WINDOW -> window number to be closed (or -1 if current)

        _EXTRA=e -> any additional keywords to CLOSE_DEVICE will 
             be passed on to STRDATE which is used to format the 
             date and time string.  Possible values are: /SHORT, 
             /SORTABLE, /EUROPEAN.

        LCOLOR -> the color value for the LABEL (default 1).

        LPOSITION -> the position of the LABEL in normalized 
             coordinates (a two-element vector with default 
             [0.98,0.007]).

        LSIZE -> the charcter size of the LABEL (default 0.7).

        LALIGN -> the alignment of the LABEL (default 1).

        FILENAME -> name of the PostScript file.  This is actaully
             obsolete now because the PostScript filename is 
             determined at the time the file is opened (e.g. in
             routine OPEN_DEVICE)

 OUTPUTS:
        If postscript device is active, a *.ps file will be closed 
        and optionally sent to the printer.

 SUBROUTINES:
        External Subroutines Required:
        ================================
        STRDATE (function)

 REQUIREMENTS:
        Requires routines in the 

 NOTES: 
        The WINDOW keyword is only evaluated if the current device 
        supports windows [!D.FLAGS AND 256) GT 0]. If you only want 
        to close a postscript file and don't fuss around with your 
        screen windows then simply don't set this keyword.

 EXAMPLES:
        (1)
        CLOSE_DEVICE

            ; Closes a postscript file (if opened) and resets the 
            ; current plotting device to 'X', 'WIN', or 'MAC' 
            ; depending on the OS_FAMILY.

        (2) 
        CLOSE_DEVICE, PRINTER='hplj4', LABEL='mgs', /TIMESTAMP

            ; If current device name is PS then the postscript 
            ; file will be closed, a user, date and time label will 
            ; be added and the file will be spooled to the printer 
            ; queue 'hplj4'. NOTE: Printing of the file fails if you 
            ; specified FILENAME as a relative path in the OPEN_DEVICE 
            ; command and you changed your working directory while
            ; the device was opened.
  
        (3)
        CLOSE_DEVICE, WIN=-1

            ; If current device name is PS then the postscript file 
            ; will be closed. If the current device is a screen 
            ; device (that supports windows), then the active window
            ;  will be deleted.
 
 MODIFICATION HISTORY:
        bmy, 18 Aug 1997: VERSION 1.00
        bmy, 19 Aug 1997: VERSION 1.01
        mgs, 20 Aug 1997: VERSION 1.02
        mgs, 08 Apr 1998: VERSION 2.00 
                          - automatic filename detection
                          - default device depending on OS_FAMILY
        mgs, 21 May 1998: 
                          - added L.. keywords to control label 
                            and timestamp output
        mgs, 18 Nov 1998:
                          - added output of username as default in timestamp
        bmy, 28 Jul 2000: TOOLS VERSION 1.46
                          - cleaned up a few things
        bmy, 24 May 2007: TOOLS VERSION 2.06
                          - Updated comments
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10

(See /n/home09/ryantosca/IDL/gamap2/graphics/close_device.pro)


CMSET_OP

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 NAME:
   CMSET_OP

 AUTHOR:
   Craig B. Markwardt, NASA/GSFC Code 662, Greenbelt, MD 20770
   craigm@lheamail.gsfc.nasa.gov

 PURPOSE:
   Performs an AND, OR, or XOR operation between two sets

 CATEGORY:
   Math & Units

 CALLING SEQUENCE:
   SET      = CMSET_OP(A, OP, B)

 DESCRIPTION:

   SET_OP performs three common operations between two sets.  The
   three supported functions of OP are:

       OP      Meaning
       'AND' - to find the intersection of A and B;
       'OR'  - to find the union of A and B;
       'XOR' - to find the those elements who are members of A or B 
               but not both;

   Sets as defined here are one dimensional arrays composed of
   numeric or string types.  Comparisons of equality between elements
   are done using the IDL EQ operator.

   The complements of either set can be taken as well, by using the
   NOT1 and NOT2 keywords.  For example, it may be desireable to find
   the elements in A but not B, or B but not A (they are different!).
   The following IDL expressions achieve each of those effects:

      SET = CMSET_OP(A, 'AND', /NOT2, B)   ; A but not B
      SET = CMSET_OP(/NOT1, A, 'AND', B)   ; B but not A

   Note the distinction between NOT1 and NOT2.  NOT1 refers to the
   first set (A) and NOT2 refers to the second (B).  Their ordered
   placement in the calling sequence is entirely optional, but the
   above ordering makes the logical meaning explicit.

   NOT1 and NOT2 can only be set for the 'AND' operator, and never
   simultaneously.  This is because the results of an operation with
   'OR' or 'XOR' and any combination of NOTs -- or with 'AND' and
   both NOTs -- formally cannot produce a defined result.

   The implementation depends on the type of operands.  For integer
   types, a fast technique using HISTOGRAM is used.  However, this
   algorithm becomes inefficient when the dynamic range in the data
   is large.  For those cases, and for other data types, a technique
   based on SORT() is used.  Thus the compute time should scale
   roughly as (A+B)*ALOG(A+B) or better, rather than (A*B) for the
   brute force approach.  For large arrays this is a significant
   benefit.

 INPUTS:

   A, B - the two sets to be operated on.  A one dimensional array of
          either numeric or string type.  A and B must be of the same
          type.  Empty sets are permitted, and are either represented
          as an undefined variable, or by setting EMPTY1 or EMPTY2.

   OP - a string, the operation to be performed.  Must be one of
        'AND', 'OR' or 'XOR' (lower or mixed case is permitted).
        Other operations will cause an error message to be produced.

 KEYWORDS

   NOT1, NOT2 - if set and OP is 'AND', then the complement of A (for
                NOT1) or B (for NOT2) will be used in the operation.
                NOT1 and NOT2 cannot be set simultaneously.

   EMPTY1, EMPTY2 - if set, then A (for EMPTY1) or B (for EMPTY2) are
                    assumed to be the empty set.  The actual values
                    passed as A or B are then ignored.

   INDEX - if set, then return a list of indices instead of the array
           values themselves.  The "slower" set operations are always
           performed in this case.

           The indices refer to the *combined* array [A,B].  To
           clarify, in the following call: I = CMSET_OP(..., /INDEX);
           returned values from 0 to NA-1 refer to A[I], and values
           from NA to NA+NB-1 refer to B[I-NA].

   COUNT - upon return, the number of elements in the result set.
           This is only important when the result set is the empty
           set, in which case COUNT is set to zero.

 RETURNS

   The resulting set as a one-dimensional array.  The set may be
   represented by either an array of data values (default), or an
   array of indices (if INDEX is set).  Duplicate elements, if any,
   are removed, and element order may not be preserved.

   The empty set is represented as a return value of -1L, and COUNT
   is set to zero.  Note that the only way to recognize the empty set
   is to examine COUNT.

 SEE ALSO:

   SET_UTILS.PRO by RSI

 MODIFICATION HISTORY:
   Written, CM, 23 Feb 2000
   Added empty set capability, CM, 25 Feb 2000
   Documentation clarification, CM 02 Mar 2000
   Incompatible but more consistent reworking of EMPTY keywords, CM,
     04 Mar 2000
   Minor documentation clarifications, CM, 26 Mar 2000
   Corrected bug in empty_arg special case, CM 06 Apr 2000
   Add INDEX keyword, CM 31 Jul 2000
   Clarify INDEX keyword documentation, CM 06 Sep 2000
   Made INDEX keyword always force SLOW_SET_OP, CM 06 Sep 2000
   Added CMSET_OP_UNIQ, and ability to select FIRST_UNIQUE or
     LAST_UNIQUE values, CM, 18 Sep 2000
   Removed FIRST_UNIQUE and LAST_UNIQUE, and streamlined
     CMSET_OP_UNIQ until problems with SORT can be understood, CM, 20
     Sep 2000 (thanks to Ben Tupper)
   Still trying to get documentation of INDEX and NOT right, CM, 28
     Sep 2000 (no code changes)
   Correct bug for AND case, when input sets A and B each only have
     one unique value, and the values are equal.  CM, 04 Mar 2004
     (thanks to James B. jbattat at cfa dot harvard dot edu)
   Add support for the cases where the input data types are mixed,
      but still compatible; also, attempt to return the same data
      type that was passed in; CM, 05 Feb 2005
   Fix bug in type checking (thanks to "marit"), CM, 10 Dec 2005
   Work around a stupidity in the built-in IDL HISTOGRAM routine,
      which tries to "help" you by restricting the MIN/MAX to the
      range of the input variable (thanks to Will Maddox), CM, 16 Jan 2006

  $Id: cmset_op.pro,v 1.4 2007/11/20 21:55:32 bmy Exp $

(See /n/home09/ryantosca/IDL/gamap2/math_units/cmset_op.pro)


CODE_TREE

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 NAME:
        CODE_TREE

 PURPOSE:
        This routine produces a tree structure for Fortran programs.
        It will scan a directory for FORTRAN files and gather all
        SUBROUTINE names and CALL statements. FUNCTIONS are not
        parsed.

 CATEGORY:
        General

 CALLING SEQUENCE:
        CODE_TREE [, DEFAULT_PATH, DEFAULT_MAIN ] [ , /FILENAMES ]

 INPUTS:
        DEFAULT_PATH -> the default search path to look for FORTRAN files

        DEFAULT_MAIN -> the default name of the main program file. Note
             that code_tree will not work properly if the main file
             contains subroutine definitions.

 KEYWORD PARAMETERS:
        /FILENAMES -> display the filename where each routine can be
             found together with the routine name.

 OUTPUTS:
        A calling tree is generated on the screen or dumped into a file.

 SUBROUTINES:
        Several

 REQUIREMENTS:
        None

 NOTES:
        None

 EXAMPLE:
        CODE_TREE

 MODIFICATION HISTORY:
       99/5/18 Philip Cameron-Smith, Harvard 
         Initial code.
       99/5/21 Philip Cameron-Smith, Harvard 
         Have included some of my utilities to allow easy distribution.
         Added '1' to names to ensure no future conflicts.
       99/5/24 Philip Cameron-Smith, Harvard 
         Now removes tabs and strings.
         Various other improvements.
       99/5/25 Philip Cameron-Smith, Harvard 
         Reversed order of path and filename arguments
         Converted a "print" to a "printf,lun" to stop lines running
         on when printing to a file.
         Improved check for ENTRY before SUBROUTINE.
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10

(See /n/home09/ryantosca/IDL/gamap2/general/code_tree.pro)


COLORBAR

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 NAME:
        COLORBAR

 PURPOSE:
        Draw a colorbar (legend) with labels

 CATEGORY:
        Color

 CALLING SEQUENCE:
        COLORBAR [ , Keywords ]

 INPUTS:
        None

 KEYWORD PARAMETERS:
        ANNOTATION -> Array with string label values.  If specified,
             ANNOTATION will override the default label values, and 
             will also override the LABEL keyword.

        BOTOUTOFRANGE, TOPOUTOFRANGE -> a color index value for data
             that falls below (or above) the normal plot range. If 
             given, an extra box will be drawn to the left (or right) 
             of the colorbar, and the colorbar will shrink in size.  
             A default label '<' (or '>') will be placed below.  
             NOTE: these options are only available for horizontal 
             colorbars.

        BOR_LABEL, TOR_LABEL -> label values for BOTOUTOFRANGE and 
             TOPOUTOFRANGE that replace the defaults.

        BOTTOM -> First color index to use.  Default is !MYCT.BOTTOM.
             NOTE: In practice you shouldn't have to specify BOTTOM,
             as the value from !MYCT.BOTTOM will reflect the settings
             of the current colortable.

        C_COLORS -> Array of color indices for "discrete" color bars
             e.g. in filled contour plots. You must also use the 
             C_LEVELS keyword, otherwise there will most likely be
             a mismatch between your plot colors and your colorbar 
             colors. COLORBAR normally limits the number of labels
             it prints to 10. Use the SKIP keyword to force a different
             behaviour. If C_COLORS is not undefined it overrides the
             settings from NCOLORS, and BOTTOM.

        C_LEVELS -> Array with label values for "discrete" colorbars.
             Use the LABEL or ANNOTATION keyword for continuous
             colorbars.  C_LEVELS must have the same number of elements 
             as C_COLORS and assigns one label to each color change 
             (LABEL distributes the labels evenly). Use the SKIP
             keyword to skip labels.  As default, COLORBAR limits the 
             number of labels printed to 10.

        AUTOSCALELEVELS -> Set this switch to automatically scale
             labels (specified by C_LEVELS, LABEL, MAX, or MIN) 
             by powers of 10. This reduces the length of each tick label
             and helps prevent overlapping numbers in the colorbar.  

        CHARSIZE -> Specifies the character size for colorbar labels.
             Default is !P.CHARSIZE.

        COLOR -> The drawing color for boxes and labels.  
             Default is !MYCT.BLACK.
 
        DIVISIONS -> Number of labels to put on the colorbar.
             Note that this keyword is overwritten by LABEL.
             The labels will be equally spaced and the /LOG option
             will be honored.

        FLAGVAL -> If set, will place a tick mark with label at a
             user-defined value.  You can use this to denote where
             0 or 1 falls w/in a color range, for example.

        FORMAT -> Output format of the labels.  Default is determined
             according to the range given in min and max.  Label 
             strings will be trimmed, so you can safely specify 
             '(f14.2)' for example.

        LABEL -> Array containing label values (must be numeric).
             Normally, it is easier to generate labels with the 
             DIVISIONS options, but this allows tighter control 
             (e.g. 1,2,5,10,20 labels on logarithmic scales).
             Default (if no DIVISIONS are given): MIN and MAX.
             NOTE: ANNOTATION will 

        /LOG -> Set this switch to invoke logarithmic spacing of 
             labels.  The colors are *always* linearily distributed.

        MAX -> Maximum value to plot.  Default is NCOLORS.

        MIN -> Minimum value to plot.  Default is BOTTOM.

        /NOGAP -> if 0 then there is a gap b/w the triangle or
             rectangle OutOfRange boxes and the bar, else no
             gap. Defalut is to have a gap. If /TRIANGLE and no
             OutOfRange boxes are set then default is No Gap.

        NCOLORS -> Number of colors to use in the colorbar.  Default 
             is !MYCT.NCOLORS.  NOTE: In practice you shouldn't have 
             to specify NCOLORS, as the value from !MYCT.NCOLORS will 
             reflect the settings of the current colortable.

        ORIENTATION -> Specifies the orientation of the colorbar
             labels.  This keyword has the same behavior as the 
             ORIENTATION option in XYOUTS (i.e. ORIENTATION=0 means
             normal "left-right" text, ORIENTATION=-90 means "top-
             bottom" text, etc.)

        POSITION -> A position value or 4-element vector. If POSITION
             contains only one element, it will be centered at the
             bottom or right side of the page and extend over 60% of
             the total plotting area.

        SCIENTIFIC -> If set, will call STRSCI to put the colorbar
             labels in scientific notation format (e.g. in the form
             A x 10^B).  STRSCI will use the format string specified 
             in the FORMAT keyword.

        SKIP -> Print only every Nth discrete label.  The default is 
             computed such that COLORBAR will print no more than 10 
             labels.

        TITLE -> A title string for the colorbar.  (This works similarly 
             to the XTITLE or YTITLE options to the PLOT command.)

        TICKLEN -> A number between 0 and 1 which defines the length
             of the tick marks as a fraction of the size of the plot
             box.  Default is 0.25.

        /TRIANGLE -> to plot triangles at the end of the color bar. If 
             OutOfRange boxes are requested, then the triangles
             replace the rectangle.

        UNIT -> A unit string that will be added to the right of the
             labels.  If /VERTICAL is set, then the unit string will
             be placed at the top of the labels.

        UPOS -> Specifies the position (relative to the size of the 
             colorbar) where the unit string will be placed.  The
             default is 1.15.  To print the unit string closer to the
             end of the colorbar, reduce this value until the desired
             appearance is obtained.

        /VERTICAL -> Set this keyword to produce a vertical colorbar
             (default is horizontal).  Note that out-of-range boxes are
             only implemented for horizontal color bars.  

 OUTPUTS:
        None

 SUBROUTINES:
        External Subroutines Required:
        ====================================
        STRSCI (function)  TRIANGLE

 REQUIREMENTS:
        Assumes that we are using a MYCT-defined colortable.

 NOTES:
        (1) This routine was designed after David Fanning's colorbar
            routine and adapted to our needs.  Some of the postscript
            handling of DF was removed, positioning is a little easier 
            but maybe a little less flexible; out-of-range boxes have 
            been added.

        (2) The !MYCT system variable contains the properties of the
            current MYCT-defined colortable.  You normally should not
            have to explicity pass BOTTOM or NCOLORS, as these
            keywords will be initialized from the values from !MYCT.

 EXAMPLES:
        COLORBAR, MIN=MIN( DATA, MAX=M ), MAX=M

            ; Draw a horizontal colorbar with all available colors
            ; Default placement is at the bottom of the page.
            ; will be placed at the bottom of the page

        COLORBAR, MIN=0.1, MAX=10, /LOG, UNIT='[ppt]', $
            LABELS=[0.1, 0.5, 1, 5, 10 ], 
            POSITION=[0.3. 0.3, 0.3, 0.3]
 
            ; Draw another colorbar above the first one, 
            ; use logarithmic scale

        COLORBAR, MIN=0.1, MAX=10, /LOG, UNIT='[ppt]', $
            LABELS=[0.1, 0.5, 1, 5, 10 ], 
            POSITION=[0.1, 0.1, 0.1, 0.1], /VERTICAL

            ; Draw vertical colorbar closer to the left edge of 
            ; the plot.  Otherwise options are the same as in the 
            ; previous example.

        COLORBAR, MIN=0, MAX=100, $
            DIVISIONS=5, TOPOUTOFRANGE=!MYCT.WHITE

            ; Draw horizontal colorbar with out-of-range box
            ; (colored white) to the right of the max value.

        COLORBAR, MIN=0, MAX=100, $
            DIVISIONS=5, TOPOUTOFRANGE=!MYCT.WHITE, $
            ANNOTATION=[ '0', '2,500', '5,000', '7,500', '10,000' ]

            ; Same example as above, but this time we use the
            ; ANNOTATION keyword to override the default labels
            ; with string labels.

 MODIFICATION HISTORY:
        mgs, 02 Jun 1998: VERSION 1.00
        mgs, 14 Nov 1998: - changed default format to f14.2 from f6.2
        mgs, 19 Nov 1998: - added cbdefaultformat function to better handle
                            default labeling format.
        mgs, 28 Nov 1998: - default labelling format now exponential for
                            values gt 1.e6
        mgs, 19 May 1999: - unit string placed a little further right
                            in horizontal colorbars.
        mgs, 27 May 1999: - added functionality for discrete colorbars
                            (C_COLORS, C_LEVELS, and SKIP keywords)
        bmy, 02 Jun 1999: - added /SCIENTIFIC keyword
                          - updated comments
        mgs, 03 Jun 1999: - fixed discrete labeling x positions
        bmy, 27 Jul 2000: TOOLS VERSION 1.46
                          - added ORIENTATION keyword so that the user
                            can control the vertical colorbar labels
        bmy, 27 Sep 2002: TOOLS VERSION 1.51
                          - Now use 2 decimal places for exponential
                            default format instead of 3
        bmy, 18 Oct 2002: TOOLS VERSION 1.52
                          - now use _EXTRA=e to pass commands to
                            XYOUTS (i.e. to set label thickness)
        bmy, 26 Nov 2002: - Added ANNOTATION keyword to print
                            string labels instead of numeric labels
        bmy, 26 Nov 2003: TOOLS VERSION 2.01
                          - make sure MINV, MAXV, and DIVISIONS
                            are scalars so as not to generate the
                            color bar labels incorrectly.
        bmy, 21 May 2004: TOOLS VERSION 2.02
                          - If SKIP is passed, make sure that it is
                            never less than 1.
                          - added TICKLEN and FLAGVAL keywords
                          - now add ticks where labels are printed
                          - Cosmetic changes, updated comments
        bmy, 07 Mar 2007: TOOLS VERSION 2.06
                          - Updated documentation and examples
  dbm & bmy, 13 Jun 2007: - Now define default colors for contour plots
                            if C_LEVELS is passed but C_COLORS isn't
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10
  cdh & phs, 19 Nov 2007: GAMAP VERSION 2.11
                          - Added out of range boxes options for
                            vertical bar
                          - Added TRIANGLE and NoGAP keyword
                          - Set default for case of /TRIANGLE, but no
                            OutOfRange boxes.
        phs, 21 Apr 2008: GAMAP VERSION 2.12
                          - Bug fix default MAXV should be NCOLORS+BOTTOM
        cdh, 16 Apr 2013: Fill MinV and MaxV values from C_Levels

(See /n/home09/ryantosca/IDL/gamap2/color/colorbar.pro)


COLORBAR_NDIV

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
        COLORBAR_NDIV

 PURPOSE:
        Returns the maximum number of colorbar divisions possible
        (up to a user-defined limit) such that tickmarks are placed 
        in between colors.

 CATEGORY:
        Color

 CALLING SEQUENCE:
        Result = COLORBAR_NDIV( NCOLORS [, Keywords ] )

 INPUTS:
        NCOLORS -> (OPTIONAL) Specifies the number of colors 
             in the color table.  Default is !MYCT.NCOLORS.

 KEYWORD PARAMETERS:
        MAXDIV -> Specifies the maximum number of divisions 
             for the colorbar.  Default is 6.

 OUTPUTS:
        None

 SUBROUTINES:
        None

 REQUIREMENTS:
        None

 NOTES:
        None

 EXAMPLES:
        DIV = COLORBAR_NDIV( 20, MAXDIV=8 )
        TVMAP, ..., DIVISONS=DIV, ...
             
             ; Computes the number of color bar divisions for
             ; a colortable with 20 colors.  DIV will not exceed
             ; the value of MAXDIV (in this case =8).  The value 
             ; of DIV is then passed to the TVMAP routine (which
             ; in turn passes it to the COLORBAR routine).

 MODIFICATION HISTORY:
        phs, 13 Jul 2007: GAMAP VERSION 2.10

(See /n/home09/ryantosca/IDL/gamap2/color/colorbar_ndiv.pro)


COMPARE_FLIGHT

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
        COMPARE_FLIGHT

 PURPOSE:
        Compare observations from aircraft campaigns to 
        high time-resolution CTM output (bpch files).
        This routine reads aircraft data in binary (bdt) format
        and produces an unlabeld plot and returns all the data
        you might ask for. If an aircraft mission extends beyond
        midnight GMT, the program will ask for a second model file
        which should be from the following day.

 CATEGORY:
        GAMAP Utilities, GAMAP Plotting

 CALLING SEQUENCE:
        COMPARE_FLIGHT, keywords

 INPUTS:
        None

 KEYWORD PARAMETERS:
      DATAFILE -> Name of the aircraft data file or file mask

      MODELFILE -> Name of the (first) model output file or file mask

      TRACER -> tracer number in model output (default=71)

      PSURF -> surface pressure for model grid (default=1013, because most
          aircraft data was sampled over oceans)

      FLIGHTDATA -> returns the observational data array as read
          with gte_readbin. Can also be used to pass flight data if you
          set the USE_DATA flag.

      FLIGHTVARS -> returns the variable names of the observational data.
          Must accompany FLIGHTDATA if you use USE_DATA.

      SPECIES -> the name of the observed species to plot (default CH3I).

      MODELDATA -> returns a time series of model data along the flight 
          track and a couple of min/max values:
             MODELDATA[*,0] = model value in corresponding grid box
                      [*,1] = min of neighbouring grid boxes at same level
                      [*,2] = max ...
                      [*,3] = min of neighbouring grid boxes at level below
                      [*,4] = max ...
                      [*,5] = min of neighbouring grid boxes at level above
                      [*,6] = max ...
          Note that the min/max arrays may contain values from the same
          grid boxes at the edges (i.e. there is no level below the first
          one, hence 3,4 will be identical to 1,2).

      TIME -> returns the time vector of the observations and modeldata

      /USE_DATA -> set this flag if you provide the aircraft data in the
          FLIGHTDATA array and the variable names in FLIGHTVARS. The data
          must contain variables named 'LON', 'LAT', 'ALTP' and SPECIES
          (for SPECIES see above). You must also provide a TIME vector
          which specifies UTC seconds.

 OUTPUTS:
      The extracted data is returned in MODELDATA, several other keywords
      return things read or computed in the process.

 SUBROUTINES:
      EXTRACT__FLIGHT : actual workhorse that does the extraction

 REQUIREMENTS:
      chkstru, ctm_get_data (GAMAP), gte_readbin (GTE)

 NOTES:
      Some hardwiring of default directories.

 EXAMPLE:
      simply  COMPARE_FLIGHT,tracer=1  if all you want is a plot
 
      CONVERT_FLIGHT,tracer=1,modeldata=md,time=time
      plot,time,md[*,0],color=1

 MODIFICATION HISTORY:
      mgs, 21 Apr 1999: VERSION 1.00
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10

(See /n/home09/ryantosca/IDL/gamap2/gamap_util/compare_flight.pro)


COMPRESS_DIV_CT

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
        COMPRESS_DIV_CT

 PURPOSE:
        Compresses a diverging color table with even number of colors 
        into NCOLORS.  If the /MIDCOLORPRESENT keyword is specified,
        COMPRESS_DIV_CT will also place white or yellow spaces in
        the middle of the color table.

 CATEGORY:
	 Color


 CALLING SEQUENCE:
        COMPRESS_DIV_CT, R, G, B [, Keywords ]

 INPUTS:
        R, G, B -> The vectors containing the red, blue, and 
             green color values that define the color table.

 KEYWORD PARAMETERS:
        NCOLORS -> Requested number of colors to be returned.
             If NCOLORS is omitted, then COMPRESS_DIV_CT will
             return without doing anything.

        /MIDCOLORPRESENT -> Set this switch to add 1 or 2 extra
             white or yellow color spaces in the color table.  
            
        /WHITE -> If /MIDCOLORPRESENT is set, this switch will
             cause 1 (if NCOLORS is odd) or 2 (if NCOLORS is even)
             extra white color spaces to be placed
             at the center of the color table.  
            
        /YELLOW -> If /MIDCOLORPRESENT is set, this switch will
             cause 1 (if NCOLORS is odd) or 2 (if NCOLORS is even)
             extra white color spaces to be placed
             at the center of the color table.  ;

 OUTPUTS:
        None

 SUBROUTINES:
        None

 REQUIREMENTS:
        Designed for use with MYCT.  You shouldn't normally 
        have to call COMPRESS_DIV_CT directly.

 NOTES:
        None

 EXAMPLE:
        LOADCT, 63, FILE=FILE_WHICH( 'gamap_colors.tbl' )
        TVLCT, R, G, B, /Get

             ; Load the ColorBrewer "RdBu" table
             ; and return the color vectors

        COMPRESS_DIV_CT, R, G, B, $
                         NCOLORS=20, /MIDCOLORPRESENT, /WHITE

             ; Compress the color table down to 20 colors and 
             ; insert 2 white spaces at the middle of the table.

 MODIFICATION HISTORY:
        phs, 21 Apr 2008: GAMAP VERSION 2.12

(See /n/home09/ryantosca/IDL/gamap2/color/compress_div_ct.pro)


CONVERT_INDEX

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
        CONVERT_INDEX

 PURPOSE:
        Converts a 1-D array index (such as is returned from 
        WHERE, UNIQ, etc) to the appropriate 1-D, 2-D, or 3-D
        array indices

 CATEGORY:
        General

 CALLING SEQUENCE:
        RESULT = CONVERT_INDEX( Index, Dim )

 INPUTS:
        INDEX -> The 1-D array index to be converted to 
             multi-dimensional indices.  INDEX is returned
             to the calling program unchanged.
 
        DIM -> A vector containing the dimensions of the array
             for which multi-dimensional indices are required.

 KEYWORD PARAMETERS:
        FORTRAN -> Interpret array indices as FORTRAN indices, i.e.
             starting from 1 instead of 0. This applies to INPUT 
             and OUTPUT indices!

 OUTPUTS:
        RESULT -> Returns either a vector index or a vector of 
             multi-dimensional array indices as the value of the 
             function. If INDEX is a 1-dimensional parameter, the 
             result will have n_elements(dim) dimensions. If INDEX 
             is a multidimensional parameter, the result will be 
             a scalar.

 SUBROUTINES:
        None

 REQUIREMENTS:
        None

 NOTES:
        Right now only works for 3-D arrays and smaller.  Will
        eventually do the general case...

 EXAMPLES:
        (1) 
        PRINT, CONVERT_INDEX( [1,1], [2,2] )
           3

        (2)
        PRINT, CONVERT_INDEX( [2,2], [2,2] )
           % CONVERT_INDEX: Index[0] greater than Dim[0]
           % CONVERT_INDEX: Index[1] greater than Dim[1]
           6

        (3)
        PRINT, CONVERT_INDEX( [2,2], [2,2], /FORTRAN )
           4       ; <<<-- shifted by 1 !

        (4)
        PRINT, CONVERT_INDEX( 72, [72,46,20] )
           0  1  0
 
        (5)
        PRINT, CONVERT_INDEX( 72, [72,46,20], /FORTRAN )
           72           1           1
 
 MODIFICATION HISTORY:
        bmy, 07 Oct 1998: VERSION 1.00
        mgs, 07 Oct 1998: VERSION 1.20
               - made result etc LONG arrays
               - allow sany dimensions now
               - added reverse operation if index is multidimensional
               - added FORTRAN keyword 
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10

(See /n/home09/ryantosca/IDL/gamap2/general/convert_index.pro)


CONVERT_KG_MOLCM2

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
        CONVERT_KG_MOLCM2 

 PURPOSE:
        Converts the units of a 2-D array from kg to molecules/cm2 
        (or kg/s to molecules/cm2/s).  

 CATEGORY:
        Math & Units

 CALLING SEQUENCE:
        CONVERT_KG_MOLCM2, DATA, AREACM2, KGPERMOLE

 INPUTS:
        DATA -> 2-D array of data values in units of
             kg or kg s^-1.

        AREACM2 -> 2-D array containing the surface area of each
             gridbox in cm^2

        KGPERMOLE -> The molecular weight of the tracer or
             molecule, in units of kg mole^-1.

 OUTPUTS:
        DATA -> The converted array in molecules cm^-2 s^-1
             is returned in DATA. 

 KEYWORD PARAMETERS:
        None

 SUBROUTINES:
        None

 REQUIREMENTS:
        CTM_SURFACE_AREA must be called to compute the AREACM2 array.
        TRACER_KG_PER_MOLE (or a similar subroutine) must be called
        to compute the KGPERMOLE array.
             
 NOTES:
        None

 EXAMPLE:
        AreaCm2      = CTM_SURFACE_AREA( GridInfo, /cm2, /GEOS )
        KgPerMole    = TRACER_KG_PER_MOLE( /FULLCHEM )
        TracerNumber = 1  ; for NOx  
        CONVERT_KG_MOLCM2, Data, AreaCm2, KgPerMole(TracerNumber)

            ; Will convert the Data array for the GEOS-1 model (using
            ; the molecular weight for NOx) from kg/s to molecules/cm2/s.
             
 MODIFICATION HISTORY:
        bmy, 07 Apr 1998: VERSION 1.00
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10

(See /n/home09/ryantosca/IDL/gamap2/math_units/convert_kg_molcm2.pro)


CONVERT_LON

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
        CONVERT_LON

 PURPOSE:
        Convert longitudes from -180..180 to 0..360 
        or vice versa.

 CATEGORY:
        General

 CALLING SEQUENCE:
        CONVERT_LON, DATA, NAMES, [, KEywords ] 

 INPUTS:
        DATA -> A data array (lines,vars) or vector containing 
            longitude data. If DATA is a 2D array, the NAMES
            parameter must be given to identify the LONgitude variable.

        NAMES -> A string list of variable names. The longitude data
            must be labeled 'LON', unless specified with the LONNAME
            keyword. The NAMES parameter is not needed, if a data
            vector is passed.

 KEYWORD PARAMETERS:
        PACIFIC -> Convert longitudes from -180..180 to 0..360

        ATLANTIC -> Convert from 0..360 to -180..180

        LONNAME -> Name of the longitude variable if a name other
            than 'LON' is used.

 OUTPUTS:
        The longitude column in the data array will be changed.

 SUBROUTINES:
        None

 REQUIREMENTS:
        None

 NOTES:
        None

 EXAMPLES:
        (1)
        LONDAT = [ -180.,-179.,-0.1,0.1,179.,180.,270.,359.]
        CONVERT_LON, LONDAT, /PACIFIC
        PRINT, LONDAT
           180.000  181.000  359.900  0.100000  
           179.000  180.000  270.000  359.000

             ; Convert longitudes to 0..360

        (2)
        CONVERT_LON,londat,/Atlantic
        PRINT, LONDAT
           180.000  -179.000  -0.100006  0.100000      
           179.000   180.000  -90.0000  -1.00000

             ; Convert back to -180..180

 MODIFICATION HISTORY:
        mgs, 25 Aug 1998: VERSION 1.00
        mgs, 19 May 1999: - now makes sure that longitude range does
                            not exceed -180..180 or 0..360
        mgs, 24 Jun 1999: - bug fix: choked at missing values 
        bmy, 24 May 2007: TOOLS VERSION 2.06
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10
                          - Updated comments
        phs, 19 Nov 2007: GAMAP VERSION 2.11
                          - now accept scalar

(See /n/home09/ryantosca/IDL/gamap2/general/convert_lon.pro)


CONVERT_MOLCM2_KG

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
        CONVERT_MOLCM2_KG 

 PURPOSE:
        Converts the units of a 2-D or 3-D array from molecules/cm2 
        to kg (or, equivalently, from molecules/cm2/s to kg/s).  

 CATEGORY:
        Math & Units

 CALLING SEQUENCE:
        CONVERT_MOLCM2_KG, DATA, AREACM2, KGPERMOLE

 INPUTS:
        DATA -> 2-D or 3-D array of data values in units of
             molecules cm^-2 or molecules cm^-2 s^-1.

        AREACM2 -> 2-D array containing the surface area of each
             gridbox in cm^2

        KGPERMOLE -> The molecular weight of the tracer or
             molecule, in units of kg/mole.
 
 OUTPUTS:
        DATA -> The converted array in kg/s is returned in DATA. 
             DATA is returned with the same dimensions as
             it had when it was passed to CONVERT_MOLCM2_KG.

 KEYWORD PARAMETERS:
        None

 SUBROUTINES:
        None

 REQUIREMENTS:
        CTM_SURFACE_AREA must be called to compute the AREACM2 array.
        TRACER_KG_PER_MOLE (or a similar subroutine) must be called
        to compute the KGPERMOLE array.
             
 NOTES:

 EXAMPLE:
        AreaCm2      = CTM_SURFACE_AREA( GridInfo, /cm2, /GEOS )
        KgPerMole    = TRACER_KG_PER_MOLE( /FULLCHEM )
        TracerNumber = 1   ; for NOx
        CONVERT_MOLCM2_KG, Data, AreaCm2, KgPerMole

            Will convert the Data array for the GEOS-1 model (using
            the molecular weight for NOx) from molecules/cm2/s to kg/s.
             

 MODIFICATION HISTORY:
        bmy, 07 Apr 1998: VERSION 1.00
        bmy, 09 Apr 1998: VERSION 1.01 
                          - DATA can now be a 2-D or 3-D array.
                          - KgPerMole can now be an array of the same
                            dimension as the 3rd dimension of Data.
        bmy, 07 Oct 1998: VERSION 1.02
                          - now uses MESSAGE statement
                          - also uses [] instead of () for array
                            indices
        bmy  23 Nov 1998: VERSION 2.00
                          - now uses double precision array NEWDATA
                            to avoid overflow/underflow errors
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10

(See /n/home09/ryantosca/IDL/gamap2/math_units/convert_molcm2_kg.pro)


CONVERT_O3PL

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
        CONVERT_O3PL

 PURPOSE:
        Converts single-tracer Ox rate files from their native
        binary format to binary punch format 

 CATEGORY:
        File & I/O, BPCH Format

 CALLING SEQUENCE:
        CONVERT_O3PL [, Keywords ]

 INPUTS:
        None

 KEYWORD PARAMETERS:
        INMODELNAME -> A string containing the name of the model
             grid on which the input data resides.  Default is GEOS_STRAT.

        INRESOLUTION -> Specifies the resolution of the model grid
             on which the input data resides.  RESOLUTION can be 
             either a 2 element vector with [ DI, DJ ] or
             a scalar (DJxDI: 8=8x10, 4=4x5, 2=2x2.5, 1=1x1, 
             0.5=0.5x0.5).  Default is 2.

 OUTPUTS:
        None

 SUBROUTINES:
        External Subroutines Required:
        ==============================
        CTM_TYPE          (function)  
        CTM_GRID          (function)
        CTM_MAKE_DATAINFO (function)

 REQUIREMENTS:
        None

 NOTES:
        Input file names are hardwired for now.

 EXAMPLE:
        CONVERT_O3PL, INMODELNAME   ='GEOS1',                $
                      INRESOLUTION  = 4,                     $

             ; Regrids P(O3) and L(O3) data from 
             ; GEOS-1 4 x 5 grid to GISS-II-PRIME 4 x 5 grid.

 MODIFICATION HISTORY:
        bmy, 16 Jul 2002: VERSION 1.00
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10
        bmy, 02 Apr 2008: GAMAP VERSION 2.12
                          - Now read input file as big-endian

(See /n/home09/ryantosca/IDL/gamap2/file_io/convert_o3pl.pro)


CONVERT_UNIT

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
        CONVERT_UNIT

 PURPOSE:
        Convert data to a different unit. You can either 
        replace a unit by the corresponding standard SI unit or 
        replace a specific unit with another one.

 CATEGORY:
        Math & Units

 CALLING SEQUENCE:
        CONVERT_UNIT,DATA,UNIT,TOPARAM [,keywords]

 INPUTS:
        DATA -> A data vector, array, or a single value that shall
            be converted to a new unit. 

        UNIT -> A string variable containing the (current) unit of 
            DATA. This will be replaced by the new unit afterwards.
            If omitted, you must give the FROM_UNIT keyword to indicate
            the current unit of DATA.

        TOPARAM -> The unit to convert DATA to. This is equivalent to 
            the keyword TO_UNIT and overwrites it.

 KEYWORD PARAMETERS:
        FROM_UNIT -> An individual unit to search and replace. If not
            given, any unit will be converted to TO_UNIT, as long as
            the current unit belongs to the same category. 

        TO_UNIT -> An individual unit to convert to. If not given, all
            unit that are converted (see FROM_UNIT) will be replaced
            by the standard SI unit of their category.

        For the individual unit and categories see FIND_UNIT 

        RESULT -> returns 1 if conversion was successful, 0 otherwise
            This keyword is mostly for consistency witholder routines.
            It is more convenient to test !ERROR_STATE.CODE for being
            0.

        MINVAL -> minimum valid data value. Only data above this 
            value will be converted (default: -1.E30)

        QUIET -> In case of an error, an error message is displayed,
            and the !ERROR_STATUS system variable is set to reflect the
            error condition (program execution continues). Set the
            QUIET keyword to suppress the error message.

 OUTPUTS:
        DATA will be converted and unit will contain new names.

 SUBROUTINES:
        Uses FIND_UNIT

 REQUIREMENTS:
        None

 NOTES:
        CONVERT_UNIT wil return the value and unit unchanged if
        the unit was not found in the standard list (see FIND_UNIT)
        or the category of the target unit does not match the
        category of the source unit. In these cases, !ERROR_STATE.CODE
        will be set to signal an error condition.

 EXAMPLE:
        ; create some data
        data = findgen(100)
        unit = 'cm'

        ; convert all data to SI unit of same category (m)
        convert_unit,data,unit

        ; test success
        if (!ERROR_STATE.CODE ne 0) then stop

        ; convert temperature in Fahrenheit to 'deg C'
        ; (multiple calls to capture all different spellings)
        ; Data will only be changed if unit is indeed Fahrenheit
        convert_unit,data,unit,from='F',to='deg C'
        convert_unit,data,unit,from='degF',to='deg C'
        convert_unit,data,unit,from='deg F',to='deg C'

        ; (easier way) convert any temperature to 'C'
        ; This will also convert 'K' !
        ; Don't display error message
        convert_unit,data,unit,to='C',/QUIET

        ; convert 'mph' data to SI ('m/s')
        convert_unit,data,unit,from='mph'

        ; explicitely convert 'cm' to 'm'
        convert_unit,data,'cm','m'
        ; equivalent to
        convert_unit,data,from='cm',to='m'

 MODIFICATION HISTORY:
        mgs, 26 Aug 1998: VERSION 1.00
        mgs, 27 Aug 1998: 
            - added RESULT and QUIET keywords
            - improved error handling
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10

(See /n/home09/ryantosca/IDL/gamap2/math_units/convert_unit.pro)


CREATE3DFSTRU

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
        CREATE3DFSTRU

 PURPOSE:
        Creates an empty GAMAP fileinfo structure or an array
        of such structures. These are used to hold information
        about CTM data files.

 CATEGORY:
        GAMAP Internals, Structures

 CALLING SEQUENCE:
        FILEINFO = CREATE3DHSTRU( [Elements] )

 INPUTS:
        ELEMENTS -> Number of individual structures to
             be contained in the array of structures. Default
             is 1, i.e. return a single structure.

 KEYWORD PARAMETERS:
        None

 OUTPUTS:
        A fileinfo structure or an array of fileinfo structures.

 SUBROUTINES:
        None

 REQUIREMENTS:
        None

 NOTES:
        See comments in code below for structure field descriptions.

 EXAMPLES:
        FILEINFO = CREATE3DFSTRU()
            ; returns a single structure which will hold
            ; info about CTM punch file data.

        FILEINFO = CREATE3DFSTRU( 20 )
            ; returns an 20 element array of structures 
            ; which will hold info about 20 records from a 
            ; CTM data file

 MODIFICATION HISTORY:
        mgs, 14 Aug 1998: VERSION 1.00
        bmy, 18 May 2007: GAMAP VERSION 2.06
                          - added standard doc header
                          - updated comments, cosmetic changes
 MODIFICATION HISTORY:
        bmy, 19 Feb 1999: VERSION 1.00
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10

(See /n/home09/ryantosca/IDL/gamap2/internals/create3dfstru.pro)


CREATE3DHSTRU

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
        CREATE3DHSTRU

 PURPOSE:
        Creates an empty GAMAP datainfo structure or an array
        of such structures. These are used to hold information
        about individual data blocks from CTM data files.

 CATEGORY:
        GAMAP Internals, Structures

 CALLING SEQUENCE:
        DATAINFO = CREATE3DHSTRU( [Elements] )

 INPUTS:
        ELEMENTS -> Number of individual structures to be contained 
             in the array of structures. Default is 1, (i.e. return
             a single structure).

 KEYWORD PARAMETERS:
        None

 OUTPUTS:
        A datainfo structure or an array of datainfo structures.

 SUBROUTINES:
        None

 REQUIREMENTS:
        None

 NOTES:
        See comments in code below for structure field descriptions.

 EXAMPLES:
        DATAINFO = CREATE3DHSTRU()
            ; returns a single structure which will hold
            ; info about CTM punch file data.

        DATAINFO = CREATE3DHSTRU( 20 )
            ; returns an 20 element array of structures 
            ; which will hold info about 20 records from a 
            ; CTM data file

 MODIFICATION HISTORY:
        mgs, 14 Aug 1998: VERSION 1.00
        mgs, 10 Nov 1998: - changed default filepos to -1L and scale to 1
        bmy, 08 Feb 1999: VERSION 1.10
                          - changed TAU0, TAU1 from longword to double
                          - added OFFSET field for I0, J0, L0
        bmy, 17 Feb 1999: VERSION 1.20
                          - changed OFFSET field to FIRST since we
                            are storing the I, J, L indices of the 
                            first 
        mgs, 16 Mar 1999: - cosmetic changes
        bmy, 03 Jan 2000: VERSION 1.44
                          - updated comments
        bmy, 26 Apr 2000: VERSION 1.45
                          - TRACER now carries a longword variable
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10
        phs, 02 Dec 2008: GAMAP VERSION 2.13
                          - DIM tag is 32-bit integer (LONG) now
        bmy, 23 Feb 2012: GAMAP VERSION 2.16
                          - Now make FILEPOS a LONG64 variable, in
                            order to read files larger than 2.4 GB
                          - Now make FIRST an array of LONG variables

(See /n/home09/ryantosca/IDL/gamap2/internals/create3dhstru.pro)


CREATE_NESTED

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 NAME:
        CREATE_NESTED

 PURPOSE:
        Reads data from a file and trims it down horizontally to a 
        "nested" CTM grid size.  Vertical resolution is not affected.

 CATEGORY:
        Regridding

 CALLING SEQUENCE:
        CREATE_NESTED [, Keywords ]

 INPUTS:
        None

 KEYWORD PARAMETERS:
        INFILENAME -> Name of the input file containing data to be 
             trimmed down to "nested" model grid resolution.  If 
             omitted, a dialog box will prompt the user to supply
             a filename.

        OUTFILENAME -> Name of the file that will contain trimmed
             data on the "nested" model grid.  OUTFILENAME will be
             in binary punch resolution.  If omitted, a dialog box 
             will prompt the user to supply a filename.

        XRANGE -> A 2-element vector containing the minimum and
             maximum box center longitudes which define the nested
             model grid. Default is [-180,180].

        YRANGE -> A 2-element vector containing the minimum and
             maximum box center latitudes which define the nested
             model grid. Default is [-180,180].

        /CHINA -> Set this switch to create nested-grid met data
             fil}es for the CHINA region.  Setting this switch will
             override the XRANGE and YRANGE keywords.

        /NAMER -> Set this switch to create nested-grid met data
             files for the NORTH AMERICA region.  Setting this switch 
             will override the XRANGE and YRANGE keywords.

        /EUROPE -> Set this switch to create nested-grid met data
             files for the EUROPE region.  Setting this switch will
             override the XRANGE and YRANGE keywords.
             ### NOTE: Need to define the region as of 10/4/07 ###

 OUTPUTS:
        None

 SUBROUTINES:
        Internal Subroutines:
        ================================================
        CN_GETRANGES
 
        External Subroutines Required:
        ================================================
        CTM_CLEANUP         CTM_GET_DATA
        CTM_WRITEBPCH       CTM_MAKE_DATAINFO (function)
        GETMODELANDGRIDINFO   

 REQUIREMENTS:
        None

 NOTES:
        (1) Works for the following types of data blocks:
            (a) 2-D "zonal-mean" (latitude-altitude)
            (b) 2-D "horizontal" (longitude-latitude)
            (c) 3-D "global"     (longitude-latitude-altitude)

 EXAMPLE:
        (1)
        CREATE_NESTED, INFILENAME='global_grid.bpch', $
                       OUTFILENAME='nested_grid.bpch, $
                       XRANGE=[ -150, -30 ],          $
                       YRANGE=[   10,  70 ]

             ; Trims data from "global_grid.bpch" to a nested grid 
             ; from 150W to 30W and 10N to 70N (in this example,
             ; this covers the US and parts of Canada and Mexico).

        (2)
        CREATE_NESTED, INFILENAME='global_grid.bpch', $
                       OUTFILENAME='nested_grid.bpch, /CHINA

             ; Trims data from "global_grid.bpch" to a nested grid 
             ; for the default China nested grid (70-150E and 11S 
             ; to 55 N).  The /CHINA keyword is a convenience to the
             ; user.  It will set XRANGE and YRANGE automatically for
             ; the China nested grid.


 MODIFICATION HISTORY:
        bmy, 10 Jan 2003: VERSION 1.00
        bmy, 25 Sep 2003: VERSION 1.01
                          - now call PTR_FREE to free pointer heap memory
        bmy, 16 Dec 2003: - now add THISFILEINFO in call to CTM_WRITEBPCH
  bmy & phs, 04 Oct 2007: GAMAP VERSION 2.10
                          - Added /CHINA, /NAMER, /EUROPE keywords
                            which may be specified instead of XRANGE
                            and YRANGE.  This is a user convenience.
        phs, 28 Jan 2008: - Bug fix if model name is 'GEOS3_30L'
                          - Free pointers not referenced at exist.
        lhu, 12 Jan 2012: GAMAP VERSION 2.16
                          - Better test for small number equality
                          - Add SEA4CRS nested grid range
        mps, 06 Nov 2013: - Remove SEAC4RS nested grid
                          - Add NAMER grid for GEOS-FP
        mps, 28 Oct 2015: - Add NAMER and CHINA grids for MERRA2

(See /n/home09/ryantosca/IDL/gamap2/regridding/create_nested.pro)


CREATE_NESTED_ASCII

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
        CREATE_NESTED_ASCII

 PURPOSE:
        Reads data from an ASCII file and trims it to nested-grid
        resolution.  Also renumbers I and J from "global" to "window" 
        coordinates.  Vertical and temporal resolution are not affected.

 CATEGORY:
        Regridding

 CALLING SEQUENCE:
        CREATE_NESTED_ASCII [, Keywords ]

 INPUTS:
        None

 KEYWORD PARAMETERS:
        INMODELNAME -> A string containing the name of the model 
             grid on which the input data resides.  Default is 'GEOS3'.

        INRESOLUTION -> Specifies the resolution of the model grid
             on which the input data resides.  INRESOLUTION
             can be either a 2 element vector with [ DI, DJ ] or
             a scalar (DJxDI: 8=8x10, 4=4x5, 2=2x2.5, 1=1x1, 
             0.5=0.5x0.5).  Default is 1.

        INFILENAME -> Name of the input file containing data to be 
             trimmed down to "nested" model grid resolution.  If 
             omitted, a dialog box will prompt the user to supply
             a filename.

        OUTFILENAME -> Name of the file that will contain trimmed
             data on the "nested" model grid.  OUTFILENAME will be
             in binary punch resolution.  If omitted, a dialog box 
             will prompt the user to supply a filename.

        XRANGE -> A 2-element vector containing the minimum and
             maximum box center longitudes which define the nested
             model grid. Default is [-180,180].

        YRANGE -> A 2-element vector containing the minimum and
             maximum box center latitudes which define the nested
             model grid. Default is [-180,180].

        HEADER -> Number of header lines to skip over.

        FORMAT -> String describing the input file format.  
             Default is '(2i3,a)', i.e., two 3-digit integers
             and then an unspecified length character line.

 OUTPUTS:
        None

 SUBROUTINES:
        External Subroutines Required:
        ================================================
        CTM_TYPE (function)   CTM_GRID (function)
        OPEN_FILE

 REQUIREMENTS:
        None

 NOTES:
        (1) Assumes I and J (the lon & lat grid box indices) 
            are the first two items on each line.

        (2) Assumes that the nested-grid does not wrap around
            the date line.  

 EXAMPLE:
        CREATE_NESTED_ASCII, INFILENAME='fert_scale.dat.1x1', $
                             OUTFILENAME='fert_scale.dat,     $
                             XRANGE=[ -140, -40 ],            $
                             YRANGE=[   10,  60 ],            $
                             FORMAT='(2i6,a)

             ; Trims data from "fert_scale.dat.1x1" to a GEOS-3
             ; 1x1 (default values) nested grid from 14OW to 4OW 
             ; and 10N to 60N (in this example, this covers the US 
             ; and parts of Canada and Mexico).

 MODIFICATION HISTORY:
        bmy, 10 Apr 2003: VERSION 1.00
  bmy & phs, 20 Jun 2007: GAMAP VERSION 2.10

(See /n/home09/ryantosca/IDL/gamap2/regridding/create_nested_ascii.pro)


CREATE_NESTED_MET

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
        CREATE_NESTED_MET

 PURPOSE:
        Reads GEOS-Chem binary met data files at global resolution
        and creates new files that have been "cut down" to a 
        particular nested-grid region (e.g. China, North America,
        Europe).  Vertical resolution is not affected.

 CATEGORY:
        Regridding

 CALLING SEQUENCE:
        CREATE_NESTED_MET [, Keywords ]

 INPUTS:
        None

 KEYWORD PARAMETERS:
        INFILENAME -> Name of the input file containing data to be 
             trimmed down to "nested" model grid resolution.  If 
             omitted, a dialog box will prompt the user to supply
             a filename.

        OUTFILENAME -> Name of the file that will contain trimmed
             data on the "nested" model grid.  OUTFILENAME will be
             in binary punch resolution.  If omitted, a dialog box 
             will prompt the user to supply a filename.

        /CHINA -> Set this switch to create nested-grid met data
             files for the CHINA region.

        /NAMER -> Set this switch to create nested-grid met data
             files for the NORTH AMERICA region.

        /EUROPE -> Set this switch to create nested-grid met data
             files for the EUROPE region.
             ### NOTE: Need to define the region as of 10/4/07 ###

        /VERBOSE -> Set this switch to print extra informational
             messages to the screen.

 OUTPUTS:
        None

 SUBROUTINES:
        Internal Subroutines:
        ================================================
        CNM_GETGRID            CNM_GETCORNERS

        External Subroutines Required:
        ================================================
        CTM_INDEX
        CTM_TYPE  (function)   CTM_GRID (function)

 REQUIREMENTS:
        None

 NOTES:
        (1) Works for the following types of data blocks:
            (a) 2-D "horizontal" (longitude-latitude)
            (b) 3-D "global"     (longitude-latitude-altitude)

 EXAMPLE:
        CREATE_NESTED_MET, INFILENAME='20021031.i6.1x1',      $
                           OUTFILENAME='20021031.i6.1x1.USA', $
                           /NAMER

             ; Trims DAO met data from "20021031.i6.1x1" to a nested 
             ; grid from 150W to 30W and 10N to 70N (in this example,
             ; this covers the US and parts of Canada and Mexico).

 MODIFICATION HISTORY:
        bmy, 18 Jan 2003: VERSION 1.00
                          - adapted from "create_nested.pro"  
        bmy, 25 Sep 2003: VERSION 1.01
                          - also added GEOS-4 met fields
  bmy & phs, 24 Sep 2007: GAMAP VERSION 2.10
                          - Rewritten for compatibility with
                            GAMAP internal routine CTM_READ_GMAO
        bmy, 02 Apr 2008: GAMAP VERSION 2.12
                          - Make sure we create big-endian binary files

(See /n/home09/ryantosca/IDL/gamap2/regridding/create_nested_met.pro)


CREATE_TAGOX_RESTART

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 NAME:
        CREATE_TAGOX_RESTART

 PURPOSE:
        Creates an initial tagged-Ox restart file w/ 13 tracers
        (i.e. corresponding to Arlene Fiore's original runs)

 CATEGORY:
        File & I/O

 CALLING SEQUENCE:
        CREATE_TAGOX_RESTART

 INPUTS:
        None
        
 KEYWORD PARAMETERS:
        FILENAME -> Name of full-chemistry restart file containing Ox 
             data (stored under tracer #2) to be used in creating a 
             Tagged Ox restart file.

        OUTFILENAME -> Name of the Tagged Ox restart file that will
             be created.  Default is "restart.Ox".

        /ZERO_STRAT -> Set this
         
 OUTPUTS:
        None

 SUBROUTINES:
        External subroutines required:
        ==============================
        CTM_GRID          (function)  
        CTM_MAKE_DATAINFO (function)
        CTM_WRITEBPCH

 REQUIREMENTS:
        None

 NOTES:
        Assumes Ox tracers have an offset of 40.

 EXAMPLE:
        CREATE_TAGOX_RESTART, FILENAME='gctm.trc.20010701', $
                              OUTFILENAME="gctm.trc.20010701.Ox'
             
             ; Reads Ox from a full chemistry restart file and
             ; creates a tagged-Ox restart file for initial spinup.

 MODIFICATION HISTORY:
        bmy, 18 Aug 2003: VERSION 1.01
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10

(See /n/home09/ryantosca/IDL/gamap2/file_io/create_tagox_restart.pro)


CREATE_USA_MASK

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
        CREATE_USA_MASK

 PURPOSE:
        This program defines a mask over the USA.  All grid boxes
        that are totally contained w/ in the continental US are
        set equal to 1, with zeroes everywhere else.  Boxes that
        the USA shares w/ another country are set to zero.
         
 CATEGORY:
        Regridding

 CALLING SEQUENCE:
        CREATE_USA_MASK [, Keywords ]

 INPUTS:

 KEYWORD PARAMETERS:
        OUTMODELNAME -> Name of the CTM model grid on which the
             mask is to be created.  Default is "GEOS_4".  NOTE:
             since the mask is only a 2-D quantity, all vertical
             layer information will be ignored.

        OUTRESOLUTION -> Resolution of the CTM model grid on 
             which the mask is to be created.  Default is 2.

        OUTFILENAME -> Name of the output file (BPCH format) which
             will contain the USA mask data.  Default is 
             "usa_mask.geos.{RESOLUTION}"

 OUTPUTS:
        None

 SUBROUTINES:
       External Subroutines Required:
       =====================================================
       CTM_TYPE          (function)   CTM_GRID   (function)
       CTM_MAKE_DATAINFO (function)   CTM_RESEXT (function)
       CTM_WRITEBPCH

 REQUIREMENTS:
        None

 NOTES:
        May not yet work for 4x5.

 EXAMPLE:
        CREATE_USA_MASK, OUTMODELNAME="GEOS4",           $
                       OUTRESOLUTION=4,                $
                       OUTFILENAME='usa_mask.geos.4x5'

             ; Creates a USA mask for the GEOS-4 4x5 grid and
             ; saves it to a bpch file named "us_mask.geos.4x5"

 MODIFICATION HISTORY:
  rch & bmy, 22 Jun 2004: VERSION 1.00
  bmy & phs, 20 Jun 2007: GAMAP VERSION 2.10

(See /n/home09/ryantosca/IDL/gamap2/regridding/create_usa_mask.pro)


CTM_BOXSIZE (FUNCTION)

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
        CTM_BOXSIZE  (function)

 PURPOSE:
        Computes the size of CTM grid boxes.

 CATEGORY
        GAMAP Utilities, GAMAP Models & Grids

 CALLING SEQUENCE:
        result = CTM_BOXSIZE( GRIDINFO [,RADIUS [,KEYWORDS] ] ) 

 INPUTS:
        GRIDINFO -> the structure returned by function CTM_GRID,
             which contains the following necessary fields:
	      IMX   (int   ) -> Maximum I (longitude) dimension 
             JMX   (int   ) -> Maximum J (latitude ) dimension
             YMID  (fltarr) -> Array of latitude  centers

        RADIUS -> The radius of the earth in km.  This may be 
             passed as an input parameter, or can be specified via 
             the GEOS_RADIUS, GISS_RADIUS, or FSU_RADIUS keywords.
             As default, the GEOS value of 6375.0 km is used.

 OUTPUT:
        CTM_BOXSIZE returns a 2-D (or 1D) array of CTM surface areas,
        or a 3-D array for CTM grid box volumes.  The default unit 
        is square kilometers or cubic kilometers.

 KEYWORD PARAMETERS:
        /CM2 -> Return ctm surface areas in square centimeters.
             [default: km^2].  

        /M2 -> Return ctm_surface areas in square meters.
             [default: km^2].  

        /CM3 -> Return grid box volumes in cubic centimeters.  
             [default: km^3].
 
        /M3 -> Return grid box volumes in cubic meters.  
             [default: km^3].

        /VOLUME -> Will cause CTM_BOXSIZE to return grid box volumes 
             instead of grid box surface areas.
       
        GEOS_RADIUS -> selects GEOS value for earth radius (6375.0 km) 
             [default]

        GISS_RADIUS -> selects GISS value for earth radius (6371.4 km)

        FSU_RADIUS -> selects FSU value for earth radius (6371.4 km)
      
        IJ, IL, JL -> determine which area shall be computed [default: IJ]
             NOTE: IL computes area of southern boundary

        XLEN, YLEN, ZLEN -> Returns length of linear segments 
             (lat, lon, alt) to calling program.  If /CM2 or /CM3 is 
             specified, then XLEN, YLEN, ZLEN will be in centimeters.
             If /M2 or /M3 are specified, then XLEN, YLEN, ZLEN will
             be in meters. (Default unit is km).

        NO_2D -> return 1D vector instead of 2D array

        LATIND -> for IL and JL: return result for given latitude index
             [default is equator]. This implies NO_2D. The index must
             be provided as FORTRAN index (e.g. 1..72).
 
 SUBROUTINES:
        External Subroutines Required:
        ===============================
        CHKSTRU (function)   USAGE

 REQUIREMENTS:
        None

 NOTES:
        None

 EXAMPLES:
        ; (1) Compute surface grid box areas for GISS II model in
        ;     standard resolution (4x5):

        Areakm2 = CTM_BOXSIZE( CTM_GRID( CTM_TYPE( 'GISS_II' ), /GISS )

        ; (2) Compute ctm surface areas in cm2 for GEOS 4x5 grid, return
        ;     a vector with 1 value per latitude :

        ModelInfo = CTM_TYPE( 'GEOS1', res=4 )
        GridInfo  = CTM_GRID( ModelInfo )
        AreaCm2   = CTM_BOXSIZE( GridInfo, /GEOS, /cm, /NO_2D )

        ; (3) Compute ctm grid box volumes in cm3 for GEOS 4x5 grid,
        ;     and return a 3-D array

        ModelInfo = CTM_TYPE( 'GEOS1', res=4 )
        GridInfo  = CTM_GRID( ModelInfo )
        VolumeCm3 = CTM_BOXSIZE( GridInfo, /GEOS, /Volume, /cm3 )
        

 MODIFICATION HISTORY:
        bmy, 27 Mar 1998: VERSION 1.00 (algorithm from mgs)
        mgs, 27 Mar 1998: - added NO_2D keyword
        mgs, 07 May 1998: VERSION 1.10
                          - added IJ, IL, JL, LATIND, XLEN, 
                            YLEN, and ZLEN keywords
                          - corrected polar box sizes 
                            (now uses gridinfo information)
        mgs, 08 May 1998: - corrected latindex, now uses FORTRAN convention
        mgs, 24 May 1998: - changed IL so it computes area of 
                            southern boundary
        mgs, 17 Nov 1998: - changed keywords GISS and GEOS to .._RADIUS
        bmy, 27 Jul 1999: VERSION 1.42
                          - updated comments
        bmy, 27 Jan 2000: VERSION 1.45
                          - added /CM and /M keywords,
                            deprecated /CM2 and /M2 keywords.
                          - now return a 3-D array for grid box volumes
                          - updated comments
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10
                          - now call USAGE to display doc header
                            if wrong # of arguments are passed.
                          - Deleted internal routine USE_CTM_BOXSIZE

(See /n/home09/ryantosca/IDL/gamap2/gamap_util/ctm_boxsize.pro)


CTM_CLEANUP

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 NAME:
        CTM_CLEANUP

 PURPOSE: 
        Free memory blocked by excessive use of the GAMAP package.
        With the /DATA_ONLY option, only the data blocks themselves
        are freed, all header information remains accessible. 
        This speeds up any further analysis.  Also calls HEAP_GC
        to do garbage collection on unused heap variables.

 CATEGORY:
        GAMAP Utilities

 CALLING SEQUENCE:
        CTM_CLEANUP [, /DATA_ONLY, /NO_GC, /NO_FILE_CLOSE ]

 INPUTS:
        none

 KEYWORD PARAMETERS:
        /DATA_ONLY -> Only free heap variables that point to the
             actual data records. Leave all 'info' intact. Default 
             is to remove everything includign the global DATAINFO 
             and FILEINFO structure arrays.  NOTE: Setting this switch
             will not perform garbage collection via routine HEAP_GC.
           
        /NO_GC -> Set this switch to suppress garbage collection of
             heap variables with HEAP_GC.

        /NO_FILE_CLOSE -> Set this switch to suppress closing of
             all open files.

 OUTPUTS:
        None

 SUBROUTINES:
        None

 REQUIREMENTS:
        None

 NOTES:
        None

 EXAMPLE:
        CTM_CLEANUP

 MODIFICATION HISTORY:
        mgs, 05 Oct 1998: VERSION 1.00
        mgs, 08 Oct 1998: - fixed DATA_ONLY part so that status is
                            reset to zero and derived data records 
                            are removed
        bmy, 21 Nov 2000: - Updated comments 
        bmy, 04 Oct 2004: GAMAP VERSION 2.03
                          - added /NO_GC keyword
                          - now call HEAP_GC to do garbage collection
                            of heap variables & pointers
        bmy, 23 Mar 2007: GAMAP VERSION 2.06
                          - Now add /NO_FILE_CLOSE keyword so as not
                            to close open files
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10
                          - close only files opened with GAMAP
        bmy, 16 May 2011: GAMAP VERSION 2.16
                          - Now make all loop indices long integers

(See /n/home09/ryantosca/IDL/gamap2/gamap_util/ctm_cleanup.pro)


CTM_COLUMN_DU

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
        CTM_COLUMN_DU

 PURPOSE:
        Calculates columns in Dobson Units for a given tracer.

 CATEGORY:
        GAMAP Utilities

 CALLING SEQUENCE:
        RESULT = CTM_COLUMN_DU( DiagN, [ Keywords ] )

 INPUTS:
        DIAGN -> Diagnostic category name (or number) containing the
             tracer data for which columns will be computed.  The
             default is 'IJ-AVG-$' (i.e. v/v mixing ratios).
             
 KEYWORD PARAMETERS:
        FILENAME -> (OPTIONAL) File containing CTM data for which 
             to compute columns.  If omitted, then the user will
             be prompted to select a file via a dialog box.

        TAU0 -> Starting TAU value of the desired data block (will
             be passed to CTM_GET_DATABLOCK).  If omitted, then 
             CTM_COLUMN_DU will read data for the first time in
             the data file.

        TRACER -> Number of tracer for which to compute columns.

        PFILENAME -> Name of the file containing surface pressure
             data (this is necessary in order to compute column
             sums).  If PFILENAME is omitted, then CTM_COLUMN_DU
             will look for surface pressure data in FILENAME.

        PTAU0 -> TAU0 value by which surface pressure data in
             PFILENAME is indexed.  If PTAU0 is omitted, then
             CTM_COLUMN_DU will use TAU0.  

        PTRACER -> Tracer number for the surface pressure data.
             Default is 1.  (For some GISS-CTM punch files, surface
             pressure is saved as tracer #0). 

        TROPFILENAME -> Name of the file containing the annual mean
             tropopause data for the GEOS-Chem model.  If TROPFILENAME
             is supplied, then columns will be computed from the
             surface up to the annual mean tropopause height.
             Otherwise, columns will be computed for the full
             vertical extent of the data.

        /DOUBLE -> If set, will return column sums as double
             precision.  Otherwise, will return column sums as
             single precision.

        MODELINFO -> Returns to the calling program the MODELINFO
             structure (i.e. output from CTM_TYPE) corresponding to 
             the data.

        GRIDINFO -> Returns to the calling program the GRIDINFO 
             structure (i.e. output from CTM_GRID) corresponding
             to the data.

        XMID -> Returns to the calling program the longitude centers
             in degrees for the extracted data block.
 
        YMID -> Returns to the calling program the latitude centers
             in degrees for the extracted data block.

        ZMID -> Returns to the calling program the altitude centers
             in # of levels for the extracted data block.
       
        /DU -> If set, will return column sums in Dobsun units.
	      Otherwise, will return column sums in molec/cm2. (jaf, 8/19/08)

        _EXTRA=e -> Picks up any extra keywords.


 OUTPUTS:
        RESULT -> a 2-D array containing the columns for TRACER
             in Dobson Units (DU).  1 DU = 2.69e16 molec/cm2.

 SUBROUTINES:
        Internal Subroutines:
        =============================================================
        CCD_GetAirMass (function)   CCD_Consistency_Check (function)
    

        External Subroutines Required:
        =============================================================
        CHKSTRU          (function)   CTM_BOXSIZE       (function)
        CTM_EXTRACT      (function)   CTM_GET_DATABLOCK (function)
        EXTRACT_FILENAME (function) 

 REQUIREMENTS:
        References routines in both GAMAP and TOOLS packages.

 NOTES:
        (1) An internal consistency check is now done to make sure
            the tracer data block is of the same model and resolution
            as the surface pressure and annual mean tropopause data blocks.

 EXAMPLE:
        Result = CTM_COLUMN_DU( 'IJ-AVG-$',          $
                                FileName='ctm.bpch'  $
                                Tracer=20,           $
                                Tau0=80304.0,        $
				 /DU )

             ; Returns O3 columns in DU from the file "ctm.bpch", 
             ; for March 1994 (TAU0 = 80304 for GEOS date 3/1/1994).

 MODIFICATION HISTORY:
        bmy, 26 Jul 1999: VERSION 1.00
        bmy, 20 Apr 2000: GAMAP VERSION 1.45
                          - renamed from "rvm_o3col"
                          - removed hardwiring, added comments
                          - added internal subroutine "CCD_Consistency_Check
                          - now can sum up to the annual mean tropopause
                            for GEOS model data blocks
        bmy, 30 Jul 2001: GAMAP VERSION 1.48
                          - bug fix: make sure to extract the same
                            lat/lon region for PS, tropopause heights
                            as we do for tracers
                          - added XMID, YMID, ZMID keywords to return
                            XMID, YMID, ZMID arrays from CTM_GET_DATABLOCK
                            to the calling program
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10
                          - Rewritten for hybrid grids, and to compute 
                            DU for a data block of less than global size
  jaf & phs, 18 Aug 2008: GAMAP VERSION 2.13
                          - added capability to read surface pressure in 
			     GEOS, which stores surface pressure as a 3-D
                            array called PEDGE-$
			   - added DU keyword so that default unit is
			     molec/cm2, and renamed "DU" output to "Column"

(See /n/home09/ryantosca/IDL/gamap2/gamap_util/ctm_column_du.pro)


CTM_CONVERT_UNIT

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
        CTM_CONVERT_UNIT 

 PURPOSE:
        Wrapper program for CONVERT_UNIT.PRO

 CATEGORY:
        GAMAP Utilities

 CALLING SEQUENCE:
        CTM_CONVERT_UNIT, Data [,Keywords] 

 INPUTS:
        DATA -> The data array (or value) on which to perform
             the unit conversion.  DATA will be converted.

 KEYWORD PARAMETERS:
        CNUM -> For hydrocarbons, CNUM is the following
             ratio: ( moles C / moles hydrocarbon ).
             CNUM is needed to convert from ppbC to ppbv.

     Keyword Parameters Passed to CONVERT_UNIT:
     ==========================================
        FROM_UNIT -> An individual unit to search and replace. 
             If not given, any unit will be converted to TO_UNIT, 
             as long as the current unit belongs to 
             the same category. 

        TO_UNIT -> An individual unit to convert to. If not given, 
             all units that are converted (see FROM_UNIT) will be 
             replaced by the standard SI unit of their category.

        For the individual unit and categories see FIND_UNIT 

        _EXTRA=e  -> Picks up any extra keywords for CTM_CONVERT_UNIT.

 OUTPUTS:
        RESULT -> Returns 1 if conversion was successful, 0 otherwise.

 SUBROUTINES:
        External Subroutines Required:
        ===============================
        CONVERT_UNIT
        CONVERT_MOLCM2_KG (function)
        CONVERT_KG_MOLCM2 (function)

 REQUIREMENTS:
        None

 NOTES:
        Will first convert ppbC to ppbv

 EXAMPLE:
        CTM_CONVERT_UNIT, Data, From='ppbC', To='ppbv', $
                          CNum=5, Result=Result

             ; converts Isoprene (5 mole C / 1 mole ISOP ) from
             ; parts per billion of Carbon (ppbC) to parts per
             ; parts per billion by volume of ISOP (ppbv).
             ; RESULT = 1 if unit conversion was successful.

 MODIFICATION HISTORY:
        bmy, 29 Sep 1998: VERSION 1.00
        bmy, 07 Oct 1998: VERSION 1.01
                          - Added unit conversion for mol/cm2 -> kg etc.. 
        mgs, 11 Nov 1998: - bug fix if seconds not passed
        bmy, 21 Jun 2002: GAMAP VERSION 1.51
                          - now recognize string "molec/cm2/s"
                          - updated comments, cosmetic changes
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10

(See /n/home09/ryantosca/IDL/gamap2/gamap_util/ctm_convert_unit.pro)


CTM_DATAINFO (FUNCTION)

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
        CTM_DATAINFO  (function)

 PURPOSE:
        Return information about available categories, tracers or 
        time steps in either a given or the global datainfo structure 
        array.

 CATEGORY:
        GAMAP Utilities, Structures

 CALLING SEQUENCE:
        RESULT = CTM_DATAINFO( [DIAGN] [,DATAINFO] [,keywords] )

 INPUTS:
        DIAGN -> A diagnostic number or category name for which
             information shall be returned on available tracers 
             or time steps. If not given, CTM_DATAINFO returns
             information about all available diagnostics instead.
 
        DATAINFO -> An optional subset of the global DataInfo 
             structure array. If given, the search will be 
             restricted to the data records contained in DATAINFO.

 KEYWORD PARAMETERS:
        /TRACER -> If set, CTM_DATAINFO returns all tracer numbers
             that are available with the given diagnostics. This
             keyword has no effect if no DIAGN is given.

        /TAU0 -> Returns information about all available time steps
             for a given diagnostics. This keyword has no effect if
             either DIAGN is not given or /TRACER is set.
    
        /TAU1 -> Same as TAU0, but for the end of the time step.

        If none of these keywords is set, CTM_DATAINFO returns the
        index values for the DATAINFO structure array that match
        the requested diagnostics.

        STATUS -> restrict search to: 0=unread data, 1=read data.
             Default is 2=no restriction

        /EXPAND -> For multilevel diagnostics, CTM_DATAINFO normally
             returns only the template (with the '$' character). Use
             this keyword to get all individual levels as well.

 OUTPUTS:
        Depending on the keywords and the DIAGN parameter, an array
        with diagmostics numbers, index values, tracer numbers, or 
        time steps is returned. 

 SUBROUTINES:
        External Subroutines Required:
        ====================================
        CTM_SELECT_DATA, CTM_DIAGINFO

 REQUIREMENTS:
        None

 NOTES:
        None

 EXAMPLE:
        ; Must read in some data first
        CTM_GET_DATA, 'IJ-AVG-$', TRACER=1, FILE=''

        ; print all tracers that are available for diag IJ-AVG-$
        PRINT, CTM_DATAINFO( 'IJ-AVG-$', /TRACER )

        ; print all time step endings for diagnostics IJ-AVG-$
        PRINT, CTM_DATAINFO( 'IJ-AVG-$', /TAU0 )

        ; print all diagnostics that are available in the file
        ; (or in all files previously read)
        PRINT, CTM_DATAINFO()

        ; print all record indices for diagnostics IJ-AVG_$
        PRINT, CTM_DATAINFO( 'IJ-AVG-$' )

 MODIFICATION HISTORY:
        mgs, 07 Oct 1998: VERSION 1.00
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10

(See /n/home09/ryantosca/IDL/gamap2/gamap_util/ctm_datainfo.pro)


CTM_DIAGINFO

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
        CTM_DIAGINFO

 PURPOSE:
        Return information about one or all of the diagnostic 
        used by GEOS-CHEM, GISS, or other CTM's.  

 CATEGORY:
        GAMAP Utilities, Structures

 CALLING SEQUENCE:
        CTM_DIAGINFO, DIAGN, DIAGSTRU [ , Keywords ]

 INPUTS:
        DIAGN -> Diagnostic category name for which to extract the 
             information.  To retrieve information about all CTM
             diagnostic categories use the /ALL_DIAGS keyword.

 KEYWORD PARAMETERS:
        /ALL_DIAGS -> Retrieves information about all diagnostics.

        CATEGORY -> Returns to the calling program the punch
             file category name of the requested diagnostic(s)

        FILENAME -> Name of the diaginfo file (default diaginfo.dat)
             The file will be searched in the current directory first, 
             then in the directory where CTM_DIAGINFO.PRO is located.
             If not found in either location, a standard data block is
             retrieved from this file.

        /FORCE_READING -> Read from the diaginfo file (specified in
             FILENAME) and overwrite the contents of the common block.

        MAXTRACER -> Returns to the calling program the maximum
             number of tracers stored in the requested diagnostic(s).
             NOTE: This is now only necessary for backwards 
             compatibility with the GISS-II ASCII punch files.

        OFFSET -> Returns to the calling program the offset constant 
             that is used to locate tracers in the "tracerinfo.dat"
             file.  OFFSET is needed to locate the proper index from
             the "tracerinfo.dat" file.

        SPACING -> Returns to the calling program the interval
             between diagnostic offsets.

 OUTPUTS:
        DIAGSTRU -> returns a structure or structure array with the 
             following tags:
             Category  : Category name for this diagnostic
             Offset    : Offset factor used in "tracerinfo.dat" file
             Spacing   : Spacing between diagnostic offsets 
             MaxTracer : Max # of tracers stored in this diagnostic

 SUBROUTINES:
        Internal Subroutines:
        =============================================
        CD_Is_MaxTracer (function)

        External Subroutines Required:
        =============================================
        FILE_EXIST   (function)   OPEN_FILE
        ROUTINE_NAME (funciton)   STRBREAK (function)

 REQUIREMENTS:
        Requires routines from the TOOLS package.

 NOTES:
        (1) At first call, the tracer information structure array is
        read from a file.  Thereafter, the information is stored in a 
        common block where it is accessible in subsequent calls.

 EXAMPLES:
        (1)
        CTM_DIAGINFO, 'BIOGSRCE', R
        PRINT, R.CATEGORY, ':', R.MAXTRACER, ':',R.OFFSET
        IDL prints "BIOGSRCE:           0:        4700"
 
             ; Returns a structure containing tags CATEGORY,
             ; MAXTRACER, OFFSET for the "BIOGSRCE" diagnostic.
             ; as listed in the file "diaginfo.dat".

        (2)
        CTM_DIAGINFO, /ALL, CATEGORY=CATEGORY
        PRINT, CATEGORY
        IDL prints "IJ-AVG-$ IJ-24H-$ IJ-INS-$ INST-MAP ..."

             ; Return information about all category names
             ; listed in the file "diaginfo.dat".

 MODIFICATION HISTORY:
        bmy, 19 May 1998: VERSION 1.00
                          - developed from CTM_TRACERINFO.PRO v. 2.0 by
                            Martin Schultz (08 May 1998)
                            see comments to CTM_TRACERINFO.PRO for 
                            modification history of that subroutine
        bmy, 20 May 1998: - removed SCALE and UNIT structure tags & keywords
                          - added OFFSET structure tag & keyword
        bmy, 27 May 1998: - changed "tracers" to "diagnostics" in 
                            print statement.
        mgs, 13 Aug 1998: - now returns only first diagnostics for a
                            given number.  This permits to keep old
                            and new diagnostics in one file and use
                            the old diagnostics by name.
                          - introduced extra search one level above 
                            current dir.
        mgs, 17 Aug 1998: - changed defaults vor void return
                          - diaginfo.dat: MAXTRACER meaning changed!
        bmy, 17 Nov 2003: GAMAP VERSION 2.01
                          - Removed INDEX and TYPE, they're obsolete
                          - Now use new file format for "diaginfo.dat"
                            which allows for 8-digit offset numbers
                          - Added internal function CD_IS_MAXTRACER
                          - No longer read defaults from internal datablock
                          - Added SPACING keyword
                          - Updated comments 
        bmy, 09 Mar 2006: GAMAP VERSION 2.05
                          - Use "./diaginfo.dat" as default in
                            order to facilitate reading in IDL 5.5-
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10
                          - Now use the FILE_WHICH routine to
                            locate the "diaginfo.dat" file
        phs, 17 Jul 2008: GAMAP VERSION 2.12
                          - Bug fix: only use FILE_WHICH if the 
                            FILENAME keyword isn't passed.

(See /n/home09/ryantosca/IDL/gamap2/gamap_util/ctm_diaginfo.pro)


CTM_DIFF

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
        CTM_DIFF

 PURPOSE:
        Computes absolute or relative differences between two CTM
        data blocks, and creates a new entry in the global DATAINFO
        structure.

 CATEGORY:
        GAMAP Utilities

 CALLING SEQUENCE:
        CTM_DIFF, DIAGN, [, Keywords ]

 INPUTS:
        DIAGN -> A diagnostic number or category name (see
             (CTM_DIAGINFO). A value of 0 (or an empty string)
             prompts processing of all available diagnostics.
             DIAGN can also be an array of diagnostic numbers or
             category names.

 KEYWORD PARAMETERS:
        FILE -> File name or list of file names containing the data 
             blocks to be differenced.  

        ILUN -> Logical unit number, or list of logical unit numbers
             of the files that contain the data blocks to be differenced.   

        TAU0 -> A time value or list of values to restrict the search.
             Default handling as with ILUN or TRACER. TAU0 superseeds
             /FIRST, /LAST or TAURANGE.

        TRACER -> Tracer ID number, or list of tracer ID numbers.  
             CTM_DIFF will difference the data blocks for diagnostic 
             DIAGN and tracer TRACER.

        /PERCENT -> If set, will compute the percent difference
             between two data blocks as 100 * ( DATA2 - DATA1 ) / DATA1.  
             Default is to compute the absolute difference DATA2 - DATA1.  

        NEWTRACER -> Returns to the calling program the tracer values
             for the data blocks, as read in from disk.

        NEWTAU -> Returns to the calling program the TAU0 values for
             the data blocks, as read in from disk.

        RANGE -> Returns the min & max difference values to the
             calling program.

        /MASK -> If set, the absolute % difference is return, with
             data below either thresholds (see pc_thr and diff_thr)
             set to a negative value, -99 .They are "masked", and can
             be set to a specific color in a plot (see ctm_plotdiff
             usage of the same keyword) or set to NaN for future
             analysis.
             
	 PC_THR, DIFF_THR : the %-Diff and Diff THResholds to mask data if
             /MASK is set.  Default values are 1% and 1e4.

 OUTPUTS:
        CTM_DIFF will append an entry to the global DATAINFO array of
        structures pertaining to the difference between the data
        blocks.

 OUTPUT KEYWORD:
 
        OUTLUN -> set this keyword to a variable name that will hold
             the LUN associated with the newly computed difference
             data.

        SUCCESS -> 0 by default, becomes 1 if MASK is set and all
             data are below the thresholds that define the MASK.


 SUBROUTINES:
        External Subroutines Requrired:
        =========================================================
        CTM_GET_DATA             CTM_MAKE_DATAINFO (function)
        CTM_GRID     (function)  GAMAP_CMN         (include file)
        INV_INDEX    (function)  YESNO             (function)
        CTM_DIAGINFO 

 REQUIREMENTS:
        References routines from GAMAP and TOOLS packages.

        Also, currently will only look at data blocks with the same
        tracer, since differencing two different tracers is not
        always that productive. 

 NOTES:
        (1) If DATA1 corresponds to the "old" data, and DATA2
            corresponds to the "new" data, then CTM_DIFF will 
            compute the following:
         
            Abs. Diff = ( new - old )
            % Diff    = ( new - old ) / old

        (2) The DATAINFO entries created by CTM_DIFF can be read into
            GAMAP with the /NOFILE option.  The ILUN values of these 
            data blocks will be negative, indicating derived data.

        (3) The call to CTM_REGRID probably does not work yet.
             Will get around to fixing that later...

 EXAMPLE:
        (1) Call CTM_DIFF to compute an absolute difference between
            two data blocks from two different punch files, at the
            same TAU0 value, for OH (DIAGN='CHEM-L=$', TRACER=1).
            
            FILE = [ 'ctm.bpch.v4-30', 'ctm.bpch.v4-31' ] 
            CTM_DIFF, 'CHEM-L=$', FILE=FILE, TRACER=1


        (2) Call CTM_DIFF to compute a relative difference between
            two data blocks from the same punch file, at two
            different TAU0 values, for tracer 1 (Radon).

            ILUN = 20
            TAU0 = [ 74472L, 74640L ]

            CTM_DIFF, 'IJ-AVG-$', ILUN=ILUN, TAU0=TAU0, $
                  TRACER=1, /Percent
 
 MODIFICATION HISTORY:
        bmy, 23 Apr 1999: VERSION 1.00
        mgs, 18 May 1999: - some bug fixes in error checks.
                          - regridding still not tested !!
        mgs, 10 Jun 1999: - bug fix for percent diference (indexing)
        bmy, 15 Sep 1999: GAMAP VERSION 1.43
                          - now use the GRIDINFO structure from the
                            global FILEINFO structure, if it exists.
                          - bug fix in call to CTM_GET_DATABLOCK
                          - updated comments
        bmy, 14 Jan 2000: GAMAP VERSION 1.44
                          - now allow comparision of two different
                            tracer numbers (e.g. for comparing two
                            simulations w/ different tracer indices)
                          - added error checking for size of the
                            FILE, ILUN, TAU0, TRACER keywords
                          - deleted obsolete code
        bmy, 26 Jan 2000: GAMAP VERSION 1.45
                          - now allow TAU0, FILE, ILUN, TRACER to have 
                            0 elements w/o generating an error message
        bmy, 15 Nov 2001: GAMAP VERSION 1.49
                          - Now make sure that NEWTRACER is not a 
                            multiple of 100, so that the tracer #
                            will be saved correctly to the global 
                            DATAINFO structure 
        bmy, 22 Apr 2002: GAMAP VERSION 1.50
                          - updated comments
        bmy, 19 Nov 2003: GAMAP VERSION 2.01
                          - Now get spacing between diagnostic
                            offsets from CTM_DIAGINFO
        bmy, 29 Jan 2004: - Added LEV keyword so that you can
                            select just a single level
                          - If we are just comparing a single level,
                            then do not test altitude dimensions
                            of the two data blocks.
        bmy, 16 Feb 2005: GAMAP VERSION 2.03
                          - now pass _EXTRA=e to CTM_GET_DATA 
        phs, 24 Oct 2006: GAMAP VERSION 2.05
                          - replace CTM_REGRID with CTM_REGRIDH
                          - pass _EXTRA=e to CTM_REGRIDH
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10
                          - added RANGE keyword for sending min/max
                            difference values to the calling program
        phs, 25 Sep 2009: GAMAP VERSION 2.13
                          - OUTLUN kwrd returns LUN associated with
                            computed difference
                          - /MASK is available to deals with absolute
                            %-age data and masked data below PC_THR
                            and/or DIFF_THR

(See /n/home09/ryantosca/IDL/gamap2/gamap_util/ctm_diff.pro)


CTM_DOSELECT_DATA (FUNCTION)

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
        CTM_DOSELECT_DATA (function)

 PURPOSE:
        Return indices for data blocks that match specific
        criteria.  This is an internal routine which is called
        by CTM_GET_DATA.  

 CATEGORY:
        GAMAP Internals

 CALLING SEQUENCE:
        INDEX = CTM_DOSELECT_DATA( DIAGN, USE_DATAINFO [, keywords ] )

 INPUTS:
        CATEGORY -> A string or string array with category names
            to search for. Multilevel categories can be expanded to
            a string array with the EXPAND_CATEGORY function.
            Usually, CTM_DOSELECT_DATA should be called with only
            one "logical" category at the time, i.e. only for
            multilevel diagnostics should it contain more than one
            element. Otherwise, the tracer offset may be wrong.

        USE_DATAINFO -> A valid DataInfo structure. No error checking 
            is performed.

        Both parameters are mandatory.

 KEYWORD PARAMETERS:
        ILUN -> A logical unit value or an array of logical unit
            values. Only records from corresponding files will be 
            returned. If ILUN is an undefined variable, information
            about all previously opened files will be returned,
            and ILUN will contain all logical unit numbers that 
            match the selection criteria.

        TRACER -> A tracer number or an array of tracer numbers to
            restrict the selection of data records. Default is to
            return information about all tracers.
            Tracer numbers less than 100 are automatically expanded
            to include the offset of certain diagnostics (see
            keyword TRCOFFSET and routine CTM_DIAGINFO). If TRACER is
            an undefined variable, all tracers that match the selection 
            criteria are returned.

        TRCOFFSET -> A tracer offset (multiple of 100) that will be
            added to TRACER. The search is performed for both,
            TRACER and TRACER+TRCOFFSET. (for tracer offsets see
            routine CTM_DIAGINFO and file diaginfo.dat)
 
        TAU -> A time value (tau0 !) or an array of time values
            to restrict the selection of data records. Default is to
            return information about all time steps. If TAU is an
            undefined variable, it will return all time steps that
            match the selection criteria.

        STATUS -> Restricts the data selection to
            Data that has not been read  (STATUS = 0)
            Data that has been read      (STATUS = 1)
            All data blocks              (STATUS = 2, default)
            If STATUS is 1, all pointers returned in DATA are tested
            for validity. Status will automatically be restricted 
            to range 0..1

        COUNT -> A named variable that will return the number of
            data blocks found with the given selection criteria

        MISSING -> If no records were found that match the selection 
            criteria, MISSING will return a string array with the 
            items that could not be matched (e.g. ['TRACER','ILUN']).
            If records were found, MISSING returns an empty string.

        SPACING -> Passes to CTM_DOSELECT_DATA the spacing between
            diagnostic offsets listed in "diaginfo.dat".  

 OUTPUTS:
        The function returns an (long) integer array that contains
        index values to all the data blocks that match the selection
        criteria. If no data is found, -1L is returned.

 SUBROUTINES:
        Uses IS_SELECTED function

 REQUIREMENTS:
        None

 NOTES:
        None

 EXAMPLE:
        See CTM_SELECT_DATA and CTM_READ_DATA source codes.

 MODIFICATION HISTORY:
        mgs, 19 Aug 1998: VERSION 1.00
        mgs, 07 Oct 1998: - added DEBUG keyword
        mgs, 22 Oct 1998: - now filters ilun, tracer, and tau
                            after finding matching records. This
                            was necessary to find the correct first
                            or last time step in CTM_GET_DATA.
                            Needs some more testing whether there are
                            side effects when TAU0 and ILUN or TRACER
                            are specified.
        mgs, 09 Nov 1998: - improved documentation
                          - default status now 2
                          - uses status field in use_datainfo instead of
                            ptr_valid function
                          - ILUN, TRACER and TAU only overwritten
                            if they are undefined variables
                          - added MISSING keyword
        mgs, 10 Nov 1998: - minor bug fix for status=1
        bmy, 19 Nov 2003: GAMAP VERSION 2.01
                          - added SPACING keyword to pass the
                            diagnostic spacing from CTM_DIAGINFO
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10

(See /n/home09/ryantosca/IDL/gamap2/internals/ctm_doselect_data.pro)


CTM_EXAMPLES

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
        CTM_EXAMPLES

 PURPOSE:
        Quick and dirty demonstration of various CTM_* routines

 CATEGORY:
        GAMAP Examples, GAMAP Utilities

 CALLING SEQUENCE:
        CTM_EXAMPLES

 INPUTS:
        None

 KEYWORD PARAMETERS:
        /PNG -> Set this switch to create PNG files from screen
             shots of examples generated by this program.

 OUTPUTS:
        None

 SUBROUTINES:
        External Subroutines Required:
        ===============================================
        OPEN_DEVICE           MULTIPANEL
        CTM_GET_DATA          GETMODELANDGRIDINFO
        TVMAP                 PAUSE
        CTM_PLOT              SCREEN2PNG
        NYMD2TAU (function)   CTM_OVERLAY

 REQUIREMENTS:
        None

 NOTES:
        Updated with the most recent GAMAP routines.

 EXAMPLE:
        CTM_EXAMPLES, /PNG

             ; Show example plots and create screenshot output
             ; as PNG files.

 MODIFICATION HISTORY:
        mgs, 20 Aug 1998: INITIAL VERSION
        mgs, 22 Oct 1998: - adapted for new use of CTM_GET_DATA
                            some more comments
        mgs, 26 Oct 1998: - attached a few more comments about extended 
                            use of ctm_get_data at end
        mgs, 18 Nov 1998: - added call to CTM_MAKE_DATAINFO
        bmy, 06 Oct 2006: GAMAP VERSION 2.05
                          - Updated examples w/ newest GAMAP routines
                          - Added examples w/ CTM_OVERLAY and
                            FIND_CELLS_BY_COUNTRY
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10
                          - now uses FILE_WHICH to find ctm.bpch.examples

(See /n/home09/ryantosca/IDL/gamap2/examples/ctm_examples.pro)


CTM_EXTRACT (FUNCTION)

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
        CTM_EXTRACT (function)

 PURPOSE:
        Extracts a block of data from a 3-D CTM data cube.

 CATEGORY:
        GAMAP Utilities, GAMAP Data Manipulation

 CALLING SEQUENCE:
        CTM_EXTRACT, DATA, MODELINFO, GRIDINFO [,Keywords]

 INPUTS:
        DATA -> The data cube from which to extract a region.
             DATA must be 3-dimensional (e.g. lon-lat-alt, or 
             lon-lat-tracer, etc).

 KEYWORD PARAMETERS:
        MODELINFO -> The MODELINFO structure returned from function 
             CTM_TYPE.  

        GRIDINFO -> The GRIDINFO structure returned from function
             CTM_GRID.

        AVERAGE -> Bit flag indicating the dimensions over which to
             average the data:
                1 :  longitudinal
                2 :  latitudinal
                4 :  vertical
             These values can be combined. E.g., to average over 
             longitude and latitude use 3. A bit set in AVERAGE 
             superseeds the corresponding bit in TOTAL (see below).
 
        TOTAL -> Bit flag indicating the dimensions over which
             to sum the data:
                1 :  longitudinal
                2 :  latitudinal
                4 :  vertical
             These values can be combined. E.g., to integrate over
             longitude and latitude use 3. A bit set in AVERAGE
             superseeds the corresponding bit in TOTAL (see above).

        /INDEX -> If set, will interpret LAT, LEV, and LON as index 
             arrays.  If not set, will interpret LAT, LEV, and LON as 
             ranges (i.e. two-element vectors containing min and max values).

        LAT -> An index array of latitudes *OR* a two-element vector 
             specifying the min and max latitudes to be included in
             the extracted data block.  Default is [ -90, 90 ].

        LEV -> An index array of sigma levels *OR* a two-element vector 
             specifying the min and max sigma levels to be included
             in the extracted data block.  Default is [ 1, GRIDINFO.LMX ].

        LON -> An index array of longitudes *OR* a two-element vector 
             specifying the min and max longitudes to be included in
             the extracted data block.  Default is [ -180, 180 ].

        ALTRANGE -> A vector specifying the min and max altitude 
             values (or a scalar specifying a single altitude) to
             be included in the extracted data block.

        PRANGE -> A vector specifying the min and max pressure levels 
             (or a scalar specifying a single pressure level) to be
             included in the extracted data block.

        WE -> Returns to the calling program the index array of longitudes 
             for the extracted data region, ordered from west to east.

        SN -> Returns to the calling program the index array of latitudes
             for the extracted data region, ordered from South to North.
 
        UP -> Returns to the calling program the index array of vertical  
             levels for the extracted data region, ordered from surface
             to top.

        DIM -> A named variable will return the new dimension information 
             of the data block after averaging or totaling.

        _EXTRA=e   -> Picks up extra keywords for CTM_INDEX.

 OUTPUTS:
        X, Y, Z -> Arrays of latitude, longitude, or altitude values 
             corresponding to the the 1st, 2nd, and 3rd dimensions of 
             the DATA array, respectively.

 SUBROUTINES:
        CTM_INDEX 
        DEFAULT_RANGE (function)

 REQUIREMENTS:
        Uses GAMAP package subroutines.

 NOTES:
        (1) CTM_EXTRACT returns the extracted data region as 
        the function value.

        (2) Assumes a 3-D data cube as input, of dimensions (lon, lat,
        alt), or for some diagnostics (lon, lat, "tracer" number).

        (3) In the calling program, CTM_TYPE and CTM_GRID must be 
        called to compute the MODELINFO and GRIDINFO structures,
        which can then be passed to CTM_EXTRACT.

        (4) If any of the LAT, LON, LEV, ALTRANGE, PRANGE keywords are
        explicity specified, then CTM_EXTRACT will return to the
        calling program their original, unmodified values.  If any
        of these are not explicitly specified , then CTM_EXTRACT 
        will return to the calling program default values.  

 EXAMPLE:
        (1)
        MODELINFO  = CTM_TYPE( 'GEOS4', RES=4 )
        GRIDINFO   = CTM_GRID( MODELINFO )
        DATAREGION = CTM_EXTRACT( DATACUBE,                   $
                                  MODELINFO=MODELINFO,        $
                                  GRIDINFO=GRIDINFO           $
                                  LON=[-180,0], LAT=[-30,30], $ 
                                  LEV=[1,10] )

               ; Extracts from a GEOS-4 4x5 data cube a region 
               ; delimited by longitude = [-180, 0], 
               ; latitude = [-30, 30], for levels 1 to 10.

        (2)
        LON = INDGEN( 36 )
        LAT = INDGEN( 16 ) + 15
        LEV = INDGEN( 10 ) 
        MODELINFO  = CTM_TYPE( 'GEOS4' )
        GRIDINFO   = CTM_GRID( MODELINFO )
        DATAREGION = CTM_EXTRACT( DATACUBE,            $
                                  MODELINFO=MODELINFO, $
                                  GRIDINFO=GRIDINFO,   $
                                  /INDEX,  LON=LON,    $
                                  LAT=LAT, LEV=LEV )

               ; Extracts same data region as in Example (1) but 
               ; here passes explicit index arrays instead of ranges.

 MODIFICATION HISTORY:
        bmy, 16 Sep 1998: VERSION 1.00
        bmy, 17 Sep 1998: - now extracts data from data cube one 
                            dimension at a time to avoid errors
        bmy, 18 Sep 1998: VERSION 1.01
                          - INDEX, SN, WE, UP keywords added
                          - LATRANGE, LONRANGE, LEVRANGE renamed
                            to LAT, LON, LEV (since they may now 
                            contain arrays and not just ranges).
        mgs, 21 Sep 1998: - some more error checking
                          - removed MinData and MaxData 
        bmy and mgs, 22 Sep 1998: VERSION 1.02
                          - added AVERAGE and TOTAL keywords
        bmy, 24 Sep 1998: VERSION 1.03
                          - Now returns original values of LAT, LON, 
                            LEV, ALTRANGE, and PRANGE if those keywords
                            are specified.  Otherwise returns
                            defaults.
        MGS, 29 SEP 1998: - Introduced new DEFAULT_RANGE function.
        bmy, 06 Oct 1998: - fixed bug: now S = size( NEWDATA )
        bmy, 08 Oct 1998: VERSION 1.04
                          - MODELINFO and GRIDINFO are now keywords
                          - added X, Y, and Z as parameters
        bmy, 11 Feb 1999: - updated comments
        bmy, 19 Feb 1999: VERSION 1.05
                          - added FIRST keyword so that the values of
                            THISDATAINFO.FIRST can be passed from the
                            calling routine.
                          - now call ADJ_INDEX to adjust the WE,
                            SN, and UP index arrays for data blocks
                            that are less than global size.
                          - added DEBUG keyword
        mgs, 16 Mar 1999: - cosmetic changes
        mgs, 02 Apr 1999: - bug fixes that prevented use with 2D fields
                            (e.g. EPTOMS data)
        mgs, 21 May 1999: - now catches error in multitracer diagnostics
                            when user requests a level beyond LMX.
        qli, 26 May 1999: - "max(newlev) ge" corrected to "gt"
        bmy, 15 Sep 1999: VERSION 1.43
                          - removed bugs that caused data blocks to
                            always have MODELINFO.NTROP vertical
                            layers
        bmy, 04 Dec 2000: GAMAP VERSION 1.47
                          - add code for future bug fix
        bmy, 24 Apr 2001: - bug fix: now can handle longitudes
                            greater than 180 degrees
        bmy, 06 Jun 2001: - bug fix: Test if LON exists before
                            assigning it to NEWLON.
        bmy, 30 Jul 2001: GAMAP VERSION 1.48
                          - bug fix: now extract proper latitude range
                            for data blocks smaller than global size
        bmy, 26 Jun 2002: GAMAP VERSION 1.51
                          - Default value of FIRST is now [1,1,1], 
                            since this has to be in Fortran notation.
                          - also do error checking on FIRST near
                            the beginning of the program.
        bmy, 15 Nov 2002: GAMAP VERSION 1.52
                          - now can handle total/average for MOPITT grid
        bmy, 23 Aug 2004: GAMAP VERSION 2.03
                          - now can handle single-point data blocks
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10
        bmy, 19 Nov 2007: GAMAP VERSION 2.11
                          - Updated comments
        bmy, 10 Dec 2007: GAMAP VERSION 2.12
                          - Now pad ALTRANGE and PRANGE to 2 elements
                            if they are passed w/ one element
        bmy, 13 Aug 2009: GAMAP VERSION 2.13
                          - Bug fix: now compute DEF_X_RANGE from the
                            grid edges for computing NEWLON.  Now
                            also works for nested grids.
  phs & bmy, 13 Oct 2009: - Bug fix: now account for ranges that
                            straddle the date line when computing
                            DEF_X_RANGE
        ccc, 21 Oct 2009: - Bug fix when PRange is passed.
        bmy, 20 Mar 2017: GAMAP VERSION 2.19
                          - Now make sure that WE, SN, UP are converted
                            from Fortran to IDL notation properly
                            when /INDEX is specified.

(See /n/home09/ryantosca/IDL/gamap2/gamap_util/ctm_extract.pro)


CTM_GETDEFAULTSTRUCTURES

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 NAME:
        CTM_GETDEFAULTSTRUCTURES

 PURPOSE:
        Return default values for FileInfo and DataInfo for
        subsequent analysis. The defaults are taken from the
        global common block defined in gamap_cmn.pro

 CATEGORY:
        GAMAP Internals, Structures

 CALLING SEQUENCE:
        CTM_GETDEFAULTSTRUCTURES, FileInfo, DataInfo, result=result

 INPUTS:
        FILEINFO -> A named variable that will contain the global
            FileInfo structure array, i.e. information about all
            files that have been opened.

        DATAINFO -> A named variable that will contain the global
            DataInfo structure array, i.e. information about all
            data records that have been read from the headers of 
            all opened CTM files.

 KEYWORD PARAMETERS:
        RESULT -> returns 1 if assignment was successful, 0 otherwise.

 OUTPUTS:
        None

 SUBROUTINES:
        External Subroutines Required
        ==============================
        GAMAP_CMN

 REQUIREMENTS:
        Requires routines from the GAMAP package.

 NOTES:
        None

 EXAMPLE:
        CTM_GETDEFAULTSTRUCTURES, $
            FileInfo, DataInfo, result=result

        if (not result) then return

        ; the current state of the global FileInfo and DataInfo 
        ; structures will be copied into FileInfo and DataInfo

 MODIFICATION HISTORY:
        mgs, 20 Aug 1998: VERSION 1.00
        mgs, 21 Sep 1998: - changed gamap.cmn to gamap_cmn.pro
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10

(See /n/home09/ryantosca/IDL/gamap2/internals/ctm_getdefaultstructures.pro)


CTM_GETWEIGHT

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
        CTM_GETWEIGHT

 PURPOSE:
        Computes the "mapping weights" for regridding data from
        a "fine" CTM grid to a CTM grid of equal or coarser 
        horizontal resolution.

 CATEGORY:
        Regridding

 CALLING SEQUENCE:
        CTM_GETWEIGHT, OLDGRID, NEWGRID, WEIGHT, XX_IND, YY_IND [, Keywords ]

 INPUTS:
        OLDGRID -> GRIDINFO structure (use ctm_grid to create one) 
             which defines the old ("fine") grid.

        NEWGRID -> GRIDINFO structure (use ctm_grid to create one) 
             which defines the new ("coarse") grid.
 

 KEYWORD PARAMETERS:
        WEIGHTFILE (optional) -> Name of the file to which WEIGHT,
             XX_IND, and YY_IND will be written.  If WEIGHTFILE is
             not given, then

        WEIGHTFORMAT (optional) -> Specify the format string used to
             save the mapping weights to WEIGHTFILE.  For high-res grids,
             you may need to specify more than the default 2 decimal 
             precision.  Default value is '(3x,12f6.2)'.

 OUTPUTS:
        WEIGHT -> Array of mapping weights which defines the fraction
             of each "fine" grid box that fits into each "coarse" 
             grid box.

        XX_IND -> Array of "longitude" grid box indices of the "fine" 
             grid boxes that fit into each "coarse" grid box.  

        YY_IND -> Array of "latitude" grid box indices of the "fine" 
             grid boxes that fit into each "coarse" grid box.

 SUBROUTINES:
        External Subroutines Required:
        ================================

 REQUIREMENTS:
        References routines from both GAMAP and TOOLS packages.

 NOTES:
        (1) This routine was adapted from CTM_REGRID.  It is
            sometimes computationally expedient to compute the
            mapping weights once for the entire horizontal grid 
            and save them to a file for future use.
            
        (2) Right now this only works in regridding from a "fine" 
            grid to a grid of equal horiziontal resolution (i.e. with
            shifted grid boxes) or coarser horizontal resolution.

 EXAMPLE:
        OLDTYPE = CTM_TYPE( 'GENERIC', RES=1, HALFPOLAR=0, CENTER180=0 )
        OLDGRID = CTM_GRID( OLDTYPE, /NO_VERTICAL )
        NEWTYPE = CTM_TYPE( 'GEOS4', RES=4 )
        NEWGRID = CTM_GRID( NEWTYPE, /NO_VERTICAL )

        CTM_GETWEIGHT, OLDGRID, NEWGRID, WEIGHT, XX_IND, YY_IND, $
             WEIGHTFILE = 'weights.1x1.to.geos1.4x5']

             ; Precomputes the mapping weights for regridding a
             ; 1 x 1 grid to the GEOS-1 4 x 5 grid, and saves them
             ; to an ASCII file named "weights.1x1.to.geos1.4x5"

 MODIFICATION HISTORY:
        bmy, 11 Aug 2000: VERSION 1.01
                          - adapted from CTM_REGRID
        bmy, 21 Jan 2003: VERSION 1.02
                          - Added fix for GEOS 1 x 1.25 grid
        bmy, 04 May 2006: GAMAP VERSION 2.05
                          - Added fix for GENERIC 2.5 x 2.5 grid
        bmy, 29 Jun 2006: - Added fix for GEOS 1x1 -> GENERIC 1x1 
  bmy & phs, 04 Oct 2007: GAMAP VERSION 2.10
                          - added fix for GENERIC 0.5 x 0.5 grid
                          - general fix for over-the-dateline cases
        bmy, 26 Sep 2008: GAMAP VERSION 2.13
                          - Add WEIGHTFORMAT keyword to specify more
                            decimal places of precision if need be

(See /n/home09/ryantosca/IDL/gamap2/regridding/ctm_getweight.pro)


CTM_GET_DATA

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 NAME:
        CTM_GET_DATA

 PURPOSE:
        Retrieve specific data records from CTM output files.
        Opening files, parsing header information, and loading
        of data are handled transparently and can be 
        controlled by various keywords. The routine returns a
        subset of the global DATAINFO structure that matches the
        requested category and (optional) tracer and time step(s).

        This routine should be called *whenever* you want to 
        access data and you are not sure that it has been 
        loaded previously. It provides the general user-interface
        for GAMAP (the Global Atmospheric Model output Analysis 
        Package). 

        For the future, a widget interface to this routine is 
        planned.

 CATEGORY:
        GAMAP Utilities, GAMAP Data Manipulation

 CALLING SEQUENCE:
        CTM_GET_DATA, DATAINFO [,DIAGN] [,keywords]

 INPUTS:
        DIAGN -> A diagnostic number or category name (see
             (CTM_DIAGINFO). A value of 0 (or an empty string)
             prompts processing of all available diagnostics.
             DIAGN can also be an array of diagnostic numbers or
             category names.

 KEYWORD PARAMETERS:
        FILENAME -> (optional) If FILENAME is a fully qualified file path
             the specified file is opened without user interaction.
             If filename is empty or contains wildchards (*,?), a
             pickfile dialog will be displayed.
             If FILENAME is a named variable it will contain the full
             file path upon return so that a subsequent call to
             CTM_GET_DATA with the same FILENAME argument will not prompt
             another file selection dialog.
                If the FILENAME keyword is present, CTM_GET_DATA
             will restrict it's scope to records from the selected
             is file (even if FILENAME contains an empty string, it will 
             restrict the scope of the search!).
                If the file is found in the global FILEINFO structure or
             the USE_FILEINFO structure (i.e. it has been opened 
             previously), then it will not be parsed again; instead the
             data records are returned from memory.
                The data itself is loaded transparently via 
             CTM_RETRIEVE_DATA.

        ILUN -> An optional value or array of logical unit numbers. If
             given, the search is restricted to data from the specified
             files. Default is to use all files (unless the FILENAME
             keyword is present). If an undefined variable
             is passed into ILUN, information about all accessible files
             in the global FILEINFO structure (or USE_FILEINFO) is returned.

        TRACER -> A tracer ID number or a list of those. If given, the
             search is restricted to those tracers. Default is to use all 
             tracers. If an undefined variable is passed into TRACER, 
             and one specific diagnostics is requested with DIAGN,
             information about all accessible tracers in the global
             DATAINFO structure or USE_DATAINFO structure or the
             DATAINFO structure associated with a specific file is returned.

        TAU0 -> A time value or list of values to restrict the search.
             Default handling as with ILUN or TRACER. TAU0 superseeds
             /FIRST, /LAST or TAURANGE.

        TAURANGE -> A 2-element vector containing the first and last tau0
             value to look for. 

        /FIRST, /LAST -> extract first or last time step that is stored for
             the selected diagnostics, ilun, and tracer. Only one can be 
             be active at a time. /LAST superseeds /FIRST.

        INDEX -> A named variable that will contain the indices of the 
             records in USE_DATAINFO that match the selection criteria.
             You can test INDEX[0] ge 0 in order to see if CTM_GET_DATA has
             been successful although it is now recommended to test for
             n_elements(DATAINFO) eq 0. 
                The INDEX keyword is useful if you want to change the
             information contained in the selected DATAINFO structures
             globally.

        USE_FILEINFO -> (optional) If provided, CTM_GET_DATA will 
             restrict its search to only the files that are
             contained in USE_FILEINFO which must be a FILEINFO 
             structure array. Default is to use the global information 
             (see gamap_cmn.pro).
             If an undefined named variable is provided in USE_FILEINFO,
             it will either contain the global FILEINFO structure array 
             or the FILEINFO record of the specified file.
             USE_FILEINFO must contain entries for all logical unit numbers
             that are used in USE_DATAINFO.

        USE_DATAINFO -> (optional) Restrict search to records contained
             in USE_DATAINFO which must be a DATAINFO structure array. 
             If an undefined named variable is provided in USE_DATAINFO,
             it will either contain the global DATAINFO structure array 
             or all DATAINFO records of the specified file.
             See also USE_FILEINFO.

        /INTERNAL_USE -> Set this keyword if you want to prevent a call
             to CTM_OPEN_FILE, but instead abort in case of undefined 
             (global) FILEINFO or DATAINFO structures.

 OUTPUTS:
        DATAINFO -> An array of DATAINFO records that match the selected 
             criteria. You can then simply loop over 
             0..n_elements(DATAINFO)-1 to access all data records and 
             extract the data as *(DATAINFO[i].data).
             DATAINFO will be undefined if no records are found!!
             Always test for  IF (n_elements(DATAINFO) eq 0) ... !
             NOTE: Alternatively you can return the INDEX to the selected
             data records in the global (or USE_) datainfo structure array
             with the INDEX keyword. This may in some cases eliminate the
             need to make a local copy of the selected DATAINFO records. 

 SUBROUTINES:
       pro reopen_all_files,fileinfo
       (needed in order to get free unit numbers)

       pro make_compound_datainfo,DataInfo,category,ilun,tracer,tau0,tau1
       (make compound structure for multilevel or multitracer diagnostics)

       pro update_tracer_datainfo,datainfo,traceroffset
       (enter tracer information into global datainfo structure)

 REQUIREMENTS:
       Several ctm_* routines are used
       Also uses UNDEFINE (by D. Fanning)

 NOTES:
       Please test rigorously. In case of read errors, try using CTM_OPEN_FILE
       with the /PRINT keyword.

       If your model output (ASCII punch file) does not contain the
       dimensional information about each data block, it may cause problems
       for diagnostics that do not contain 72x46 elements.
       It's defintively a good idea to implement this little change *NOW* !

       Outline of this procedure:
       - get all data records that match selection criteria
       - create "compound" datainfo structures for multilevel and
         multitracer diagnostics (those hold 3D data blocks)
       - read data for all selected compound structures unless only
         status information requested

 EXAMPLE:
       See CTM_EXAMPLES
       

 MODIFICATION HISTORY:
        mgs, 20 Aug 1998: VERSION 1.00
        mgs, 21 Sep 1998: - changed gamap.cmn to gamap_cmn.pro
        mgs, 22 Sep 1998: - changed to accomodate usage of 
                            tracer information
        mgs, 22 Oct 1998: - old FILEINFO and DATAINFO parameters now
                            keywords USE_..., new DATAINFO parameter
                            returns selected subset of records.
                          - print statements replaced with message
                          - DEBUG messages improved
                          - catch cancelled file open dialog
        mgs, 26 Oct 1998: - datainfo now undefined at start
                          - allows for multiple categories
                          - ilun, tracer, tau0 keyword variables renamed
                            as sel_... in order to preserve them
        mgs, 04 Nov 1998: - sel_tracer now expanded to include offsets
        mgs, 10 Nov 1998: VERSION 3.0 
                          - major update! Program structure much more
                            straightforward!
        mgs, 12 Nov 1998: - bug fixes for simple diagnostics (line 732)
                            and finding offset tracers (in update_...)
                            replaced tracer by (tracer mod 100) in 3 places
        mgs, 19 Nov 1998: - bug fix with scale factor. Didn't get globally
                            updated because it was linked to unit. Need a
                            more generic global update procedure !
        mgs, 03 Dec 1998: - yet another bug fix in reopen files: needed
                            to test for negative ilun before fstat
        bmy, 21 Jan 1999: - added outer parentheses to the FORMAT
                            descriptor (255(I4,1x)) to avoid errors
        mgs, 17 Feb 1999: - bug fix for simple diagnostics: needed
                            to add dummy value to compound array.
        mgs, 16 Mar 1999: - catch error in tracerinfo.dat (more than one
                            tracer with same number)
                          - error in update_tracer... should have been
                            fixed. Some more debug output added for 
                            testing.
        mgs, 23 mar 1999: - set vertical dimension to -1 for new compound
                            datainfo records
        mgs, 24 May 1999: - updated filetype info
        mgs, 02 Jun 1999: - added retall statement after error
                            message
        bmy, 23 Nov 1999: - added /SMALLCHEM keyword for CTM_TRACERINFO
        bmy, 27 Sep 2001: GAMAP VERSION 1.49
                          - Set F77=1 for filetype 4 (DAO met fields)
                          - Now reference function LITTLE_ENDIAN
                          - Swap endian in OPEN_FILE if reading data
                            on a little-endian machine (e.g. PC) 
        bmy, 19 Nov 2003: GAMAP VERSION 2.01
                          - now test valid diagnostics using 
                            DIAGSTRU[*].CATEGORY and not DIAGSTRU[*].INDEX
                          - removed /SMALLCHEM keyword, it's obsolete
                          - Now recognizes binary files as having
                            FILETYPE values between 100 and 200
                          - Removed /SMALLCHEM flag, it's obsolete
                          - Now uses diagnostic spacing from CTM_DIAGINFO
                            and pass this to UPDATE_TRACER_DIAGINFO
        bmy, 11 Feb 2004: GAMAP VERSION 2.01a
                          - Internal routine MAKE_COMPOUND_DATAINFO
                            now passes SPACING from CTM_DIAGINFO
                            to routine CTM_DOSELECT_DATA
        bmy, 27 Oct 2004: GAMAP VERSION 2.03
                          - added QUIET keyword to suppress printing
                            information about retrieved tracers
        bmy, 06 Feb 2006: GAMAP VERSION 2.04
                          - Bug fix: use DIALOG_PICKFILE to get file name
                            before calling CTM_OPEN_FILE.  This is necessary
                            because the tests for certain file types requires
                            the file name to be known ahead of time.
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10
                          - now passes _EXTRA keyword to
                            CTM_OPEN_FILE. This allows to read nested 
                            met (GMAO) files by using /NA or /CHINA
  bmy & phs, 20 Nov 2007: GAMAP VERSION 2.11
                          - If FILENAME is not defined, then the value
                            of the filename selected via dialog box
                            will be passed back to the calling program.

 KNOWN BUGS OR WEAKNESSES:
        - handling of USE_DATAINFO and USE_FILEINFO is not carried 
          through all lower level subroutines, i.e. they may be replaced
          by *pGlobal... in some occasions. Since USE_... should always
          be a subset of *pGlobal..., no serious errors are expected
          from this weakness. 

        - known bug in update_tracer_datainfo, see comment in routine.

(See /n/home09/ryantosca/IDL/gamap2/gamap_util/ctm_get_data.pro)


CTM_GET_DATABLOCK

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
        CTM_GET_DATABLOCK

 PURPOSE:
        Extracts a data block from a CTM punch file.
        (Wrapper program for CTM_GET_DATA and CTM_EXTRACT.)

 CATEGORY:
        GAMAP Utilities, GAMAP Data Manipulation

 CALLING SEQUENCE:
        SUCCESS = CTM_GET_DATABLOCK(DATA [,DIAGN] [,Keywords])

 INPUTS:
        DIAGN -> A diagnostic number or category name (see
             (CTM_DIAGINFO). This must uniquely identify a
             specific data type.  DIAGN is passed to CTM_GET_DATA


 KEYWORD PARAMETERS:
     Keywords that are passed to CTM_GET_DATA:
     =========================================
        FILENAME   -> Name of the file to open.  FILENAME is passed
                      to CTM_GET_DATA.  CTM_GET_DATA will return
                      the full path name, which is then returned
                      to the calling program.

        USE_FILEINFO -> (optional) If provided, CTM_GET_DATA will 
             restrict its search to only the files that are
             contained in USE_FILEINFO which must be a FILEINFO 
             structure array. Default is to use the global information 
             (see gamap_cmn.pro).
             If an undefined named variable is provided in USE_FILEINFO,
             it will either contain the global FILEINFO structure array 
             or the FILEINFO record of the specified file.
             USE_FILEINFO and USE_DATAINFO must be consistent, and should
             either both be used or omitted. However, it is
             possible to provide the global FILEINFO structure 
             (or nothing) with a local subset of DATAINFO.

        USE_DATAINFO -> (optional) Restrict search to records contained
             in USE_DATAINFO which must be a DATAINFO structure array. 
             If an undefined named variable is provided in USE_DATAINFO,
             it will either contain the global DATAINFO structure array 
             or all DATAINFO records of the specified file.
             See also USE_FILEINFO.

     Keywords that are passed to CTM_EXTRACT:
     ========================================
        AVERAGE -> Bit flag to average over certain dimensions
             (see CTM_EXTRACT)

        TOTAL -> Bit flag to sum over certain dimensions 
             (see CTM_EXTRACT)

        /INDEX -> If set, will interpret LAT, LEV, and LON as index 
             arrays.  If not set, will interpret LAT, LEV, and LON as 
             ranges (i.e. two-element vectors containing min and max values).

        LAT -> An index array of latitudes *OR* a two-element vector 
             specifying the min and max latitudes to be included in
             the extracted data block.  Default is [ -90, 90 ].

        LEV -> An index array of sigma levels *OR* a two-element vector 
             specifying the min and max sigma levels to be included in
             the extracted data block.  Default is [ 1, GRIDINFO.LMX ].

        LON -> An index array of longitudes *OR* a two-element vector 
             specifying the min and max longitudes to be included in
             the extracted data block.  Default is [ -180, 180 ].

        ALTRANGE -> A vector specifying the min and max altitude
             values to be included in the extracted data block.

        PRANGE -> A vector specifying the min and max pressure levels 
             to be included in the extracted data block.

     Other keywords:
     ===============
        XMID, YMID, ZMID -> Arrays of values (e.g. latitude,
             longitude, or altitude) for the 1st, 2nd, and 3rd
             dimensions of the DATA array, respectively.  
             NOTE: These are *NOT* index arrays.

        THISDATAINFO -> Returns the DATAINFO structure for the
             selected data block.

        MODELINFO -> Returns to the calling program the model information 
             structure created by CTM_TYPE.
                      
        GRIDINFO -> Returns to the calling program the grid information  
             structure created by CTM_GRID.

        WE -> Returns to the calling program the index array of longitudes
             for the extracted data region, ordered from west to east.

        SN -> Returns to the calling program the index array of latitudes
             for the extracted data region, ordered from South to North 
 
        UP -> Returns to the calling program the index array of vertical
             levels for the extracted data region, ordered from surface 
             to top.

        PSURF -> Surface pressure to be used for the conversion from
             sigma layers to pressure and altitude.  For defaults 
             see function CTM_TYPE.

       _EXTRA=e -> Picks up any extra keywords for CTM_GET_DATA
              and CTM_EXTRACT.
 
 OUTPUTS:
        SUCCESS -> Returns 1 if successful or 0 otherwise.
 
        DATA -> A 2D or 3D data array

 SUBROUTINES:
        External Subroutines Required:
        ==============================
        CTM_GET_DATA
        CTM_GRID    (function)
        CTM_EXTRACT (function)

 REQUIREMENTS:
        None

 NOTES:
        (1) CTM_GET_DATABLOCK returns the extracted data block as the 
        function value.

        (2) CTM_GET_DATABLOCK is meant to be called whenever you need
        to extract data from a punch file.  If the punch file needs
        to be opened, CTM_GET_DATABLOCK will do that automatically
        (via CTM_GET_DATA).  

 EXAMPLE:
   FILENAME  = '~/amalthea/CTM4/run/ctm.pch'
   LAT       = [  -90,  90 ]
   LON       = [ -180, 180 ]
   LEV       = 1
   SUCCESS   = CTM_GET_DATABLOCK( DATA, 'IJ-AVG-$',                 $
                           XIND=XMID, YIND=YMID, ZIND=ZMID,         $
                           THISDATAINFO=THISDATAINFO,               $
                           TRACER=1,           FILENAME=FILENAME,   $
                           GRIDINFO=GRIDINFO,  MODELINFO=MODELINFO, $
                           LEV=LEV,            LAT=LAT,             $
                           LON=LON,            WE=WE,               $
                           SN=SN,              UP=UP )

   IF ( NOT SUCCESS ) THEN RETURN, 0

            ; gets a data block for the IJ-AVG-$ (ND45) diagnostic,
            ; for the first tracer, at the first timestep, with the 
            ; given latitude, longitude, and sigma level ranges.  
            ; Returns FILEINFO, DATAINFO, THISDATAINFO, WE, SN, UP, 
            ; XMID, YMID, and ZMID to the calling program.

 MODIFICATION HISTORY:
        bmy, 16 Sep 1998: VERSION 1.00
        bmy, 17 Sep 1998: - added FILENAME keyword, so that the file
                            name can be passed back to the calling
                            program. 
        bmy, 18 Sep 1998: VERSION 1.01
                          - now compatible with CTM_EXTRACT v. 1.01
                          - INDEX, SN, WE, UP keywords added
                          - LATRANGE, LONRANGE, LEVRANGE renamed
                            to LAT, LON, LEV (since they may now 
                            contain arrays and not just ranges).
        mgs, 21 Sep 1998: VERSION 1.02
                          - more error checking
                          - added PSurf keywords
                          - frees gridinfo pointer before re-assignment
                          - removed MinData and MaxData
        bmy, 22 Sep 1998: - Now pass AVERAGE and TOTAL keywords to
                            CTM_EXTRACT
        mgs, 22 Sep 1998: - added THISDATAINFO keyword
        bmy, 24 Sep 1998: - added FORWARD_FUNCTION for CTM_GRID
                            and CTM_EXTRACT
        bmy, 08 Oct 1998: VERSION 1.03
                          - FILEINFO and DATAINFO are now keywords
                          - now returns X, Y, and Z as parameters
        bmy, 03 Nov 1998: VERSION 1.04
                          - compatible with new CTM_GET_DATA routine
                          - now pass FILEINFO and DATAINFO structures 
                            via USE_FILEINFO and USE_DATAINFO keywords
        mgs, 10 Nov 1998: - once more adapted to changes in CTM_GET_DATA
                          - now extracts locally used FILEINFO structure
        bmy, 11 Feb 1999: VERSION 1.05
                          - updated comments
        bmy, 19 Feb 1999: - Renamed XIND, YIND, ZIND to XMID, YMID,
                            and ZMID, since these are not index
                            arrays, but the actual longitude,
                            latitude, or altitude values for each
                            dimension of the DATA array.
                          - added DEBUG keyword
                          - eliminate obsolete XARR, YARR, ZARR keywords
                          - added NOPRINT keyword to suppress
                            call to CTM_PRINT_DATAINFO
        mgs, 02 Apr 1999: - replace gridinfo in fileinfo only if new
                            surface pressure is requested. Necessary 
                            for 2D fields (e.g. EPTOMS)
                          - deactivated SMALLCHEM flag
                          - added error checking for FILEINFO
        bmy, 28 Apr 1999: - return THISFILEINFO as a keyword
        mgs, 30 Jun 1999: - Specification of PSURF finally works.
        bmy, 13 Dec 1999: - now use CHKSTRU instead of N_ELEMENTS  
                            to diagnose undefined GRIDINFO structure
        bmy, 04 Dec 2000: GAMAP VERSION 1.47
                          - eliminated obsolete code from 12/31/99
        bmy, 03 Jun 2001: GAMAP VERSION 1.48
                          - bug fix: also create GRIDINFO structure
                            for grids with no vertical layers
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10

(See /n/home09/ryantosca/IDL/gamap2/gamap_util/ctm_get_datablock.pro)


CTM_GRID (FUNCTION)

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
        CTM_GRID  (function)

 PURPOSE:
        Set-up of the model grid for various models. While the
        horizontal grid information can be computed from a few
        basic parameters, the vertical structure is hardwired
        for each model seperately. Currently, the following models
        are supported: GEOS1, GEOS_STRAT, GEOS-3, GEOS-4, GEOS-5,
        GEOS-57, MERRA, GISS_II, GISS_II_PRIME, FSU, FVCCM, and MATCH.
       
 CATEGORY
        GAMAP Utilities, GAMAP Models & Grids, Structures

 CALLING SEQUENCE:
        RESULT = CTM_GRID( MTYPE [, Keywords ] )

 INPUTS:
        MTYPE --> a MODELINFO structure as returned from function 
             CTM_TYPE.  This structure  must contain the following tags: 
             resolution (a 2 element vector with DI, DJ), halfpolar, 
             center180, name, nlayers, ptop, psurf, hybrid.)
 
 OUTPUT:
        RESULT -> A structure, scalor, or vector variable depending 
             on the output keywords below.

 KEYWORD PARAMETERS:
        PSURF -> specify surface pressure in mb. Overrides 
            value passed in through modelinfo structure.

        The following keywords define output options. If none of these
        is set, a structure is returned that contains all parameters.
	   IMX     (int   ) -> Maximum I (longitude) dimension  [alt: NLON]
          JMX     (int   ) -> Maximum J (latitude ) dimension  [alt: NLAT]
          DI      (flt   ) -> Delta-I interval between grid box edges
          DJ      (flt   ) -> Delta-J interval between grid box edges
          YEDGE   (fltarr) -> Array of latitude  edges
          YMID    (fltarr) -> Array of latitude  centers
          XEDGE   (fltarr) -> Array of longitude edges   
          XMID    (fltarr) -> Array of longitude centers

          LMX     (int)    -> Maximum altitude level (layers)  [alt: NLAYERS]
          SIGMID  (fltarr) -> Array of sigma center values
          SIGEDGE (fltarr) -> Array of sigma edges
          ETAMID  (fltarr) -> Array of ETA center values
          ETAEDGE (fltarr) -> Array of ETA edge values
          PMID    (fltarr) -> Array of approx. pressure values for sigma ctrs
          PEDGE   (fltarr) -> ditto for sigma edges
          ZMID    (fltarr) -> Array of approx. mean altitudes for sigma ctrs
          ZEDGE   (fltarr) -> ditto. for sigma edges
          AP      (fltarr) -> Hybrid-grid "A" parameters
          BP      (fltarr) -> Hybrid-grid "B" parameters 

        /NO_VERTICAL --> do not return vertical grid info in structure
             In this case the MTYPE structure only needs to contain
             resolution, halfpolar and center180. This keyword is ignored if 
             a specific (vertical) output option is requested.

        DELTAZ_m --> For multi-level 'GENERIC' grids, DELTAZ_m specifies
             the height of each grid level in meters.  DELTAZ_m does not
             apply to any of the GEOS, GISS, etc. grid families.

 SUBROUTINES:
        External Subroutines Required:
        ===============================
        GETSIGMA   (function)
        GETETA     (function)
        USSA_ALT   (function)
        USSA_PRESS (function)
        ZMID       (function)

 REQUIREMENTS:
        Best if used with function CTM_TYPE.  Also requires functions
        GETSIGMA and GETETA for definition of vertical layers.

 NOTES:
        This routine is not very efficient in that it always computes 
        all the available information. But since it will not be
        called too often and does not handle large amounts of data, 
        we won't worry about computational efficiency here.

 EXAMPLE:
        MTYPE = CTM_TYPE( 'GEOS1' )
        MGRID = CTM_GRID( MTYPE )

        ; This will define the following structure (help,mgrid,/stru)

        ** Structure <10323808>, 17 tags, length=1624, refs=1:
           IMX             INT             72
           JMX             INT             46
           DI              FLOAT           5.00000
           DJ              FLOAT           4.00000
           XEDGE           FLOAT     Array[73]     (-177.500, -172.500, ...)
           YEDGE           FLOAT     Array[47]     (-90, -88, -84, ...)
           XMID            FLOAT     Array[72]     (-180.0, -175.0, ...)
           YMID            FLOAT     Array[46]     (-89, -86, -82, ...)
           LMX             INT             20
           SIGMID          FLOAT     Array[20]     (0.993936, 0.971301, ...)
           SIGEDGE         FLOAT     Array[21]     (1.00000,  0.987871, ...)
           ETAMID          FLOAT     Array[20]     (all zeroes)
           ETAEDGE         FLOAT     Array[21]     (all zeroes)
           PMID            FLOAT     Array[20]     (980.082, 957.990, ...)
           PEDGE           FLOAT     Array[21]     (986.000, 974.162, ...)
           ZEDGE           FLOAT     Array[21]
           ZMID            FLOAT     Array[20]
           AP              

        ; Or, with the use of output keywords:
             PRINT, CTM_GRID( CTM_TYPE( 'GISS_II' ), /PMID )

        ; IDL will print
             986.000      935.897      855.733      721.458      551.109 
             390.781      255.503      150.287      70.1236      10.0000

        ; A more awkward example (see yourself):
             HELP, CTM_GRID( { RESOLUTION : [3.6,3.0],           $
                               HALFPOLAR  : 0,                   $
                               CENTER180  : 0 }, /NO_VERT), /STRU

 MODIFICATION HISTORY:
        bmy, 19 Aug 1997: VERSION 1.00
        bmy, 24 Sep 1997: VERSION 1.01
        mgs, 26 Feb 1998: Version 2.00  - rewritten as a function
        mgs, 27 Feb 1998: - added vertical information
        mgs, 02 Mar 1998: - better defined interface with CTM_MODEL_TYPE
        bmy, 07 Apr 1998: - Renamed 
        mgs, 24 Apr 1998: - changed structure to named structure
        mgs, 04 May 1998: - changed back because of conflicting sizes
        mgs, 07 May 1998: - Renamed to CTM_GRID
                          - x coordinates now start with -182.5 for 
                            center180 grids
        bmy, 19 Jun 1998: - now uses USSA_ALT to compute altitudes
                            from pressure coordinates
                          - fixed some comments
                          - added FORWARD_FUNCTION statement
        mgs, 30 Jun 1999: - added PSURF keyword
        bmy, 27 Jul 1999: GAMAP VERSION 1.42
                          - now can compute pressure levels and
                            edges for hybrid sigma-pressure grids
                          - a few cosmetic changes
        bmy, 03 Jan 2000: - more cosmetic changes
        bmy, 20 Apr 2000: GAMAP VERSION 1.45
                          - now returns correct YMID values for FSU grid
        bmy, 15 Sep 2000: GAMAP VERSION 1.46
                          - fixed bug for computing YMID for grids
                            w/o halfpolar boxes.  This also fixes the
                            previous problem w/ the FSU grid.
        bmy, 03 Jul 2001: GAMAP VERSION 1.48
                          - If MTYPE.NLAYERS = 0, then create a
                            return structure w/o vertical level info
        bmy, 06 Nov 2001: GAMAP VERSION 1.49
                          - added ETAMID, ETAEDGE keywords
                          - added ETAMID, ETAEDGE tags to return structure
                          - now calls GETETA to return ETA coordinates
                            for hybrid models (such as GEOS-4/fvDAS)
                          - updated comments
        bmy, 18 Oct 2002: GAMAP VERSION 1.52
                          - deleted obsolete commented-out code
        bmy, 04 Nov 2003: GAMAP VERSION 2.01
                          - Use STRPOS to test for GEOS4 or 
                            GEOS4_30L model names
                          - Now treat GISS_II_PRIME 23-layer model
                            as a hybrid grid instead of using the
                            obsolete "fake" formulation.
        bmy, 28 Jun 2006: GAMAP VERSION 2.05
                          - bug fix for multi-level GENERIC grids
  bmy & phs, 16 Aug 2007: GAMAP VERSION 2.10
                          - now compute mXEDGE, mXMID, mYEDGE, mYMID
                            as double precision, and cast back to
                            float, so that we get correct values for
                            high-res grids like 0.5 x 0.666,
                          - cosmetic changes
                          - Special handling for GEOS-5 
                          - Now use USAGE, ROUTINE_NAME() instead of
                            function USE_CTM_GRID to display options
                          - Now return IMX, JMX as type LONG
        bmy, 03 Aug 2009: GAMAP VERSION 2.13
                          - Added DELTAZ_m to specify grid size in 
                            meters for multi-level GENERIC grids   
        bmy, 06 Aug 2010: GAMAP VERSION 2.14
                          - Added MERRA (identical to GEOS-5 grid, 
                            but retains MERRA name for clarity.)
        bmy, 28 Nov 2010: GAMAP VERSION 2.15
                          - Now use modified GETETA routine to
                            compute the pressure and ETA coords
                            consistently.
                          - Now save hybrid-grid parameters Ap and Bp 
                            to the GRIDINFO structure.
        bmy, 02 Feb 2012: GAMAP VERSION 2.16
                          - Add GEOS57 and GEOS57_47L grids, for
                            GEOS-5.7.x met data.  (These are
                            identical to the GEOS-5 and MERRA grids,
                            but we will denote them separately).
        bmy, 13 Aug 2015: GAMAP VERSION 2.19
                          - Add MERRA2 and MERRA2_47L grids

(See /n/home09/ryantosca/IDL/gamap2/gamap_util/ctm_grid.pro)


CTM_INDEX

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
        CTM_INDEX

 PURPOSE:
        Return index of CTM grid boxes for given coordinates
        (or vice versa) and allow user to interactively select
        a grid box

 CATEGORY:
        GAMAP Utilities, GAMAP Models & Grids

 CALLING SEQUENCE:
        CTM_INDEX,  [,i,j] [,keywords]

 INPUTS:
        MINFO --> Model type strucure as returned by CTM_TYPE.PRO
     or GINFO --> Model grid structure as returned by CTM_GRID.PRO
            If neither is given, the user will be prompted for a model 
            type and the grid will be computed.

        I, J --> index pair for which lon, lat coordinates shall
            be found if keyword /GET_COORDINATES is set. Also used 
            to return index values for given lon, lat pairs (this is 
            the default operation).  NOTE: I and J will be in "FORTRAN"  
            notation (e.g. the starting from 1 and not zero). To index
            IDL arrays, be sure to use I-1 and J-1. 

 KEYWORD PARAMETERS:
        CENTER --> a two element vector with (LAT, LON) coordinates
            for which the gridbox index shall be returned. Also used
            to return center coordinates for a given index pair if
            keyword /GET_COORDINATES is set.

        EDGE --> a four element vector in the MAP_SET LIMIT format
            (LAT0, LON0, LAT1, LON1). If keyword GET_COORDINATES is
            not set and no CENTER coordinates are given, I and J will 
            return two element vectors with I(0) corresponding to LON0 
            and I(1) corresponding to LON1 etc. In this case, it may
            be useful to retrieve WE_INDEX and SN_INDEX for indexing
            of CTM data arrays (note that these indices follow the IDL
            convention, i.e. starting from 0. To convert them into "true"
            CTM indices, add 1).
            If CENTER coordinates are provided or /GET_COORDINATES is set 
            then EDGE returns the grid box edges for the given or calculated 
            index pair.

        WE_INDEX --> integer array for indexing of CTM data arrays. This
            keyword is only used when EDGE is a valid 4 element vector,
            keyword GET_COORDINATES is not set and no coordinates are 
            passed in the CENTER keyword. This array is always arranged
            in west-east order (e.g. for EDGE=[0.,175.,0.,-175.] it will
            return [70, 71, 0] (GEOS1 grid)). 

        SN_INDEX --> like WE_INDEX but for latitude indexing. Note that
            latitude values in EDGE must be arranged in ascending order.

        /GET_COORDINATES --> return coordinates to given index rather
            than an index pair for given coordinates
        
        /NON_INTERACTIVE --> default action is interactive box picking per
            mouse (only need to supply MINFO in this case, but index and
            coordinates of last click will be returned in I, J, CENTER
            and EDGES repectively). Set this keyword if you want to convert
            values to and fro without drawing a map etc.

        XSIZE, YSIZE --> window size (default 900x600)

        MAPCENTER --> center coordinates for map projection [p0lat, polon ]

        COUNTRIES -> draw country boundaries

        _EXTRA --> keywords are passed to MAP_SET 
            (e.g. LIMIT=[lat0,lon0,lat1,lon1])
            Careful if you display data!

        WINDOW -> window number to plot into. Normally a new window
            is opened with the /free option. Use a specific window number
            to overlay the map onto existing data plotted with tvimage
             (see example).

        DATA -> a data array with dimensions matching your model grid
            (no error checking on this!) If DATA contains data, the value
            at the selected grid box, and a statistic for neighbouring 
            grid boxes will be displayed together with the corrdinates.

 OUTPUTS:
        Index of grid box in I, J, coordinates in named variables supplied
        with CENTER and EDGE keywords

 SUBROUTINES:

 REQUIREMENTS:
        needs CTM_TYPE for input of MINFO parameter and 
        CTM_DEFINE_GRID 

 NOTES:
        This routine makes substantial use of recursive calls. Be careful
        when changing.

 EXAMPLES:
        (1)
        CTM_INDEX, CTM_TYPE('GEOS1')

             ; Display world map and have fun. 

        (2)
        CTM_INDEX, CTM_TYPE( 'GEOS1',RESOLUTION=2 ), $
            I, J, LIMIT=[ 0.,-180., 90., -30. ]

             ; Display map of North America and select grid 
             ; boxes for GEOS 2x2.5 grid.
             ; Indices of last point are returned in I and J.

        (3)
        CTM_INDEX, CTM_TYPE('GISS_II_PRIME'),$
             I, J, CENTER=[ 42., -72.], /NON_INTERACTIVE
        print,I,J

             ; returns grid box index for Harvard Forest in 
             ; GISS CTM II' (21,33) without displaying a map

        (4)
        CTM_INDEX, CTM_TYPE('GISS_II'), $
             I, J, EDGE=[-25.,170.,0.,-100.], $
             WE_INDEX=WE, SN_INDEX=SN, /NON_INTERACTIVE

             ; returns [ 69, 70, 71, 0, 1, ... , 15 ] in WE and 
             ; [ 15, 16, ..., 21 ] in SN. I is [ 70, 16 ], and J 
             ; is [ 16, 22 ]. Note that I, J refer to CTM (= FORTRAN)
             ;  indices, whereas WS and SN are IDL array indices.
        
        (5) 
        IM    = BYTSCL( DATA,MAX=MAX(DATA))
        MINFO = CTM_TYPE( 'GENERIC', RES=[360./XDIM,180./YDIM] )
        GINFO = CTM_GRID(MINFO)
        TVIMAGE, IM, POSITION=P, /KEEP_ASPECT
        CTM_INDEX, GINFO, I, J, WINDOW=0, DATA=DATA

             ; Overlay interactive map onto data displayed with 
             ; TVIMAGE.  You should create a generic MODELINFO 
             ; structure in this case.  NOTE: replace xdim, ydim 
             ; with the dimensions of your data array!
             ; This example also demonstrates the use of ginfo vs. minfo.

 MODIFICATION HISTORY:
        mgs, 04 May 1998: VERSION 1.00
        mgs, 07 May 1998: - added MAPCENTER and _EXTRA keywords, 
                            fixed bug with lon index
                          - actually substantially rewritten
        mgs, 08 May 1998: VERSION 1.10
                          - CENTER and EDGE keywords now MAP_SET compatible
                          - added WE_INDEX and SN_INDEX keywords
                          - improved documentation
                          - bug fix for display of polar grid boxes
        mgs, 09 Jun 1998: - added COUNTRIES keyword
        mgs, 15 Jun 1998: - bug fix for WE
        mgs, 07 Oct 1998: - added interactive selection of model
        mgs, 22 Feb 1999: - added DATA, SHELLS and WINDOW keywords
        mgs, 23 Feb 1999: - can now use either minfo or ginfo as parameter
        bmy, 24 Jan 2001: GAMAP VERSION 1.47
                          - commented out annoying & useless warning msg
                          - updated comments
        bmy, 12 Mar 2003: GAMAP VERSION 2.02
                          - updated comments
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10
                          - now pass DEFAULTMODEL from @GAMAP_CMN
                            common block to SELECT_MODEL

(See /n/home09/ryantosca/IDL/gamap2/gamap_util/ctm_index.pro)


CTM_LABEL (FUNCTION)

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
        CTM_LABEL (function)

 PURPOSE:
        Returns strings for several CTM quantities.

 CATEGORY:
        GAMAP Utilities, GAMAP Plotting

 CALLING SEQUENCE:
        RESULT = CTM_LABEL( DATAINFO, MODELINFO [, Keywords ] )

 INPUTS:
        DATAINFO -> Structure returned from CTM_GET_DATA, which
             contains information about one data block
                      
        MODELINFO -> Structure returned from CTM_TYPE, which
             contains information about the particular model 


 KEYWORD PARAMETERS:
        AVERAGE -> Bit flag indicating the dimensions over which
                   to average the data:
                      1 :  longitudinal
                      2 :  latitudinal
                      4 :  vertical
             These values can be combined. E.g., to average over
             longitude and latitude use 3. A bit set in AVERAGE 
             supersedes the corresponding bit in  TOTAL (see below). 

        LAT -> Scalar value or array of latitudes used in the plot.
 
        LON -> Scalar value or array of longitudes used in the plot.
 
        LEV -> Scalar value or array of latitudes used in the plot.

        ALT -> Scalar value or array of altitudes used in the plot.

        PRS -> Scalar value or array of pressures used in the plot.

        TOTAL -> Bit flag indicating the dimensions over which
                 to sum the data:
                      1 :  longitudinal
                      2 :  latitudinal
                      4 :  vertical
             These values can be combined. E.g., to integrate over 
             longitude and latitude use 3. A bit set in AVERAGE 
             supersedes the corresponding bit in TOTAL (see above).


        FORMAT -> Specifies format for converting numeric values into
             string values, for selected fields (such as LAT and LON).
             Default is I14 (strings are trimmed).

        /NO_SPECIAL -> If set, will not place any special superscript
             or subscript characters into the strings returned in
             LABELSTRU.

 OUTPUTS:
        LABELSTRU -> Structure containing the following label fields:
             LAT:        String for latitude(s)     
             LON:        String for longitude(s)
             LEV:        String for vertical level(s)
             ALT:        String for altitude level(s)
             PRS:        String for pressure level(s)
             LATLON:     String that has format "(Lat,Lon)"
             TRACERNAME: String for the tracer name
             SCALE:      String for the tracer's scale factor
             UNIT:       String for the tracer's unit
             TAU0:       String representation of TAU0
             TAU1:       String representation of TAU1
             YMD0:       String representation of (YY)YYMMDD
                           corresponding to TAU0
             YMD1:       String representation of (YY)YYMMDD
                           corresponding to TAU1
             HMS0:       String representation of HHMMSS
                           corresponding to TAU0
             HMS1:       String representation of HHMMSS
                           corresponding to TAU1
             YEAR0:      String for the starting year (e.g. 1994)
             YEAR1:      String for the ending year 
             MONTH0:     String for the starting month name 
                          (e.g. "Jan", "Feb", "Mar", etc..)
             MONTH1:     String for the ending month name
             DAY0:       String for the starting day number (1-31)
             DAY1:       String for the ending day number (1-31)
             DATE:       String for the date (see below)
             MODEL:      String for the model name
             FAMILY      String for the model's family
             RES:        String for the resolution of the model 

 SUBROUTINES:
        External Subroutines Required:
        ==============================================
        CHKSTRU (function)     STRCHEM (function)
        STRSCI  (function)     TAU2YYMMDD (function)
   
 REQUIREMENTS:
        DATAINFO and MODELINFO must be passed to CTM_LABEL.  These
        structures are computed by the GAMAP package subroutines.

 NOTES:
        DATAINFO is created e.g. by CTM_GET_DATA (or CTM_GET_DATABLOCK)
        MODELINFO is created by CTM_TYPE

 EXAMPLE:
        CTM_LABEL, DataInfo, ModelInfo, LabelStru, Lat=10, Lon=48
       
        print, LabelStru.LAT
            'Lat=10!UN!N'       

 MODIFICATION HISTORY:
         bmy, 23 Sep 1998: VERSION 1.00
         bmy, 24 Sep 1998: - now ensure that RES is a scalar string
                           - place TAU2YYMMDD in FORWARD_FUNCTION call
         bmy, 28 Sep 1998: VERSION 1.01
                           - formats for LatStr, LonStr, LevStr
                             changed to be more consistent.
         mgs, 29 Sep 1998: - changed a few comments and fixed bug in 
                             MinLon/MaxLon
         bmy, 03 Nov 1998: - changed NAME to TRACERNAME for
                             the sake of consistency
         bmy, 12 Nov 1998: - added LABELSTRU structure tags: YEAR0,
                             YEAR1, MONTH0, MONTH1, DAY0, DAY1, and DATE
                           - now reports lats as S/N instead of -/+ 
                             and reports lons as W/E instead of -/+
         bmy, 17 Nov 1998: - now use function N_UNIQ to test for
                             the number of unique elements in
                             LAT, LON, LEV, ALT, PRS
                           - Added FORMAT keyword to specify 
                             format for LAT and LON strings
                           - updated comments
         bmy, 15 Jan 1999: - added NO_SPECIAL keyword
         bmy, 17 Feb 1999: - Now add GMT to date string for timeseries
                             animation plots (interval < 1 day)
                           - make sure that HMS0STR and HMS1STR have
                             string lengths of 6 characters
         bmy, 18 Feb 1999: - fix default DATE string for February
         mgs, 16 Mar 1999: - cosmetic changes
                           - removed SUBTRACT_ONE keyword and improved
                             choice of date format
         bmy, 13 Jul 2001: GAMAP VERSION 1.48
                           - Use updated version of STRREPL.PRO from mgs 
         bmy, 07 Nov 2001: GAMAP VERSION 1.49
                           - now use 8-digit YYYYMMDD format for
                             date variables YMD0, YMD1
         bmy, 02 Oct 2002: GAMAP VERSION 1.53
                           - now write GEOS3 instead of GEOS3_30L
         bmy, 05 Nov 2003: GAMAP VERSION 2.01
                           - now write GEOS4 instead of GEOS3_30L
                           - now use the proper time epoch for each
                             model family in call to TAU2YYMMDD
                           - updated comments
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10

(See /n/home09/ryantosca/IDL/gamap2/gamap_util/ctm_label.pro)


CTM_LOCATEDIFF

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 NAME:
        CTM_LOCATEDIFF

 PURPOSE:
        Locates data blocks which differ in two binary
        punch files or GMAO met field files.  

 CATEGORY:
        GAMAP Utilities, GAMAP Data Manipulation

 CALLING SEQUENCE:
        CTM_LOCATEDIFF, FILE1, FILE2 [, Keywords ]

 INPUTS:
        FILE1 -> Name of the first file to be tested.  FILE1 may be
             a binary punch file, and ASCII file, or a GMAO met field
             file.

        FILE2 -> Name of the second file to be tested.  FILE2 may be
             a binary punch file, and ASCII file, or a GMAO met field
             file.

 KEYWORD PARAMETERS:
        DIAGN -> A diagnostic category name to restrict the selection
             of data records.

        OUTFILENAME -> Name of the output file which will contain
             the location of differences found between data blocks
             in FILE1 and FILE2.  If OUTFILENAME is not specified,
             then CTM_LOCATEDIFF will print this information to
             the screen.

        /HEADERS_ONLY -> Set this switch to just print the category
             names and tracer numbers where differences occur instead
             of printing all of the data points.

        _EXTRA=e -> Picks up any extra keywords for CTM_GET_DATA.

 OUTPUTS:
        None

 SUBROUTINES:
        External subroutines required:
        ==============================
        CTM_GET_DATA   UNDEFINE
        CTM_DIAGINFO

 REQUIREMENTS:
        References routines from both GAMAP and TOOLS directories.

 NOTES:
        (1) Both FILE1 and FILE2 must contain the same diagnostic 
            categories, listed in the same order.

 EXAMPLE:
        CTM_LOCATEDIFF, 'ctm.bpch.old', 'ctm.bpch.new'

             ; Locates data blocks which differ between ctm.bpch.old
             ; and ctm.bpch.new.  You can investigate these further
             ; with routines CTM_PRINTDIFF and CTM_PLOTDIFF.

 MODIFICATION HISTORY:
        bmy, 24 Feb 2003: VERSION 1.00
        bmy, 19 Nov 2003: GAMAP VERSION 2.01
                          - Now get spacing between diagnostic
                            offsets from CTM_DIAGINFO
        bmy, 27 Feb 2004: GAMAP VERSION 2.02
                          - Rewritten to also print out locations in
                            FORTRAN notation where differences occur
                          - added DIAGN keyword to specify category name
                          - added OUTFILENAME to specify output file
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10
        bmy, 01 May 2013: GAMAP VERSION 2.17
                          - Corrected error in EXAMPLE section above

(See /n/home09/ryantosca/IDL/gamap2/gamap_util/ctm_locatediff.pro)


CTM_MAKE_DATAINFO (FUNCTION)

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
        CTM_MAKE_DATAINFO (function)

 PURPOSE:
        Create a datainfo and fileinfo structure from an
        "external" data set so that it can be used seamlessly
        within the GAMAP package. The dataset can have up to
        four dimensions (however, only the first 3 are currently
        supported). The new datainfo and fileinfo structures 
        will be added to the global structure arrays.

 CATEGORY:
        GAMAP Utilities, GAMAP Data Manipulation, Structures

 CALLING SEQUENCE:
        RESULT = CTM_MAKE_DATAINFO( DATA, DATAINFO, FILEINFO  [,Keywords] )

 INPUTS:
        DATA  -> A 1-D, 2-D, or 3-D data array.

 KEYWORD PARAMETERS:
        DIAGN -> A diagnostics name (category) or number that describes
               the data type. If not given, the user will be prompted.
               If DIAGN is a number that is not recognized as valid
               diagnostics by CTM_DIAGINFO, the number will be stored
               as string value. If DIAGN is a string, it does not have 
               to be a valid diagnostics category.

        DIM -> A 4 element vector with the DATA dimensions as
               LON, LAT, LEVEL, TIME. If not given, the dimensions
               of DATA will be entered sequentially. Use this keyword
               to properly identify e.g. a zonal mean data set as
               DIM = [ 0, 46, 20, 0 ] (for the GEOS-1).
               The order and magnitude of the dimensions in DIM must
               agree with the dimensions of the DATA array
               (e.g. if DATA(72,46) then DIM=[46,72,0,0] is not allowed).

        FILENAME-> Name of the file which is specified by the
               FILEINFO structure.  If FILENAME is not specified, 
               then the default FILENAME = "derived data".

        FILETYPE -> A numeric code to identify the file type.  If not
               specified then the default FILETYPE = -1.

        FIRSTBOX -> A 3 element vector containing IFIRST, JFIRST, and
               LFIRST, which are the starting indices for the LON,
               LAT, and LEVEL dimensions.  

        FORMAT -> A format string (for ASCII data) or descriptive
               string (for binary or self-describing data) that is
               saved to the DATAINFO structure.  Default is ''.

        GRIDINFO -> A gridinfo structure describing the grid set-up
               of the data set (see CTM_GRID). If not given, 
               CTM_MAKE_DATAINFO attempts to use the MODELINFO 
               structure to construct GRIDINFO.

        ILUN -> The file unit number that will be used to identify 
               FILEINFO and DATAINFO.  If not passed, then ILUN will
               be negative to denote derived data, and will increment
               negatively for each data block, starting at -1. 

        MODELINFO -> A modelinfo structure containing information
               about the model that generated the data (see CTM_TYPE).
               If not given, the user is prompted for a selection.

        /NO_GLOBAL -> If passed, will prevent the DATAINFO and FILEINFO
               structures from being appended to the global GAMAP
               common blocks.  Useful for saving memory.

        /NO_VERTICAL (passed via _EXTRA) -> set this keyword if you only want
               to create a 2D gridfinfo structure.

        TAU0, TAU1 -> Beginning and end of time interval that is spanned
               by DATA (as TAU value). Default is -1 for both.

        TOPTITLE -> A user defined string that may describe the data set
               in more detail.

        TRACER -> A tracer number or name that identifies the chemical 
               species or physical quantity contained in DATA. If 
               TRACER is an invalid name, it will be set to -1, and the
               string value of TRACER will be used as TRCNAME (see below). 
               If not given, the user will be prompted.

        TRCNAME -> A tracer name. Default is to use the name associated
               with that tracer number in CTM_TRACERINFO.

        SCALE -> A value that is entered in the SCALE field in DATAINFO.
               Default is 1.0.

        UNIT -> A unit string. Default is empty.

 OUTPUTS:
        DATAINFO, FILEINFO -> The datainfo and fileinfo structures
               generated from the "external" data array. These are 
               automatically appended to the global DATAINFO and FILEINFO 
               structures, unless the /NO_GLOBAL keyword is set.

 SUBROUTINES:
        External Subroutines Required:
        =========================================
        CREATE3DHSTRU, CREATE3DFSTRU, TAU2YYMMDD

 REQUIREMENTS:
        None

 NOTES:
        In the current version, no error checking is made whether the
        DATA dimensions agree with the grid information. This is the
        users responsibility. 

 EXAMPLES:
        (1)
        DATA   = DIST(72,46)
        RESULT = CTM_MAKE_DATAINFO( DATA, DATAINFO, FILEINFO )

             ; Create a 2D array and make a DATAINFO structure.
             ; The user will be prompted for model type, 
             ; diagnostics and tracer.
   
        (2)
        RESULT = CTM_MAKE_DATAINFO( DATA, DATAINFO, FILEINFO,        $
            MODEL=CTM_TYPE( 'GEOS1' ), DIAGN='IJ-AVG-$',             $ 
            TRACER=2, TAU0=NYMD2TAU(940901L), TAU1=NYMD2TAU(940930), $
            UNIT='PPBV', DIM=[0,46,20,0],                            $
            TOPTITLE='Zonal mean difference in Ox CLDS/no CLDS')

             ; Add a zonal mean difference data set (already in DATA) 

        (3)
        HELP, DATAINFO, /STRU
           ** Structure H3DSTRU, 13 tags, length=72:
              ILUN            LONG               -15
              FILEPOS         LONG                 0
              CATEGORY        STRING    'ZONE-AVG'
              TRACER          INT              2
              TRACERNAME      STRING    'Ox'
              TAU0            DOUBLE           84720.000
              TAU1            DOUBLE           85416.000
              SCALE           FLOAT           1.00000
              UNIT            STRING    'ppbv'
              FORMAT          STRING    ''
              STATUS          INT              1
              DIM             INT       Array[4]
              OFFSET          INT       Array[3]
              DATA            POINTER   

             ; Display DATAINFO structure

 MODIFICATION HISTORY:
        mgs, 09 Oct 1998: VERSION 1.00
        mgs, 19 Nov 1998: - bug fix. ILUN now always negative!
                          - unit now "required" parameter, i.e.
                            interactively asked for
        bmy, 11 Feb 1999: VERSION 1.01
                          - added OFFSET keyword so that I0, J0, and
                            L0 offsets can be stored in DATAINFO
                          - DATAINFO.TAU0 and DATAINFO.TAU1 are now
                            stored as double precision
                          - updated comments
        mgs, 16 Mar 1999: - cosmetic changes
                          - OFFSET changed into FIRSTBOX
        mgs, 30 Mar 1999: - added _EXTRA keyword for ctm_grid
                            (use for /NO_VERTICAL)
        bmy, 29 Jun 2001: GAMAP VERSION 1.48
                          - bug fix: now pass CTM_TRACERINFO the
                            tracer number plus diagnostic offset
        bmy, 06 Mar 2002: GAMAP VERSION 1.50
                          - now take TRACER mod 100L before 
                            adding the diagnostic offset to it
                            in call to CTM_TRACERINFO
        bmy, 26 Nov 2003: GAMAP VERSION 2.01
                          - added /NO_GLOBAL keyword
                          - rewrote for clarity; updated comments
                          - Now get diagnostic spacing from CTM_DIAGINFO
                          - added ILUN, FILENAME, FILETYPE keywords
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10
        phs, 30 May 2008: GAMAP VERSION 2.12
                          - Minor fix to restrict FIRSTBOX to 3 elements

(See /n/home09/ryantosca/IDL/gamap2/gamap_util/ctm_make_datainfo.pro)


CTM_MAPGRID

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
        CTM_MAPGRID

 PURPOSE:
        Plots CTM grid boxes superposed atop a world map.

 CATEGORY:
        GAMAP Utilities, GAMAP Models & Grids

 CALLING SEQUENCE:
        CTM_MAPGRID, GRIDINFO [, Keywords ]

 INPUTS:
        GRIDINFO -> Output structure returned from CTM_GRID
             containing information about the particular
             grid being used.

 KEYWORD PARAMETERS:
        COLOR -> Color index for the map outline, continents, and
             title.  Default is BLACK (assuming MYCT color table).

        G_COLOR -> Color index for the grid lines.  
             Default is BLACK (assuming MYCT color table).

        LIMIT -> Vector containing [ LatMin, LonMin, LatMax, LonMax ].
             These define the latitude and longitude ranges for
             the map projection.  If LIMIT is not supplied,
             CTM_MAPGRID will construct LIMIT from the information
             supplied in GRIDINFO.

        /PS -> If set, will send output to a PostScript file.

        _EXTRA=e -> Picks up any extra keywords for OPEN_DEVICE,
             MAP_SET, MAP_CONTINENTS, PLOTS, and CLOSE_DEVICE.

 OUTPUTS:
        None

 SUBROUTINES:
        External Subroutines Required:
        =========================================
        CHKSTRU       (function)   CONVERT_LON
        OPEN_DEVICE                CLOSE_DEVICE 
        MYCT_DEFAULTS (function)
        
 REQUIREMENTS:
        None

 NOTES:
        None

 EXAMPLES:
        (1)
        GRIDINFO = CTM_GRID( CTM_TYPE( 'GEOS1', RES=2 ) )
        CTM_MAPGRID, GRIDINFO, LIMIT=[ -90, 130, 90, -130 ], /ISOTROPIC

             ; Plots a world map (pacific region, spanning
             ; the date line) for the GEOS-1 2 x 2.5 grid 


        (2)
        CTM_MAPGRID, GRIDINFO, LIMIT=[ -90, -182.5, 90, 177.5 ], /ISOTROPIC

             ; For the same grid as above, plots the entire world
             ; centered on 0 degrees lat and 0 degrees longitude.

 MODIFICATION HISTORY:
        bmy, 03 Nov 1999: VERSION 1.00
        bmy, 24 Mar 2000: VERSION 1.45
                          - now prints map labels 
                          - added /NOBORDER to MAP_SET call
        bmy, 27 May 2003: GAMAP VERSION 1.53
                          - now plots continent lines after grid lines
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10

(See /n/home09/ryantosca/IDL/gamap2/gamap_util/ctm_mapgrid.pro)


CTM_MASS_CHECK

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
        CTM_MASS_CHECK

 PURPOSE:
        Plots the time evolution of % difference of tracer mass and 
        air mass from a CTM simulation.  Used to assess mass
        conservation in CTM transport codes.

 CATEGORY:
        GAMAP Utilities, GAMAP Data Manipulation

 CALLING SEQUENCE:
        CTM_MASS_CHECK [, Keywords ]

 INPUTS:
        FILENAME -> Name of the CTM output file containing air mass
             and tracer concentrations.  FILENAME can be either an
             ASCII punch file or a BINARY punch file.  If omitted,
             the user will be prompted to supply FILENAME via a 
             dialog box.

 KEYWORD PARAMETERS:
        TRACER -> Number of the tracer that you wish to check for
             mass conservation.

        /PS -> Set this switch to create PostScript plot output.

        OUTFILENAME -> If /PS is set, OUTFILENAME will be the name of
             the PostScript plot output file.  Default is "mass_check.ps".

        _EXTRA=e -> Catches extra keywords for routines OPEN_DEVICE
             and CLOSE_DEVICE.

 OUTPUTS:
        None

 SUBROUTINES:
        External Subroutines Required:
        ===============================
        CLOSE_DEVICE   CTM_GET_DATA
        MULTIPANEL     OPEN_DEVICE    
        UNDEFINE

 REQUIREMENTS:
        References routines from both GAMAP and TOOLS packages.

 NOTES:
        (1) Assumes that the tracer concentration has been saved
            under the IJ-AVG-$ diagnostic category.  Also assumes 
            that the airmass has been saved under the BXHGHT-$
            diagnostic category.  

 EXAMPLE:
        CTM_MASS_CHECK, 'ctm.bpch.geos4', TRACER=4

            ; Plots the evolution of % difference of both
            ; tracer and air mass for CO from a GEOS-4 simulation.

 MODIFICATION HISTORY:
  bdf & bmy, 26 Jun 2003: GAMAP VERSION 2.03
        bmy, 06 Mar 2007: GAMAP VERSION 2.06
                          - make FILENAME an input rather than
                            a keyword argument.
                          - now pass _EXTRA=e to the PLOT command
                          - Added WINPARAM keyword
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10

(See /n/home09/ryantosca/IDL/gamap2/gamap_util/ctm_mass_check.pro)


CTM_NAMEXT

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
        CTM_NAMEXT

 PURPOSE:
        Returns the proper filename extension for CTM model names.

 CATEGORY:
        GAMAP Utilities, GAMAP Models & Grids

 CALLING SEQUENCE:
        RESULT = CTM_NAMEXT( MODELINFO )

 INPUTS:
        MODELINFO -> a MODELINFO structure (output from function
             CTM_TYPE) desribing the desired CTM model.

 KEYWORD PARAMETERS:
        None

 OUTPUTS:
        RESULT -> Returns a string containing the model name 
             (e.g. 'geos3', 'geos4', 'geos5', 'gcap', 'giss2p', 
              'generic', etc.).

 SUBROUTINES:
        External Subroutines Required:
        ==============================
        CHKSTRU (function)

 REQUIREMENTS:
        None

 NOTES:
        (1) Add more model names as is necessary.

 EXAMPLE:
        MODELINFO = CTM_TYPE( 'GEOS_STRAT', RESOLUTION=4 )
        PRINT, CTM_NAMEXT( MODELINFO )
             geoss

             ; Returns filename extension for the GEOS-STRAT model

 MODIFICATION HISTORY:
        bmy, 30 Jun 2000: GAMAP VERSION 1.46
        bmy, 02 Jul 2001: GAMAP VERSION 1.48
                          - added GENERIC as a return option
        bmy, 02 Oct 2003: GAMAP VERSION 1.53
                          - now add GEOS3_30L to the CASE statement
        bmy, 16 Oct 2003: - now add GEOS4 to the CASE statement
        bmy, 12 Feb 2004: GAMAP VERSION 2.01a
                          - added GEOS4_30L to the CASE statement
        bmy, 05 Aug 2004: GAMAP VERSION 2.02
                          - added GCAP to the CASE statement
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10
                          - added GEOS5, GEOS5_47L to the CASE statement
        bmy, 04 Jan 2010: GAMAP VERSION 2.15
                          - added MERRA, MERRA_47L to the CASE statement
        bmy, 09 Feb 2012: GAMAP VERSION 2.16
                          - added GEOS57, GEOS57_47L to the CASE statement
        mps, 06 Nov 2013: - added GEOSFP, GEOSFP_47L to the CASE statement
        mps, 28 Oct 2015: - added MERRA2, MERRA2_47L to the CASE statement

(See /n/home09/ryantosca/IDL/gamap2/gamap_util/ctm_namext.pro)


CTM_NOYBUDGET

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
        CTM_NOYBUDGET

 PURPOSE:
        Computes the NOy budget within a given 3-D region.

 CATEGORY:
        GAMAP Utilities, GAMAP Data Manipulation

 CALLING SEQUENCE:
        CTM_NOYBUDGET [, BATCHFILE [, Keywords ] ]

 INPUTS:
        BATCHFILE (optional) -> Name of the batch file which 
             contains inputs that defines the 3-D region and NOy
             constituents.  If BATCHFILE is omitted, then the user
             will be prompted to supply a file name via a dialog box.

 KEYWORD PARAMETERS:
        LOGFILENAME (optional) -> Name of the log file where output 
             will be sent.  Default is "noy_budget.log".

 OUTPUTS:
        None

 SUBROUTINES:
        Internal Subroutines:
        --------------------------------------------------------------
        ErrorNOy                       (function)
        TruncateAndWrapForNOy          (function)
        GetNoxEmissionsForNOy          (function)  
        GetHNO3WetDepForNOy            (function)
        GetDryDepositionForNOy         (function)  
        GetNetExportForNOy             (function)
        GetNetChemicalProductionForNOy (function)  
        ReadBatchFileForNOy            (procedure)

        External Subroutines:
        --------------------------------------------------------------
        CTM_Get_Datablock (function)  CTM_BoxSize (function)

 REQUIREMENTS:
        None

 NOTES:
        (1) CTM_NOYBUDGET was developed for use with the GEOS-CTM,
            there might be some adaptation required for use with
            other models.

        (2) Only 5 "families" are considered: 
            Dry Deposition, NOx, PAN, HNO3, R4N2.

        (3) Wrapping around the date line seems to work but you
            should always double-check.

 EXAMPLE:
        CTM_NOYBUDGET, 'box1.dat', LogFileName='box1.log'
           
             ; Computes NOy budgets for the region specified in
             ; the file "box1.dat" and sends output to the 
             ; "box1.log" log file.

 MODIFICATION HISTORY:
        bmy, 28 Jan 2000: VERSION 1.00
                          - adapted original code from Isabelle Bey
        bmy, 25 May 2000: VERSION 1.45
                          - now allow the user to specify diagnostic
                            category names in the batch file
                          - added internal function "TruncateAndWrapForNOy"
                            to wrap arrays around the date line
                          - added internal procedure "ErrorNOy"
                            to do error checking for CTM_GET_DATABLOCK
                          - now can create budgets for more than one
                            diagnostic interval
                          - now allow user not to compute chemical 
                            production data for given families
        acs, 26 May 2000: - bug fixes: now do not stop the run if 
                            data blocks are not found
        bmy, 01 Aug 2000: VERSION 1.46
                          - use abs( Total( X ) ) > 0 when testing if 
                            transport fluxes are all nonzero
        bmy, 24 Jan 2001: GAMAP VERSION 1.47
                          - now no longer require all types of emissions
                            to be nonzero in order to sum them
                          - now no longer require both HNO3 LS and
                            convective wetdep to be zero in order to 
                            sum them
        bmy, 17 Jan 2002: GAMAP VERSION 1.50
                          - now call STRBREAK wrapper routine from
                            the TOOLS subdirectory for backwards
                            compatiblity for string-splitting
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10

(See /n/home09/ryantosca/IDL/gamap2/gamap_util/ctm_noybudget.pro)


CTM_OPEN_FILE

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
        CTM_OPEN_FILE

 PURPOSE:
        Open a CTM output (punch) file and reads the complete
        header information from that file. The file may be either
        ASCII or binary type, and is only opened if not already 
        parsed. It is re-opened if it was parsed but closed in the 
        meantime. CTM_OPEN_FILE can also be used to read GEOS-CTM
        restart files. However, since it is not possible to
        point randomly at these data, the complete set of tracers
        in a restart file will be read at once.
        
        While in general files are opened automatically when 
        CTM_GET_DATA is used, there are several circumstances where
        direct use of CTM_OPEN_FILE advantageous:
        * if a read error occurs, use CTM_OPEN_FILE with the /PRINT
          keyword to diagnose the error
        * to compare two model runs, it is simpler to first open
          the two files, then call CTM_GET_DATA without the filename
          keyword. All operations will then be done on both files
          in parallel.

 CATEGORY:
        GAMAP Internals

 CALLING SEQUENCE:
        CTM_OPEN_FILE, FILENAME, THISFILEINFO, THISDATAINFO

 INPUTS:
        FILENAME -> The name of the file to be opened or a
            file mask. If the file was not found or the file 
            mask contains wild cards, a pickfile dialog is
            opened for interactive selection. The default
            search mask can be set in gamap.defaults (see
            GAMAP_INIT).

 KEYWORD PARAMETERS:
        CANCELLED -> Returns 1 if the CANCEL button was pressed
            during DIALOG PICKFILE filename selection.
 
        _EXTRA keywords are passed to the various routines which
            read the file headers.  

 OUTPUTS:
        THISFILEINFO -> A named variable that will contain a 
            fileinfo structure (see CREATE3DFSTRU).

        THISDATAINFO -> A named variable that will contain an
            array of datainfo structures (see CREATE3DHSTRU)
            associated with this file.

        THISFILEINFO and THISDATAINFO are also appended to the 
        global pointer variables pGlobalFileInfo and pGlobalDataInfo
        (see gamap_cmn.pro and GAMAP_INIT).

 SUBROUTINES:
        Internal Subroutines:
        ============================================================
        Get_Free_Lun  (function)   Test_For_NCDF          (function)
        Test_For_HDF  (function)   Test_For_HDFEOS        (function)
        Test_For_GMAO (function)   Test_For_Binary        (function)
        File_Parse    (function)   File_Opened_Previously (function)
        Handle_Prev_Opened_File

        External Subroutines Required:
        ==============================================================
        GAMAP_CMN          (incl file)  OPEN_FILE
        CTM_READ3DB_HEADER (function )  CTM_READ3DB_HEADER (function)
        CTM_READ_GMAO      (function )  CTM_READ_NCDF      (function) 
        CTM_READ_GMI       (function )  LITTLE_ENDIAN      (function)
        STRRIGHT           (function )

 REQUIREMENTS:
        References routines from both GAMAP and TOOLS packages.

 NOTES:
        (1) In internal function "test_for_dao", add additional met 
        field names as is necessary to the FIELDNAMES array.  The
        first met field name in a file is tested against FIELDNAMES.
        If there is a match, then the file is declared to be a DAO 
        met field file, and it is assigned a file type of 4.

        (2) You must also add additional met field names to routine
        "ctm_read_dao" as is necessary.  The DAO met field files do 
        not carry tracer numbers, so the name of each met field must
        be checked in "ctm_read_dao" before a corresponding DATAINFO
        structure can be assigned.

        (3) If a binary file is the wrong endian, we will get a
        "Corrupted F77 file error" when we try to read data from it.
        We now test for this error in routines TEST_FOR_BINARY and
        TEST_FOR_DAO.  If this error condition occurs, the file is
        re-opened with the /SWAP_ENDIAN command.

 EXAMPLE:
        CTM_OPEN_FILE
        ; queries the user for a filename and stores the analyzed
        ; header information in the global common block
        ; If an ASCII punch file is read, the user is prompted for
        ; a model name

        CTM_OPEN_FILE,'',fileinfo,datainfo
        ; opens a CTM punch file after selection from a pickfile
        ; dialog

        CTM_OPEN_FILE,'~/amalthea/CTM4/run/ctm.pch',fileinfo,datainfo
        ; opens the specified punch file

 MODIFICATION HISTORY:
        mgs, 14 Aug 1998: VERSION 1.00
        mgs, 17 Sep 1998: - file units now starting from 20, so
                            they do not interfere with GET_LUN
        mgs, 21 Sep 1998: - changed gamap.cmn to gamap_cmn.pro
        mgs, 05 Oct 1998: - added function file_parse
                          - can now handle GEOS restart files as well.
        mgs, 10 Nov 1998: - no message after Cancel on Pickfile dialog
        bmy, 20 Jan 1999: - explicitly set binary type to 2 for 
                            GEOS-CTM restart files
                          - accept bey's personal GEOS CTM timeseries label
        mgs, 19 May 1999: - added SWAP_ENDIAN keyword to open_file if
                            binary files are read on PC
        mgs, 24 May 1999: - added support for 'CTM bin 02' files
                            (involved changing filetype numbers)
        bmy, 12 Apr 2000: GAMAP VERSION 1.45
                          - added test for DAO binary met field files
        bmy, 12 Jun 2000: - added CLDFRC to list of recognized DAO fields
        bmy, 28 Jul 2000: GAMAP VERSION 1.46
                          - added GEOS-3 names to list of recognized fields
                          - deleted a couple of field names woe don't use
        bmy, 25 Sep 2000: - added new field: SLP (sea level pressure)
        bmy, 05 Dec 2000: GAMAP VERSION 1.47
                          - added new fields: TKE, RH, KH
        bmy, 07 Mar 2001: - added new fields: CLDTMP, TPW
        bmy, 25 Apr 2001: - added new fields: TAULOW, TAUMID, TAUHI
        bmy, 26 Jul 2001: GAMAP VERSION 1.48
                          - added new field: T2M
        bmy, 15 Aug 2001: - added new field: OPTDEPTH
        bmy, 27 Sep 2001: GAMAP VERSION 1.49
                          - reference LITTLE_ENDIAN in internal
                            subroutine "handle_prev_opened_file"
                          - swap endian if LITTLE_ENDIAN() returns true
                            in internal subroutine "handle_prev_opened_file"
        bmy, 29 Jan 2002: GAMAP VERSION 1.50
                          - added new field: GWET
        bmy, 03 Mar 2003: GAMAP VERSION 1.52:
                          - added new fvDAS fields: CMFDTR, CMFETR,
                            ZMDU, ZMED, ZMEU, ZMMD, ZMMU, HKETA, HKBETA
        bmy, 18 Jun 2003: GAMAP VERSION 1.53
                          - added new fields: EVAP, LAI, PARDF, PARDR
        bmy, 30 Jul 2003: - added new field: TSKIN
  lyj & tdf, 22 Oct 2003: - added SWAP_BINARY keyword to TEST_FOR_BINARY
                          - Call TEST_FOR_BINARY with /SWAP_BINARY
                            as a last-ditch effort if the file type
                            cannot be classified.  This will open the
                            file and swap the endian.
        bmy, 12 Dec 2003: GAMAP VERSION 2.01
                          - Now also test for netCDF file format
                          - Added internal routines TEST_FOR_NETCDF,
                            TEST_FOR_HDF (stub), TEST_FOR_HDFEOS
                          - FILETYPE for ASCII   files range from 0-99
                          - FILETYPE for BINARY  files range from 100-199
                          - FILETYPE for netCDF  files range from 200-299
                          - FILETYPE for HDF-EOS files range from 300-399
                          - Routine TEST_FOR_GMAO now looks for met
                            field tracer names from "tracerinfo.dat",
                            instead of using a hardwired string array
                          - rewritten for clarity; updated comments
                          - Now looks for the GEOS-4 met field ident string
        bmy, 11 Feb 2004: GAMAP VERSION 2.01a
                          - Now prevents infinite loops when testing
                            for file type
        bmy, 24 Aug 2004: GAMAP VERSION 2.03
                          - now recognizes GEOS-CHEM station timeseries
                            file in bpch file format by the FTI string
        bmy, 21 Mar 2005: - Added COARDS-compliant netCDF as FILETYPE=203
        bmy, 24 May 2005: GAMAP VERSION 2.04
                          - Now test properly for GCAP met fields
        bmy, 06 Feb 2006: - Activate file type tests for HDF-EOS4 
                            swath and point file types
                          - Add new function TEST_FOR_HDF5 to test if
                            the file is in HDF5 format
                          - Use the absolute path name internally when
                            testing for HDF5 or HDF-EOS files
        bmy, 31 May 2006: GAMAP VERSION 2.05
                          - Now expand the filename when calling NCDF_OPEN
                          - Skip test for HDF5 for IDL versions
                            earlier than 6.0
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10
                          - Now modified for GEOS-5
                          - Added FILETYPE=106 for files that
                            contain 4-D data blocks
                          - Use FILETYPE=202 for netCDF files
                            created by BPCH2GMI
        phs, 30 Jun 2008: GAMAP VERSION 2.12
                          - warning if too many files are opened
                          - completly rewrite handling of endian swapping
        bmy, 23 Jan 2017: GAMAP VERSION 2.19
                          - Add a better test for netCDF files.  This
                            removes the restriction of the file having
                            to end with *.nc or *.nc4.
               

(See /n/home09/ryantosca/IDL/gamap2/internals/ctm_open_file.pro)


CTM_OVERLAY

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
        CTM_OVERLAY

 PURPOSE:
        Calls TVMAP to plot a pixel or contour map and then overplots 
        either an aircraft flight track or individual station data 
        atop it.

 CATEGORY:
        GAMAP Utilities, GAMAP Plotting

 CALLING SEQUENCE:
        CTM_OVERLAY, DATA,   XMID,   YMID, $
                     TRACKD, TRACKX, TRACKY [, Keywords ]

 INPUTS:
        DATA -> Data array (e.g. from CTM_GET_DATA or CTM_GET_DATABLOCK)
             from which a pixel plot or contour plot will be generated.

        XMID -> Vector of longitudes corresponding to DATA.

        YMID -> Vector of latitudes corresponding to DATA

        TRACKD -> Vector of data values corresponding to the aircraft
             flight track or station data points.

        TRACKX -> Vector of longitudes corresponding to the aircraft 
             flight track or station data points.  Should be in the 
             range [-180,180].

        TRACKY -> Vector of longitudes corresponding to the aircraft
             flight track or station data points.  Should be in the 
             range [-90,90].

 KEYWORD PARAMETERS:
        C_COLORS -> Vector to specify the color levels for filled
             contour plots.  If not passed, then C_COLORS will return
             to the calling program the default color level values
             generated internally by TVMAP.
 
        C_LEVELS -> Vector containing contour levels for filled
             contour plots.  Used in conjunction with /FCONTOUR. 

        COLOR -> Color of the map outline.  Passed to TVMAP.

        /FCONTOUR -> Set this switch to generate a filled-contour
             plot instead of a pixel plot.

        /LOG -> Set this switch to use a logarithmic color table.

        MINDATA -> Minimum value of DATA.  If omitted, then MINDATA
             will be automatically set to the minimum value of DATA.

        MAXDATA -> Minimum value of DATA.  If omitted, then MINDATA
             will be automatically set to the minimum value of DATA.

        /OVERPLOT -> Set this keyword to overplot a flight track
             atop a map previously drawn by TVMAP.

        T_COLOR -> (1) If plotting aircraft flight track data, then
             T_COLOR will be used to define the color of the line.
             (2) If plotting symbol data, then T_COLOR will be used to
             describe the color of the border around the symbol.  
             To suppress printing a border around the symbol, use
             any negative value for T_COLOR (e.g. T_COLOR = -1).

        T_LINESTYLE -> IDL linestyle for the aircraft flight track.
             Takes same values as the LINESTYLE graphic keyword
             (see help pages).

        T_SYMBOL -> Argument to the SYM keyword, which will be used
             to define the individual data points if you are plotting
             station data.  Recommended value: 1 (filled circle).

        T_THICK -> Thickness of the aircraft flight track, in pixels.
 
        _EXTRA=e -> Passes extra keywords to TVMAP and OPLOT.

 OUTPUTS:
        None

 SUBROUTINES:
        Internal Subroutines:
        ==========================================
        SCALETRACK (function)

        External Subroutines Required:
        =========================================
        MULTIPANEL      MYCT_DEFAULTS (function) 
        TVMAP           RECTANGLE
        SYM (function)

 REQUIREMENTS:
        None

 NOTES:
        You can pass all of the same keywords to CTM_OVERLAY_FLIGHT
        as you do to TVMAP.    

 EXAMPLE:
        (1) Plot flight tracks atop a pixel or contour map
        --------------------------------------------------

        ; Read the data -- in this case, CO concentrations
        SUCCESS = CTM_Get_DataBlock( Data, 'IJ-AVG-$',     $
                                     File='ctm.bpch.1995', $
                                     Tra=4,                $
                                     /First,               $
                                     Lon=[-180, 180],      $
                                     Lat=[-88,   88],      $
                                     Lev=1,                $
                                     XMid=XXmid, Ymid=YYMid )
         
        
        ; Make a "fake" aircraft track
        ; Here we'll use MAP_2POINTS to create a "fake" flight 
        ; track of constant longitude (30 deg E meridian)
        nPts   = 101
        a      = MAP_2POINTS( 30, -90, 30, 90, NPATH=NPTS )
        TrackX = A[0,*]
        TrackY = A[1,*]
        TrackD = FltArr( nPts )                  
               
        ; Plot a pixel map w/ countries, continents, grid lines,
        ; and overlay a red, dashed-line flight track atop it.
        CTM_OverLay, Data, XXMid, YYMid, TrackD, TrackX, TrackY, $
           /Sample,    /Countries,    /Coasts,    /CBar,         $      
           Div=4,      Min_Val=1e-20, /Isotropic, /Grid,         $ 
           Title='Pixel map overlaid /w contour map',            $    
           T_Color=!MYCT.RED, T_Thick=2, T_LineStyle=2
         
        ; Make a second "fake" aircraft track
        ; (of course, if you have a real flight track, use it...)
        TrackX = Replicate( 72, 100 )
        TrackY = Findgen( 100 ) - 50
        TrackD = Fltarr( 100 )
         
        ; Call CTM_OVERLAY again with /OVERPLOT to 
        ; overplot the second flight track
        CTM_OverLay, Data, XXMid, YYMid, TrackD, TrackX, TrackY, $
           T_Color=!MYCT.BLUE, T_Thick=2, T_LineStyle=2, /OVERPLOT


       (2) Draw Boxes for Tagged Tracer regions
       ----------------------------------------

       ; Define (X,Y) coordinates of first tagged tracer region
       TrackX = [ 0, 60, 60,  0, 0 ]
       TrackY = [ 0,  0, 30, 30, 0 ]
       TrackD = [ 0,  0,  0,  0, 0 ]
    
       ; Call CTM_OVERLAY with all TVMAP keywords to
       ; plot the map and to initialize the map dataspace
       CTM_OverLay, Data, XXMid, YYMid, TrackD, TrackX, TrackY, $
          /Sample,    /Countries,    /Coasts,    /CBar,         $      
          Div=4,      Min_Val=1e-20, /Isotropic, /Grid,         $       
          Title='Test pixel map w/ overlay boxes',              $
          T_Thick=3,  T_Color=!MYCT.BLACK,  T_LineStyle=0
    
       ; Define second tagged tracer region
       TrackX = [ 0, 120, 120,   0, 0 ]
       TrackY = [ 0,   0, -30, -30, 0 ]
          
       ; Call CTM_OVERLAY with /OVERPLOT to overplot
       ; atop the previously defined map
       CTM_OverLay, Data, XXMid, YYMid, TrackX, TrackY, $
          /OVERPLOT, T_Thick=3, T_Color=!MYCT.RED, T_LineStyle=0


       (3) Plot individual station data points
       ----------------------------------------

       ; Define "fake" station data for demo
       ; (along the equator between 60W and 60E)
       Ind    = Where( XMid ge -60 AND XMid le 60, N )
       TrackD = Findgen(N) + 20
       TrackY = Fltarr(N)  + 0
       TrackX = Xmid[Ind]

       ; Call CTM_OVERLAY with all TVMAP keywords to
       ; plot the map and to initialize the map dataspace
       CTM_OverLay, Data, XXMid, YYMid, TrackD, TrackX, TrackY, $
          /Sample,    /Countries,    /Coasts,    /CBar,         $      
          Div=4,      Min_Val=1e-20, /Isotropic, /Grid,         $      
          T_Symbol=1, SymSize=2,                                $
          Title='Test pixel map w/ station data',           
         

 MODIFICATION HISTORY:
        bmy, 05 Oct 2006: GAMAP VERSION 2.05
                          - Modified from CTM_OVERLAY_FLIGHT and
                            renamed to CTM_OVERLAY
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10
  dbm & bmy, 06 Nov 2007: - Modified to allow filled contour plots
  cdh & bmy, 18 Feb 2009: GAMAP VERSION 2.13
                          - Now pass LOG=LOG to TVMAP call to ensure
                            that TVMAP gets the /LOG keyword OK
  bmy & cph, 14 Jan 2010: GAMAP VERSION 2.14
                          - Remove the call to the PLOT command after
                            TVMAP. This does set up the approropriate
                            coordinates for map projections other
                            than /CYLINDRICAL.
                          - Now use PLOTS to plot symbols or lines
                            rather than OPLOT.
                          - Updated comments
        cdh, 24 Feb 2010: - Added /NOADVANCE keyword
        bmy, 06 Aug 2010: GAMAP VERSION 2.14
                          - Now set default values for C_COLORS
                            for filled contour plots if not specified
   bf & bmy, 18 Oct 2010: - Bug fix submitted by Bonne Ford to allow
                            more than one overlay on the same plot
        bmy, 10 Feb 2016: GAMAP VERSION 2.19
                          - If plotting symbols, suppress symbol borders
                            if T_COLOR is negative (e.g. T_COLOR=-1).
                          - Now require adding /NOADVANCE before each 
                            successive call to CTM_OVERLAY with /OVERPLOT

(See /n/home09/ryantosca/IDL/gamap2/gamap_util/ctm_overlay.pro)


CTM_OVERLAY_WIND

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
        CTM_OVERLAY_WIND

 PURPOSE:
        Calls TVMAP to plot a pixel or contour map and then overplots 
        wind data atop it.
        %%%% NOTE: Still in BETA testing! %%%%

 CATEGORY:
        GAMAP Utilities, GAMAP Plotting

 CALLING SEQUENCE:
        CTM_OVERLAY, DATA, XMID, YMID, U, V, [, Keywords ]

 INPUTS:
        DATA -> Data array (e.g. from CTM_GET_DATA or CTM_GET_DATABLOCK)
             from which a pixel plot or contour plot will be generated.

        XMID -> Vector of longitudes corresponding to DATA.

        YMID -> Vector of latitudes corresponding to DATA

        U -> Array of U-wind values

        V -> Array of V-wind values

 KEYWORD PARAMETERS:
        COLOR -> Color of the map outline.  Passed to TVMAP.

        /LOG -> Set this switch to use a logarithmic color table.

        MINDATA -> Minimum value of DATA.  If omitted, then MINDATA
             will be automatically set to the minimum value of DATA.

        MAXDATA -> Minimum value of DATA.  If omitted, then MINDATA
             will be automatically set to the minimum value of DATA.

        /OVERPLOT -> Set this keyword to overplot the wind
             atop a map previously drawn by TVMAP.
 
        _EXTRA=e -> Passes extra keywords to TVMAP and VELOCITY_FIELD.

 OUTPUTS:
        None

 SUBROUTINES:
        Internal Subroutines:
        ==========================================
        SCALETRACK (function)

        External Subroutines Required
        =========================================
        MULTIPANEL      MYCT_DEFAULTS (function) 
        TVMAP           RECTANGLE
        SYM (function)

 REQUIREMENTS:
        Uses routines from both GAMAP and TOOLS packages.

 NOTES:
        You can pass all of the same keywords to CTM_OVERLAY_FLIGHT
        as you do to TVMAP.    

 EXAMPLE:
        (1) Plot flight tracks atop a pixel or contour map
        --------------------------------------------------

        ; Read the data -- in this case, CO concentrations
        SUCCESS = CTM_Get_DataBlock( Data, 'IJ-AVG-$',     $
                                     File='ctm.bpch.1995', $
                                     Tra=4,                $
                                     /First,               $
                                     Lon=[-180, 180],      $
                                     Lat=[-88,   88],      $
                                     Lev=1,                $
                                     XMid=XXmid, Ymid=YYMid )
         

        ; Make a "fake" wind [TO DOCUMENT]
         

 MODIFICATION HISTORY:
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10
        phs, 20 Mar 2008: GAMAP VERSION 2.12
                          - cleanup, updated for new TVMAP
                          - now pass Map Position to velocity_field

(See /n/home09/ryantosca/IDL/gamap2/gamap_util/ctm_overlay_wind.pro)


CTM_OXBUDGET

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
        CTM_OXBUDGET

 PURPOSE:
        Computes the Ox budget within a given 3-D region.

 CATEGORY:
        GAMAP Utilities, GAMAP Data Manipulation

 CALLING SEQUENCE:
        CTM_OXBUDGET [, BATCHFILE [, Keywords ] ]

 INPUTS:
        BATCHFILE (optional) -> Name of the batch file which 
             contains inputs that defines the 3-D region and NOy
             constituents.  If BATCHFILE is omitted, then the user
             will be prompted to supply a file name via a dialog box.

 KEYWORD PARAMETERS:
        LOGFILENAME (optional) -> Name of the log file where output 
             will be sent.  Default is "ox_budget.log".

 OUTPUTS:
        None

 SUBROUTINES:
        Internal Subroutines:
        --------------------------------------------------------------
        ErrorOx                       (function)
        TruncateAndWrapForOx          (function)
        GetHNO3WetDepForOx            (function)             
        GetDryDepositionForOx         (function)  
        GetNetChemicalProductionForOx (function)  
        GetNetExportForOx             (function)
        ReadBatchFileForOx            (procedure)

        External Subroutines Required:
        --------------------------------------------------------------
        CTM_Get_Datablock (function)  CTM_BoxSize (function)

 REQUIREMENTS:
 

 NOTES:
        (1) CTM_OXBUDGET was developed for use with the GEOS-CTM,
            there might be some adaptation required for use with
            other models.  

        (2) Only 2 "families" are considered: Dry Deposition and Ox.

        (3) Wrapping around the date line seems to work but you
            should always double-check.

        (4) Currently, the box of consideration must be less than
            global size in order to m
       
 EXAMPLE:
        CTM_OXBUDGET, 'box1.ox', LogFileName='box1.log'
           
             ; Computes Ox budgets for the region specified in
             ; the file "box1.ox" and sends output to the 
             ; "box1.log" log file.

 MODIFICATION HISTORY:
        bmy, 28 Jan 2000: VERSION 1.00
                          - adapted original code from Isabelle Bey
        bmy, 25 May 2000: GAMAP VERSION 1.45
                          - now allow the user to specify diagnostic
                            category names in the batch file
                          - added internal function "TruncateAndWrapForOx"
                            to wrap arrays around the date line
                          - added internal procedure "ErrorOx"
                            to do error checking for CTM_GET_DATABLOCK
                          - now can create budgets for more than one
                            diagnostic interval  
                          - now allow user not to compute chemical 
                            production data for given families
        acs, 26 May 2000: - bug fixes: now do not stop the run if 
                            data blocks are not found.  
        bmy, 01 Aug 2000: GAMAP VERSION 1.46
                          - use abs( Total( X ) ) > 0 when testing if 
                            transport fluxes are all nonzero
        bmy, 13 Dec 2001: GAMAP VERSION 1.49
                          - Now do not require all transport fluxes
                            to be nonzero in order to compute budgets
                          - now truncate data blocks correctly for
                            E/W and N/S transport fluxes
                          - Now compute the total number of seconds
                            over the entire diagnostic interval
                          - Now divide fluxes by the number of diagnostic
                            time intervals in order to get average fluxes
        bmy, 17 Jan 2002: GAMAP VERSION 1.50
                          - now call STRBREAK wrapper routine from
                            the TOOLS subdirectory for backwards
                            compatiblity for string-splitting;
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10
        bmy, 23 Mar 2008: GAMAP VERSION 2.12
        phs, 20 Aug 2008: GAMAP VERSION 2.13
                          - now 3D region can be as small as one box.

(See /n/home09/ryantosca/IDL/gamap2/gamap_util/ctm_oxbudget.pro)


CTM_PLOT

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
        CTM_PLOT

 PURPOSE:
        General plotting tool for CTM data that is stored in the 
        GAMAP datainfo and fileinfo structures. CTM_PLOT can 
        handle everything from 0-D to 3-D and has many different
        plot options, especially for 2-D plots for which it was
        originally designed. E.g. full map support.

 CATEGORY:
        GAMAP Utilities, GAMAP Plotting

 CALLING SEQUENCE:
        CTM_PLOT, [ Diagn [ [ ,Keywords ] ] 

 INPUTS:
        DIAGN -> The diagnostic number (e.g. ND22, ND45, etc or 
             category name (e.g. "JV-MAP", "IJ-AVG") for which to 
             read data from the punch file. 

 KEYWORD PARAMETERS:
    Keyword parameters passed to CTM_GET_DATABLOCK:
    ===============================================
        FILENAME -> Name of the punch file to read data from.  
             FILENAME is passed to CTM_GET_DATABLOCK.  You can also
             use a file mask, in which case FILENAME will return the 
             full filename if it is a named variable. If an empty 
             filename is provided, the default search mask from 
             gamap.defaults (see gamap.cmn) will be used. If no 
             filename is given, ctm_plot will try 
             to find the records from data already loaded.

        TRACER -> Number of tracer to read from the punch file.

        TAU0, /FIRST, /LAST -> time step to be plotted

        LON -> If /INDEX is set, LON denotes the CTM longitude index
             of the box to plot.  Otherwise, LON denotes the actual
             longitude value of that box. (that is at box CENTER, phs
             4/2/08)

        LAT -> If /INDEX is set, LAT denotes the CTM latitude index
             of the box to plot.  Otherwise, LAT denotes the actual
             latitude value of that box. (that is at box CENTER, phs
             4/2/08)

        LEV -> An index array of sigma levels *OR* a two-element
             vector specifying the min and max sigma levels to be 
             included in the plot.  Default is [ 1, GRIDINFO.LMX ].
 
        ALTRANGE -> A vector specifying the min and max altitude
             values to be included in the extracted data block.

        PRANGE -> A vector specifying the min and max pressure 
             levels to be included in the extracted data block.

        /INDEX -> If set, will interpret LAT, LEV, and LON as CTM 
             indices.  If not set, will interpret LAT, LEV, and LON
             as the actual values of latitude, level, and longitude.
             NOTE: If /INDEX is set, then GAMAP cannot create plots
             for longitude ranges that span the date line!!!

        AVERAGE -> If = 0, will not average the data 
                      = 1, will average data longitudinally
                      = 2, will average data latitudinally
                      = 4, will average data vertically
             These are cumulative (e.g. AVERAGE=3 will average over 
             both lat and lon, and AVERAGE=7 will average over lat,
             lon, and vertical levels to produce 1 data point).
                       
        TOTAL -> If = 0, will not total data
                    = 1, will total data longitudinally
                    = 2, will total data latitudinally
                    = 4, will total data vertically
             These are cumulative (e.g. TOTAL=3 will total over both 
             lat and lon, and TOTAL=7 will total over lat, lon, and 
             vertical levels to produce 1 data point).

        USE_FILEINFO -> (optional) If provided, CTM_GET_DATABLOCK will 
             restrict its search to only the files that are
             contained in USE_FILEINFO which must be a FILEINFO 
             structure array. Default is to use the global information 
             (see gamap_cmn.pro).
             If an undefined named variable is provided in USE_FILEINFO,
             it will either contain the global FILEINFO structure array 
             or the FILEINFO record of the specified file.
             USE_FILEINFO and USE_DATAINFO must be consistent, and should
             either both be used or omitted. However, it is
             possible to provide the global FILEINFO structure 
             (or nothing) with a local subset of DATAINFO.

        USE_DATAINFO -> (optional) Restrict search to records contained
             in USE_DATAINFO which must be a DATAINFO structure array. 
             If an undefined named variable is provided in USE_DATAINFO,
             it will either contain the global DATAINFO structure array 
             or all DATAINFO records of the specified file.
             See also USE_FILEINFO.

    Keywords passed to CTM_CONVERT_UNIT:
    ====================================
        UNIT -> Name of the unit that the DATA array will be converted
             to. If not specified, then no unit conversion will be done.

    Keywords passed to TVMAP or TVPLOT:
    ===================================
        NOERASE -> Do not erase previous plot.
 
        POSITION -> A four-element array of normalized coordinates
             that specifies the location of map on the plot. POSITION
             has the same form as the POSITION keyword on a plot. 
             Default is [0.1, 0.05, 0.9, 0.08]. (Passed to TVMAP).

        NCOLORS -> This is the maximum color index that will be used.

        BOTTOM -> The lowest color index of the colors to be loaded
             used in the color map and color bar.

        /NOCBAR -> If set, will not plot the colorbar below the map
             in the position specified by CBPOSITION.  Default is to
             plot a colorbar.

        CBCOLOR -> Color index of the colorbar outline and
             characters.  Defaults to BLACK (from colors_default.pro).

        CBPOSITION -> A four-element array of normalized coordinates
             that specifies the location of the colorbar. BARPOSITION 
             has the same form as the POSITION keyword on a plot. 
             Default is [0.1, 0.05, 0.9, 0.08]. 

        CBUNIT -> Passes the Unit string to COLORBAR, which will be
             plotted to the right of the color bar.  NOTE: For black
             & white contour plots, the string specified by CBUNIT
             will be plotted below the X-axis.  

        CBFORMAT -> format to use in call to colorbar. Default is I12
             if abs(max(data)) < 1e4, else e12.2 (strings get trimmed)

        COLOR  -> Color index of the map outline and title characters.  
             Defaults to BLACK (from colors_default.pro). Also used as
             plot color for 1-D (line) plots.

        MPARAM -> A 3 element vector containing values for
             [ P0Lat, P0Lon, Rot ].  Default is [ 0, 0, 0 ].

        POSITION -> A four-element array of normalized coordinates
             that specifies the location of the map.  POSITION has
             the same form as the POSITION keyword on a plot. 
             Default is [0.1, 0.1, 0.9, 0.9]. 

        TITLE -> The title string that is to be placed atop the
             map window.  

        /NOCONTINENTS -> If set, will suppress adding continent lines
             to the map.  Default is to call MAP_CONTINENTS to plot
             continent outlines or filled boundaries.

        CCOLOR -> The color index of the continent outline or fill 
             region.  Default is BLACK (from colors_default.pro).
 
        CFILL -> Value passed to FILL_CONTINENTS keyword of
             MAP_CONTINENTS.  If CFILL=1 then will fill continents
             with a solid color (as specified in CCOLOR above).  
             If CFILL=2 then will fill continents with hatching.

        /NOGRID -> If set, will suppress printing of grid lines.
             Default is to call MAP_GRID to overlay grid lines.
 
        GCOLOR -> The color index of the grid lines.
             Default is BLACK (from colors_default.pro)

        /NOGLABELS -> Will suppres printing of labels for each grid
             line in TVMAP.PRO.  Default is to print grid labels
             for each grid line.

        /NOISOTROPIC -> Will suppress plotting of an isotropic map
             (i.e. one with the same X and Y scale).  Default is to 
             print an isotropic map.
  
        /CONTOUR -> Will produce a line-contour map instead of the 
             default color-pixel image map.

        /FCONTOUR -> Will produce a filled contour map instead
             of the default color-pixel image map. If you find
             that one or more color bands are not filled properly, 
             try the /CELL_FILL keyword. This is a known IDL precularity.

        C_LEVELS -> Vector containing the contour levels.  If not
             specified, TVMAP will use quasi-logarithmic levels.

        C_COLORS -> Index array of color levels for each line (or
             each fill section) of the contour map.  If not
             specified, TVMAP will select default colors from the 
             colortable.

        C_ANNOTATION -> Vector containing the contour labels.
             Default is to use string representations of C_LEVELS.

        C_FORMAT -> Format string used in converting C_LEVELS to
             the default C_ANNOTATION values.  Default is '(f8.1)'.

        C_LABELS -> Specifies which contour levels should be labeled.
             By default, every other contour level is labeled.  C_LABELS 
             allows you to override this default and explicitly
             specify the levels to label. This parameter is a vector, 
             converted to integer type if necessary.  If the LEVELS 
             keyword is specified, the elements of C_LABELS
             correspond directly to the levels specified, otherwise, 
             they correspond to the default levels chosen by the 
             CONTOUR procedure. Setting an element of the vector to 
             zero causes that contour label to not be labeled.  A
             nonzero value forces labeling. 

             NOTE: If C_LABELS is given as a scalar, then it will be
             expanded to a vector with all elements having the same value.

        /C_LINES -> Will overplot a filled-contour map with contour lines
             and labels instead of plotting a colorbar. This was the old
             default behaviour but has been changed with the advent of
             "discrete" colorbars. The old NOLINES keyword is kept
             for compatibility reasons but doesn't do anything.

        /NOLABELS -> Will suppress printing contour labels on both
             line-contour and filled-contour maps.

        OVERLAYCOLOR -> Color of the solid lines that will be
             overlaid atop a filled contour map.  Default is BLACK.

        /OVERPLOT -> Add an additional line plot to an existing one.
             You should specify LINE=n and/or COLOR=n to distinguish 
             between curves in this case. You can manually add a legend
             with legend.pro after the plot(s) are produced.
             Note that the title string will contain information on 
             your first selection only. Use an explicit TITLE for 
             best results.

        /SAMPLE -> Will cause REBIN (in TVMAP) to use nearest-
             neighbor sampling rather than bilinear interpolation.

        /LOG -> Will create a color-pixel plot with logarithmic
             scaling.  /LOG has no effect on line-contour or
             filled-contour plots, since the default contour levels
             are quasi-logarithmic.

        /POLAR -> Create a polar plot. Note that the longitude range must 
             be -180..180 and the latitude range must extend to one pole
             but not straddle the equator.


    Keywords passed to ISOPLETH_MAP:
    ================================
        ISOPLETH -> Value for which a 3-D isosurface will be computed.
             ISOPLETH_MAP assigns a default value of 35.0.  


    Other Keywords:
    ===============
        USTR -> Unit string to be plotted to the right of the colorbar.  
             If not specified, then CTM_PLOT  will construct a unit 
             string based on the value of TRACERINFO.UNIT.
             NOTE: USTR is a synonym for the keyword CBUNIT, which
             specifies the color bar unit string.

        THISDATAINFO -> Returns to the calling program the THISDATAINFO
             structure obtained by CTM_GET_DATABLOCK.

        LABELSTRU -> Returns to the calling program the structure
             of label information obtained by CTM_LABEL.
 
        YRANGE -> range of y values for color scaling (default:
             scale each plot seperately with data min and max)

        X_FORMAT, Y_FORMAT (optional) -> Specifies the format string
             (e.g. '(f10.3)', '(e14.2)' ) for the X and Y axes, when
             making line plots.  If omitted, CTM_PLOT will call
             GET_DEFAULTFORMAT to compute default format strings. 

        RESULT -> A named variable will contain the data subset that was
             plotted together with the X and/or Y coordinates in a structure.
             For 1D plots, either X or Y are -1. 3D visualization returns
             a structure including the Z coordinate.

        _EXTRA=e -> Picks up extra keywords for CTM_GET_DATABLOCK,
             CTM_LABEL, TVMAP, and TVPLOT.

 OUTPUTS:
        None

 SUBROUTINES:
        External Subroutines Required:
        ===========================================================
        CTM_DRAW_CUBE                  CONVERT_LON
        CTM_TRACERINFO                 CTM_CONVERT_UNIT
        TVMAP                          TVPLOT
        CHKSTRU           (function)   MYCT_DEFAULTS     (function)
        CTM_GET_DATABLOCK (function)   CTM_LABEL         (function) 
        REPLACE_TOKEN     (function)   CTM_BOXSIZE       (function)   
        GET_DEFAULTFORMAT (function)   GAMAP_CMN     (include file)   

        
 REQUIREMENTS:
        Also assumes colortable has been loaded with "myct.pro". 

 NOTES:
        (1) Some keywords are saved in local variables with 
        slightly different names (e.g. MCONTOUR for /CONTOUR) 
        to prevent confusion with routine names and/or keywords
        that are picked up by the _EXTRA=e facility.

        (2) Not every possible combination of keywords has been thoroghly 
        tested. *PLEASE* report reproducible errors to mgs@io.harvard.edu!!

        (3) As of 11/17/98, CTM_PLOT can only produce X-Y plots with
        either PRESSURE or ALTITUDE along the left Y-Axis.  The right
        Y-Axis is left disabled (but will fix that later on...) 

        (4) Now define X-axis labels for longitude.  The labels are
        defined correctly for data blocks that span the date line.

 EXAMPLE:
        (0)
        CTM_PLOT
             ; To plot an ozone surface map (default) of a 
             ; user-selected file

        (1)
        FileName = '~/terra/CTM4/run_code/ctm.pch.sep1'
        CTM_PLOT, 22, 1, FileName=FileName, Lev=[1,14], $
           Total=4, /NoErase 

             ; Plots vertically-summed map for tracer 1 of ND22
             ; (J-Values map).  Will erase screen before plotting map.

        (2)
        CTM_PLOT, 'JV-MAP-$', 1, FileName=FileName, Lev=[1,14], $
           Total=4, /NoErase 

             ; Same as above, but uses category name instead of 
             ; diagnostic number.
 

 MODIFICATION HISTORY:
        bmy, 21 Sep 1998: VERSION 1.00
        bmy, 22 Sep 1998: VERSION 1.01
                          - added AVERAGE and TOTAL keywords
        bmy, 22 Sep 1998: VERSION 1.10
                          - Modified for use with new versions of
                            CTM_GET_DATABLOCK, CTM_EXTRACT,
                            CTM_LABEL, REPLACE_TOKEN, and TVMAP
        bmy, 25 Sep 1998: VERSION 1.11
                          - modified for TVMAP v. 2.0
        bmy, 28 Sep 1998: VERSION 2.00
                          - modified for TVMAP v. 2.01
                          - renamed LONSHIFT to LSHIFT
        bmy, 29 Sep 1998: - added ALTRANGE and PRANGE keywords
                            (which had been previously omitted)
        bmy, 30 Sep 1998: VERSION 2.01
                          - added call to CTM_CONVERT_UNIT
                          - added LABELSTRU keyword 
        bmy, 07 Oct 1998  VERSION 2.02
                          - now works with TVMAP 3.0
                          - added /CONTOUR, /FCONTOUR, and 
                            /COLORBAR keywords
                          - removed I/O error handling (that 
                            is already done in CTM_GET_DATABLOCK)
        bmy, 08 Oct 1998: VERSION 2.03
                          - now works with CTM_GET_DATABLOCK v. 1.03
                            and CTM_EXTRACT v. 1.04
                          - added DATA and THISDATAINFO keywords so
                            that an external data block can be
                            passed.
                          - another bug fix for UNITSTR
        bmy, 03 Nov 1998: VERSION 2.04
                          - works with new CTM_GET_DATA, 
                            CTM_GET_DATABLOCK and CTM_LABEL routines
                          - Now pass the FILEINFO and DATAINFO
                            structures via USE_FILEINFO and
                            USE_DATAINFO keywords
                          - removed DATA keyword   
                          - changed %NAME% token to %TRACERNAME%
                          - Now can pass an explicit unit string
                            via the USTR keyword
        mgs, 10 Nov 1998: - adapted for use with new CTM_GET_DATABLOCK
                          - changed keyword Erase to NoErase
                          - defaults set to produce an OX surface map
                            from IJ-AVG-$ diagnostics 
                          - allow for vertical cross section plots
                            (interface to TVPLOT) : ** still needs work! **
                          - changed CBAR to NOCBAR
        bmy, 12 Nov 1998: - TRACER is now a keyword instead of
                            an argument
                          - Changed keyword CONTINENTS to
                            NOCONTINENTS and GRID to NOGRID
                          - added NOISOTROPIC, SAMPLE and
                            keywords
        bmy, 13 Nov 1998: - VERSION 3.00
                          - ***** RENAMED to CTM_PLOT *****
                          - updated documentation header
                          - renamed C_LABELS to C_ANNOTATION to
                            prevent keyword name confusion
                          - added NOLINES, NOLABELS, C_LABELS,
                            and OVERLAYCOLOR keywords for tvmap
                          - now gets default colors from 
                            DEFAULT_COLORS.PRO
                          - Error checking for LIMIT keyword
                            (OK for now...fix this later on...)
        bmy, 16 Nov 1998: - Now use %DATE% instead of %YMD1% for
                            all default plot titles
                          - now enhanced for TVPLOT v. 2.0
                          - now only convert units for a tracer 
                            if the default unit is different from
                            the desired unit!!
        bmy, 17 Nov 1998: - added /PRESSURE keyword to plot pressure
                            instead of altitude on the left Y-axis
        mgs, 17 Nov 1998: - messed around quite a bit, because of 
                            (unfortunate) changes in default_range !@#$!@
                          - added CBFormat keyword
        bmy, 23 Nov 1998: - eliminated %SCALE% token from UNITSTR,
                            to be consistent with the latest
                            upgrade to COLORBAR.PRO. 
                          - now pass SECONDS to CTM_CONVERT_UNIT
        bmy, 13 Jan 1999: - add support for line plots.  Also, if
                            the DATA array is averaged down to a
                            single point, will print the value of
                            that point and exit.
                          - use NEWXTITLE and NEWYTITLE as token-replaced
                            strings for XTITLE and YTITLE
        bmy, 15 Jan 1999: - add support for 3-D visualization plots
                          - added unit string for contour plots
                          - now place CTM_LABEL call after the case
                            statement for PLOTTYPE, so that we can
                            suppress printing of special characters
                            in plot titles.
        bmy, 19 Jan 1999: - improve 0-D output
                          - fixed [XY]Titles for line plots
                          - "unitless" is now a unit string option
                          - now use new default color names from
                            DEFAULT_COLORS.PRO
        bmy, 20 Jan 1999: - Updated comments
        mgs, 22 Jan 1999: - couple bug fixes, some code cleaning
                          - added OverPlot keyword to allow multiple
                            line plots
        bmy, 19 Feb 1999: - now pass DEBUG (from GAMAP_CMN) to 
                            CTM_GET_DATABLOCK via DEBUG keyword
                          - Rename XIND, YIND, ZIND keywords to
                            XMID, YMID, ZMID, in call to CTM_GET_DATABLOCK
        bmy, 23 Feb 1999: - Add XTICKNAME, XTICKS, XTICKV in call to
                            TVPLOT...fix for map regions smaller than 
                            the globe
                          - bug fix.../NOGRID was listed as GRID!!!
                          - added keyword /NOGLABELS, which
                            suppresses grid line labels in MAP_SET 
                          - updated comments
        bmy, 26 Feb 1999: - now calls MAP_LABELS to get latitude labels
                            for X, XZ, Y, YZ plot types.
                          - updated comments
        bmy, 04 Mar 1999: - now pass DEBUG keyword to TVMAP
                          - now use GRIDINFO.XEDGE, GRIDINFO.YEDGE
                            to compute the LIMIT keyword for MAP_SET
        mgs, 18 Mar 1999: - minor cleaning
        mgs, 23 Mar 1999: - added ILun to keyword list to prevent retrieval
                            of two otherwise identical records from two
                            different files
        bmy, 25 Mar 1999: - now line plots use MULTIPANEL
                          - if NPANELS >=2 then place the plot title
                            higher above the window, to allow for 
                            carriage-returned lines
                            for X, Y, Z, XY, XZ, YZ plots
        mgs, 25 Mar 1999: - no unit conversion if not necessary
                          - small fix to allow for 2D fields (e.g. EPTOMS)
        bmy, 14 Apr 1999: - now prints unit string at lower right of
                            XZ or YZ plots, if the colorbar is not
                            plotted
        bmy, 26 Apr 1999: - rename YRANGE to YYRANGE internally, so as
                            to avoid confusion with YRANGE plot keywords   
        mgs, 19 May 1999: - removed a few too explicit keyword settings
                            for 1D plots and fixed OverPlot option.
                            Now stores !X, !Y, and !P from last 1D plot
                            in a local common block.
        mgs, 21 May 1999: - restore !X, !Y, and !P at the end of each
                            1-D plot to allow overplotting of data.
        mgs, 25 May 1999: - needed to mess around with lonrange to get
                            it right.
        mgs & bmy, 26 May 1999: - added POLAR keyword
        bmy, 27 May 1999: - bug fix: CBUnit keyword wasn't honored
                          - neither was NoIsotropic
        mgs, 27 May 1999: - changed default behaviour for filled contours:
                            now plots no lines and colorbar. Keyword
                            NoLines changed to C_Lines.
        mgs, 28 May 1999: - added RESULT keyword to return data as plotted
                          - bug fix with wrapping round data: shouldn't be
                            done for vertical cross sections.
        mgs, 02 Jun 1999: - small bug fix for 0D results.
        mgs, bmy 03 Jun 1999: - removed "Unit:" from output
        bmy, 07 Jul 1999: - added PLOTCSFAC scale factor for multipanel
                            plots
                          - small fixes for line plots
        bmy, 02 Nov 1999: GAMAP VERSION 1.44
                          - return if THISDATAINFO contains
                            information for more than one data block
        bmy, 24 Nov 1999: - now pass _EXTRA=e to CTM_TRACERINFO
                            so that /SMALLCHEM will be passed
        bmy, 13 Dec 1999: - if GRIDINFO is undefined after returning from
                            CTM_GET_DATABLOCK, rebuild it w/ CTM_TYPE
        bmy, 03 Feb 2000: GAMAP VERSION 1.45
                          - NOTE: /INDEX does not work with lon range
                            shifting anymore.  Will fix later.
                          - also make sure LON, LAT have two elements 
                          - added X_FORMAT, Y_FORMAT keywords for line plots
                          - updated comments 
        bmy, 06 Apr 2000: - bug fix: restrict X or Y axis range for line
                            plots using the value passed from YYRANGE.
                          - cosmetic changes, updated comments
        bmy, 23 Jan 2001: GAMAP VERSION 1.47
                          - now call "isopleth_map.pro" to plot a 3-D
                            isosurface.  3-D visualization via
                            routine "ctm_draw_cube.pro" is obsolete.
                          - added ISOPLETH keyword as pass-thru to 
                            ISOPLETH_MAP
        bmy, 23 Jul 2001: GAMAP VERSION 1.48
                          - replaced call to DEFAULT_COLORS with 
                            call to MYCT_DEFAULTS() to specify
                            MYCT color table information
                          - deleted obsolete code from 1998 and 1999
        bmy, 09 Aug 2001: - bug fix: remove reference to BLACK from
                            the old "default_colors.pro"
        bmy, 24 May 2002: GAMAP VERSION 1.50
                          - Now use SI unit hPa instead of mb in axis titles
                          - delete obsolete, commented-out code
        bmy, 28 Sep 2002: GAMAP VERSION 1.51
                          - now get default NCOLORS, BOTTOM, BLACK values
                            from !MYCT system variable instead of from
                            the MYCT_DEFAULTS function
        bmy, 16 Apr 2004: GAMAP VERSION 2.02
                          - Also need to convert the units of YYRANGE
                            accordingly so that /AUTORANGE will work
        bmy, 16 Jun 2004: - Bug fix: if we do unit conversion, do not
                            let the converted value of YRANGE get
                            passed back to the main program
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10
                          - Modified for GEOS-5 fields that are
                            defined on level edges
        phs, 19 Mar 2008: GAMAP VERSION 2.12
                          - Bug fix for working with new map_labels
        phs, 02 Apr 2008: - Bug fix for XZ and YZ pixel plots

(See /n/home09/ryantosca/IDL/gamap2/gamap_util/ctm_plot.pro)


CTM_PLOTDIFF

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
        CTM_PLOTDIFF

 PURPOSE:
        Prints a lat-lon map of 2 CTM fields, their absolute difference, 
        and their percent difference.  This is a quick way of ensuring 
        that two model versions are producing identical results.

        The page will contain the following plot panels:

             Panel #1               Panel #2
             Data Block D1          Data Block D2

             Panel #3               Panel #4
             Abs Diff (D2 - D1)     % Diff (D2 - D1)

 CATEGORY:
        GAMAP Utilities, GAMAP Plotting

 CALLING SEQUENCE:
        CTM_PLOTDIFF, DIAGN, FILE1, FILE2 [, Keywords ]

 INPUTS:
        DIAGN -> A diagnostic number or category to restrict
             the record selection (default is: "IJ-AVG-$"). 

        FILE1 -> Name of the first CTM output file.  If FILE1
             is not given, or if it contains wildcard characters
             (e.g. "*"), then the user will be prompted to supply
             a file name via a pickfile dialog box.

        FILE2 ->  Name of the second CTM output file.  If FILE2
             is not given, or if it contains wildcard characters
             (e.g. "*"), then the user will be prompted to supply
             a file name via a pickfile dialog box.

 KEYWORD PARAMETERS:


        LON -> A 2-element vector specifying the longitude range that
             will be used to make the plot.  Default is [-180,180].

        LAT -> A 2-element vector specifying the latitude range that
             will be used to make the plot.  Default is [-88,88].

        LEV -> A scalar or 2-element vector which specifies the
             level(s) that will be used to make the plot.  Default
             is [ 1, 1 ].

        /PS -> Set this switch to print to a PostScript file.
 
        OUTFILENAME -> Name of the PostScript file if the /PS option 
             is set.  Default is "idl.ps".

        TRACER -> Tracer number(s) for which differences will be plotted.  

        TAU0 -> TAU value(s) (hours since 0 GMT 1 Jan 1985) at the start
             of the diagnostic data block to plot.

        DIVISIONS -> Specifies the number of colorbar divisions for 
             the quantity plot (Panels #1 and #2).  Default is 5.
             NOTE: The optimal # of divisions is !MYCT.NCOLORS/2 +1.

        DATARANGE -> Allows you to manually specify the min and max
             values of the data that will appear on the plot (Panels
             # 1 and #2).  The default is to automatically compute
             the overall min and max of both data blocks.

        MIN_VALID -> Specifies the minimum valid data for the plot. 
             Data lower than MIN_VALID will be rendered with color
             !MYCT.WHITE.  For example, MIN_VALID is useful for
             plotting emissions which only occur on land.

        DIFFDIV -> Specifies the number of colorbar divisions for 
             the difference plots (Panels #3 and #4).  Default is 8.
             NOTE: The optimal # of divisions is !MYCT.NCOLORS/2 +1.

        DIFFNCOLORS -> Sets the # of colors used to create the
             difference plots (Panels #3 and #4).  Default is 13.

        DIFFRANGE -> Allows you to manually specify the min and max
             values that will appear on the absolute difference
             plot (Panel #3).  Default is to use the dynamic range of
             the absolute difference data (symmetric around zero).

        /NODEVICE -> set to not call open_device, so you can do it
             from outside

        /NOMULTIPANEL -> set to not call multipanel, so you can do it
             from outside

        PCRANGE -> Allows you to manually specify the min and max
             values that will appear on the percentage difference
             plot (Panel #4).  Default is to use the dynamic range of
             the percentage difference data (symmetric around zero).

        PCDIV -> number of ticks in the %-Diff colorbar

        PCNCOLORS -> number of colors for the %-Diff plot

        T1, T2, DIFFTITLE -> allows you to overwrite the default
             title for the 1st, 2nd and DIff plots.


        _EXTRA=e -> Picks up extra keywords for CTM_DIFF,
             OPEN_DEVICE, and MYCT


   Keywords for the MASK feature:
   ------------------------------
        /MASK -> set to mask with a green color boxes where %-diff
             and/or diff are below some threshold. The absolute value
             of the % is plot.

	 PC_THR, DIFF_THR : the %-Diff and Diff THResholds to mask data in the
             4th plot if /MASK is set. Boxes with %-Diff or/and Diff
             below the THResholds are masked. Default values are 1%
             and 1e4.

        /ZAP -> set to skip all plots if /MASK is set and all boxes
             are masked.


 OUTPUTS:
        none

 SUBROUTINES:
        External Subroutines Required:
        =======================================================
        CHKSTRU     (function)    CLOSE_DEVICE 
        CTM_CLEANUP               COLORBAR_NDIV     (function)
        CTM_DIFF                  CTM_GET_DATABLOCK (function) 
        IS_DEFINED   (function)   EXTRACT_FILENAME  (function) 
        MULTIPANEL                OPEN_DEVICE
        

 REQUIREMENTS:
        None

 NOTES:
        (1) CTM_PLOTDIFF calls CTM_CLEANUP each time to remove
            previously read datablock info from the GAMAP common
            block.

        (2) The default TAU0 value is 0, and is not suitable if your 
            run has no output for 0 GMT 1 Jan 1985! You may have to 
            gather tau0 before running and crashing CTM_PLOTDIFF.

 EXAMPLE:
        FILE1 = 'ctm.bpch.v4-30'
        FILE2 = 'ctm.bpch.v4-31'
        CTM_PLOTDIFF, 'IJ-AVG-$', FILE1, FILE2, TRACER=1

             ; Creates 4-panel plot w/ old data, new data,
             ; new - old (abs diff), and new - old (% diff).

 MODIFICATION HISTORY:
        bmy, 17 Apr 2002: GAMAP VERSION 1.50
        bmy, 17 Jul 2002: GAMAP VERSION 1.51
                          - added TAU0 keyword
        bmy, 16 Dec 2002: GAMAP VERSION 1.52
                          - now can handle 2 different tracer numbers
                          - now can handle 2 different TAU0 values
        bmy, 29 Jan 2004: GAMAP VERSION 2.01
                          - Now pass LEV keyword to CTM_DIFF
                          - Now plot both DATA1 and DATA2 on
                            the same scale for easier comparison
        bmy, 16 Feb 2005: GAMAP VERSION 2.03
                          - Now use /QUIET and /NOPRINT keywords in
                            CTM_GET_DATA and CTM_GET_DATABLOCK to
                            suppress screen output
        phs, 24 Oct 2006: GAMAP VERSION 2.05
                          - Now use YRANGE if it is passed.  
                          - Also use DIFFRANGE (for range of the 
                            abs difference plot) if it is passed.
                          - Now use PCRANGE (for range of the
                            %age difference plot) if it is passed.
        bmy, 15 Nov 2006: GAMAP VERSION 2.06
                          - Now use blue-white-red color table
                            for abs diff and % diff plots
  bmy & phs, 04 Oct 2007: GAMAP VERSION 2.10
                          - Added DIVISIONS keyword (default=5) 
                          - Now make the default DIFFRANGE and
                            PCRANGE symmetric around zero
                          - Added DIFFDIV, DIFFNCOLORS keywords
                          - Also restore original !MYCT structure
                          - restore initial Color Table and !MyCt,
                            and return, when crashes.
                          - Now skip plotting % difference if
                            DATA1 is zero everywhere
                          - Add error trapping with CATCH
        bmy, 16 Jan 2008: GAMAP VERSION 2.12
                          - add _EXTRA=e to calls to CTM_PLOT, in order
                            to pass extra variables to that routine
        phs, 31 Jan 2008: - Add NODEVICE keyword, so device (like PS
                            file) can be open outside this routine,
                            allowing for multiple pages in a PS file
                            for example.
                          - Clipping of percentage difference range
                            is indicated with triangle.
        phs, 25 Feb 2008: - Improved error catcher
        bmy, 05 Nov 2008: GAMAP VERSION 2.13
                          - Renamed YRANGE keyword to DATARANGE in
                            order to avoid confusion with nested grids
        phs, 22 Sep 2009: - more flexible call to MYCT for diff
                            plots, so it can be overwriten from
                            caller
                          - Can select number of colors and divisions
                            for %-diff plot
                          - Can overwrite titles
                          - Can set Multipanel from outside in caller
                          - Can MASK data according to both Diff and
                            %-Diff values, in the 4th plot
        bmy, 29 Jan 2010: GAMAP VERSION 2.14
                          - Minor fix in IF statement to prevent code
                            from dying after call to CTM_DIFF.
                          

(See /n/home09/ryantosca/IDL/gamap2/gamap_util/ctm_plotdiff.pro)


CTM_PLOTDIFF4

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
        CTM_PLOTDIFF4

 PURPOSE:
        Prints a lat-lon map of 2 CTM fields, their absolute difference, 
        and their percent difference.  This is a quick way of ensuring 
        that two model versions are producing identical results.

        The page will contain the following plot panels:

             Panel #1               Panel #2
             Data Block D1          Data Block D2

             Panel #3               Panel #4
             Abs Diff (D2 - D1)     % Diff (D2 - D1) / D1

        CTM_PLOTDIFF4 is a lighter version of CTM_PLOTDIFF, and does
        not use CTM_DIFF as an intermediary routine. 

 CATEGORY:
        GAMAP Utilities, GAMAP Plotting

 CALLING SEQUENCE:
        CTM_PLOTDIFF4, DIAGN, FILE2, FILE2 [, Keywords ]

 INPUTS:
        DIAGN -> A diagnostic number or category to restrict
             the record selection (default is: "IJ-AVG-$"). 

        FILE1 -> Name of the first CTM output file.  If FILE1
             is not given, or if it contains wildcard characters
             (e.g. "*"), then the user will be prompted to supply
             a file name via a pickfile dialog box.

        FILE2 ->  Name of the second CTM output file.  If FILE2
             is not given, or if it contains wildcard characters
             (e.g. "*"), then the user will be prompted to supply
             a file name via a pickfile dialog box.

 KEYWORD PARAMETERS:

        LON -> A 2-element vector specifying the longitude range that
             will be used to make the plot.  Default is [-180,180].

        LAT -> A 2-element vector specifying the latitude range that
             will be used to make the plot.  Default is [-88,88].

        LEV -> A scalar or 2-element vector which specifies the
             level(s) that will be used to make the plot.  Default
             is [ 1, 1 ].

        /PS -> Set this switch to print to a PostScript file.
 
        OUTFILENAME -> Name of the PostScript file if the /PS option 
             is set.  Default is "idl.ps".

        TRACER -> A scalar or 2-element vector which specifies the
             tracer number(s) for each data block.  

        TAU0 -> A scalar or 2-element vector which specifies the
             TAU value(s) (hours since 0 GMT 1 Jan 1985) by which
             each data block is timestamped.

        DIVISIONS -> Specifies the number of colorbar divisions for 
             the quantity plot (Panels #1 and #2).  Default is 5.
             NOTE: The optimal # of divisions is !MYCT.NCOLORS/2 +1.

        DATARANGE -> Allows you to manually specify the min and max
             values of the data that will appear on the plot (Panels
             # 1 and #2).  The default is to automatically compute
             the overall min and max of both data blocks.

        MIN_VALID -> Specifies the minimum valid data for the plot. 
             Data lower than MIN_VALID will be rendered with color
             !MYCT.WHITE.  For example, MIN_VALID is useful for
             plotting emissions which only occur on land.

        DIFFDIV -> Specifies the number of colorbar divisions for 
             the difference plots (Panels #3 and #4).  Default is 8.
             NOTE: The optimal # of divisions is !MYCT.NCOLORS/2 +1.

        DIFFNCOLORS -> Sets the # of colors used to create the
             difference plots (Panels #3 and #4).  Default is 13.

        DIFFRANGE -> Allows you to manually specify the min and max
             values that will appear on the absolute difference
             plot (Panel #3).  Default is to use the dynamic range of
             the absolute difference data (symmetric around zero).

        /NODEVICE -> set to not call open_device, so you can do it
             from outside

        /NOMULTIPANEL -> set to not call multipanel, so you can do it
             from outside

        PCRANGE -> Allows you to manually specify the min and max
             values that will appear on the percentage difference
             plot (Panel #4).  Default is to use the dynamic range of
             the percentage difference data (symmetric around zero).

        PCDIV -> number of ticks in the %-Diff colorbar

        PCNCOLORS -> number of colors for the %-Diff plot

        TITLE_1 -> Allows you to override the default plot title for
             the first data block (1st plot panel).

        TITLE_1 -> Allows you to override the default plot title for
             the 2nd data block (2nd plot panel).

        DIFFTITLE -> Allows you to override the default plot title for
             the absolute difference plot (3rd plot panel).

        PCTITLE -> Allows you to override the default plot title for
             the percent difference plot (4th plot panel).

        _EXTRA=e -> Picks up extra keywords for CTM_DIFF,
             OPEN_DEVICE, and MYCT


   Keywords for the MASK feature:
   ------------------------------
        /MASK -> set to mask with a green color boxes where %-diff
             and/or diff are below some threshold. The absolute value
             of the % is plot.

	 PC_THR, DIFF_THR : the %-Diff and Diff THResholds to mask
	      data in the 4th plot (percent difference) if /MASK is
	      set.  Boxes with %-Diff or/and Diff below the THResholds
	      are masked. Default values are 1% and 1e4.

        /ZAP -> set to skip all plots if /MASK is set and all boxes
             are masked.;

 OUTPUTS:
        None

 SUBROUTINES:
        External Subroutines Required:
        ==========================================================
        CHKSTRU          (function)  CLOSE_DEVICE
        COLORBAR_NDIV    (function)  CTM_GET_DATABLOCK (function)
        EXTRACT_FILENAME (function)  MULTIPANEL                
        MYCT                         OPEN_DEVICE               
        TVMAP                        UNDEFINE

 REQUIREMENTS:
        Requires routines from the GAMAP package.

 NOTES:
        (1) When plotting a subset of the globe, CTM_PLOTDIFF4
            properly sets the colorbar ranges for the abs diff
            and percent diff plots.  This was an issue in the
            older CTM_PLOTDIFF.

        (2) Longitude and latitude ranges specified by LON and LAT
            will be applied to both data blocks.  

 EXAMPLE:
         CTM_PLOTDIFF4, 'IJ-AVG-$',                      $
                        'v8-03-02.bpch', 'v9-01-01.bpch, $
                        TRACER=6,      LEVEL=1,          $
                        LON=[-90,-30], LAT=[30,15]
 
             ; Creates a 4-panel difference plot for ISOPRENE
             ; (IJ-AVG-$, tracer #6) at the surface for the Amazon
             ; basin region from data in 2 different model versions.

 MODIFICATION HISTORY:
        bmy, 16 May 2011: VERSION 1.00
        bmy, 13 Jan 2014: GAMAP VERSION 2.17
                          - Bug fix: For 2-D data blocks that lack the  
                            GRIDINFO.ZMID tag name, display the altitude
                            of the data as 0.0 km.

(See /n/home09/ryantosca/IDL/gamap2/gamap_util/ctm_plotdiff4.pro)


CTM_PLOTRATIO

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
        CTM_PLOTRATIO

 PURPOSE:
        Plots the ratio of two CTM data fields.  This is one way
        to see if two model versions produce identical results.

 CATEGORY:
        GAMAP Utilities, GAMAP Plotting

 CALLING SEQUENCE:
        CTM_PLOTRATIO, DIAGN [, Keywords ]

 INPUTS:
        DIAGN -> A diagnostic number or category to restrict
             the record selection.  Default is "IJ-AVG-$". 

 KEYWORD PARAMETERS:
        FILE1 -> Name of the first CTM output file (containing the
             "old" data).  If FILE1 is not given, or if it contains 
             wildcard characters (e.g. "*"), then the user will be 
             prompted to supply a file name via a pickfile dialog box.

        FILE2 ->  Name of the second CTM output file.  If FILE2
             is not given, or if it contains wildcard characters
             (e.g. "*"), then the user will be prompted to supply
             a file name via a pickfile dialog box.

        LON -> A 2-element vector specifying the longitude range that
             will be used to make the plot.  Default is [-180,180].

        LAT -> A 2-element vector specifying the latitude range that
             will be used to make the plot.  Default is [-88,88].

        LEV -> Vertical level for which to plot data.  Default is 1.

        TITLE -> Title string for the plot.  If not specified, a
             generic title string will be generated.

        TRACER -> Number of the tracer for which differences
             will be plotted.  Default is 1.

        _EXTRA=e -> Picks up extra keywords for CTM_DIFF.

 OUTPUTS:
        None

 SUBROUTINES:
        External Subroutines Required:
        ==========================================
        CTM_CLEANUP   CTM_GET_DATABLOCK (function)
        CTM_DIFF      EXTRACT_FILENAME  (function)
        OPEN_DEVICE   CLOSE_DEVICE
        MULTIPANEL

 REQUIREMENTS:
        None

 NOTES:
        (1) The ratio plotted will be DATA2 / DATA1, where DATA2
            is contained in FILE2, and DATA1 is contained in FILE1.

        (2) For places where DATA1 = 0, DATA2 will also be set to 0.
            This avoids division by zero errors.

        (3) CTM_PLOTRATIO calls CTM_CLEANUP each time to remove
            previously read datablock info from the GAMAP common
            block.

 EXAMPLE:
        FILE1 = 'ctm.bpch.v4-30'
        FILE2 = 'ctm.bpch.v4-31'
        CTM_PLOTRATIO, 'IJ-AVG-$', $
             FILE1=FILE1, FILE2=FILE2, TRACER=1, LEV=1

             ; Plots the ratio of NOx data at the surface:
             ;   ctm.bpch.v4-31 / ctm.bpch.v4-30

 MODIFICATION HISTORY:
        bmy, 24 Apr 2002: GAMAP VERSION 1.50
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10

(See /n/home09/ryantosca/IDL/gamap2/gamap_util/ctm_plotratio.pro)


CTM_PLOT_TIMESERIES

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
        CTM_PLOT_TIMESERIES

 PURPOSE:
        Plots station timeseries data (e.g. from the GEOS-CHEM
        ND48 diagnostic) contained in binary punch file format.
        %%%% MAY NEED UPDATING %%%%%

 CATEGORY:
        GAMAP Utilities, GAMAP Plotting

 CALLING SEQUENCE:
        CTM_PLOT_TIMESERIES, CATEGORY [ , Keywords ] 

 INPUTS:
        CATEGORY -> The diagnostic number (e.g. ND22, ND45, etc or 
             category name (e.g. "JV-MAP-$", "IJ-AVG-$") for which to 
             read data from the punch file. 

 KEYWORD PARAMETERS:
        BOTTOM -> The lowest color index of the colors to be loaded
             used in the color map and color bar.  The default is
             to use the value in system variable !MYCT.BOTTOM.

        COLOR -> Color of the plot window and/or data.  The default
             is to use the system variable !MYCT.BLACK.

        LABELSTRU -> Returns to the calling program the structure
             of label information obtained by CTM_LABEL.

        LEV -> An index array of sigma levels *OR* a two-element
             vector specifying the min and max sigma levels to be 
             included in the plot.  Default is [ 1, GRIDINFO.LMX ].
 
        OVERPLOT -> Plot data atop the previous plot window, instead
             of erasing the screen and plotting in a new window.

        RESULT -> A named variable will contain the data subset that
             was plotted together with the X and/or Y coordinates in
             a  structure.  

        TITLE -> Top title string for the plot.  If not passed, 
             then a default title string will be printed.

        UNIT -> Name of the unit that the DATA array will be converted
             to. If not specified, then no unit conversion will be done.

        XTITLE -> X-Axis title string for the plot.  If not passed, 
             then a default title string will be printed.

        YTITLE -> Y-Axis title string for the plot.  If not passed, 
             then a default title string will be printed.

        YRANGE -> range of y values for color scaling (default:
             scale each plot seperately with data min and max)

        _EXTRA=e -> Picks up extra keywords for routines called
             by CTM_PLOT_TIMESERIES.

 OUTPUTS:
        None

 SUBROUTINES:
        External Subroutines Required:
        ===========================================================
        CTM_GET_DATA              CTM_INDEX           (function)
        CTM_LABEL    (function)   GETMODELANDGRIDINFO (function)
        UNDEFINE                  REPLACE_TOKEN       (function)         

 REQUIREMENTS:
        None

 NOTES:
        None

 EXAMPLE:

 MODIFICATION HISTORY:
        bmy, 16 Apr 2004: GAMAP VERSION 2.03
                          - Initial version
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10

(See /n/home09/ryantosca/IDL/gamap2/gamap_util/ctm_plot_timeseries.pro)


CTM_PRINTDIFF

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
        CTM_PRINTDIFF

 PURPOSE:
        Prints the sum of the differences between two CTM
        output files.  This is a quick way of ensuring that
        two model versions are producing identical results.

 CATEGORY:
        GAMAP Utilities, GAMAP Data Manipulation

 CALLING SEQUENCE:
        CTM_PRINTDIFF, DIAGN [, Keywords ]

 INPUTS:
        DIAGN -> A diagnostic number or category to restrict
             the record selection (default is: "IJ-AVG-$").        

 KEYWORD PARAMETERS:
        FILE1 -> Name of the first CTM output file (the "old" file).
             If FILE1 is not given, or if it contains wildcard 
             characters (e.g. "*"), then the user will be prompted 
             to supply a file name via a pickfile dialog box.

        FILE2 ->  Name of the second CTM output file (the "new" file).  
             If FILE2 is not given, or if it contains wildcard 
             characters (e.g. "*"), then the user will be prompted 
             to supply a file name via a pickfile dialog box.

        TRACER -> Number of the tracer for which differences
             will be plotted.

        _EXTRA=e -> Picks up other keywords for CTM_GET_DATABLOCK.

 OUTPUTS:
        Prints the quantity:

             DIFF[L] = TOTAL( DATA2[*,*,L] - DATA1[*,*,L] ) 

        for each level L.  If DIFF[L] = 0 for all levels L, then
        FILE1 and FILE2 contain identical data.

 SUBROUTINES:
        External Subroutines Required:
        ==============================
        CTM_CLEANUP
        CTM_GET_DATABLOCK (function)

 REQUIREMENTS:
        None

 NOTES:
        (1) If DATA1 corresponds to the "old" data, and DATA2
            corresponds to the "new" data, then CTM_DIFF will 
            compute the following:
         
            Abs. Diff = ( new - old )

        (2) CTM_PRINTDIFF calls CTM_CLEANUP each time to remove
            previously read datablock info from the GAMAP common
            block.

 EXAMPLE:
        FILE1 = 'ctm.bpch.v4-30'      ; the "old" file
        FILE2 = 'ctm.bpch.v4-31'      ; the "new" file
        CTM_PRINTDIFF, 'IJ-AVG-$', $
             FILE1=FILE1, FILE2=FILE2, TRACER=1

        IDL prints:
             Level:  26 Difference: -2.3841858e-07
             Level:  25 Difference:  0.0000000e+00
             Level:  24 Difference:  0.0000000e+00
             Level:  23 Difference:  0.0000000e+00
             Level:  22 Difference: -1.4901161e-08
             Level:  21 Difference:  0.0000000e+00
             Level:  20 Difference:  0.0000000e+00
             Level:  19 Difference:  0.0000000e+00
             Level:  18 Difference:  0.0000000e+00
             Level:  17 Difference:  0.0000000e+00
             Level:  16 Difference:  0.0000000e+00
             Level:  15 Difference:  0.0000000e+00
             Level:  14 Difference: -7.4505806e-09
             Level:  13 Difference:  0.0000000e+00
             Level:  12 Difference:  0.0000000e+00
             Level:  11 Difference:  0.0000000e+00
             Level:  10 Difference:  0.0000000e+00
             Level:   9 Difference:  0.0000000e+00
             Level:   8 Difference:  0.0000000e+00
             Level:   7 Difference:  0.0000000e+00
             Level:   6 Difference:  0.0000000e+00
             Level:   5 Difference:  0.0000000e+00
             Level:   4 Difference:  0.0000000e+00
             Level:   3 Difference:  0.0000000e+00
             Level:   2 Difference:  0.0000000e+00
             Level:   1 Difference:  0.0000000e+00

             ; Prints the sum of differences at each level 
             ; betweeen two GEOS-STRAT binary punch files 
             ; for NOx (tracer=1).
            
 MODIFICATION HISTORY:
        bmy, 04 Apr 2002: GAMAP VERSION 1.50
        bmy, 22 Apr 2002: - now takes diff of DATA2 - DATA1, in order
                            to be consistent with CTM_PLOTDIFF.
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10

(See /n/home09/ryantosca/IDL/gamap2/gamap_util/ctm_printdiff.pro)


CTM_PRINT_DATAINFO

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
        CTM_PRINT_DATAINFO

 PURPOSE:
        Create and print a formatted list of DATAINFO records.
        This procedure can be used for direct printing, but it
        can also return a string array of the formatted output 
        e.g. for use in a widget list.

 CATEGORY:
        GAMAP Internals, GAMAP Data Manipulation

 CALLING SEQUENCE:
        CTM_PRINT_DATAINFO,DATAINFO [,keywords]

 INPUTS:
        DATAINFO -> One or more DATAINFO records, e.g. the result 
             from CTM_GET_DATA.

 KEYWORD PARAMETERS:
        FIELDS -> (*** not yet implemented ***) A list of fields
             (structure tag names) to be printed. Default is
             CATEGORY, ILUN, TRACERNAME, TRACERNUMBER, 
             UNIT, TAU0, STATUS, DIMENSIONS
             FIELDS can also include tags from the (global) FILEINFO
             structure (e.g. FILENAME).

        OUTPUT -> A named variable that will contain a string array
             with the formatted output including the title line but 
             without the seperating lines. The title is not included
             if keyword /NOTITLE is set.

        /NOPRINT -> Don't print, only return formatted strings

        /NOTITLE -> Do not generate title line (will neither be printed
             nor included in OUTPUT.

 OUTPUTS:
        None

 SUBROUTINES:
        External subroutines required:  
        ------------------------------
        GAMAP_CMN  (include file)
        TAU2YYMMDD (function)

 REQUIREMENTS:
        References routines from both GAMAP and TOOLS packages.

 NOTES:
        For GISS, FSU family of models, TAU0 = 0 occurs on date 1/1/1980.
        For GEOS      family of models, TAU0 = 0 occurs on date 1/1/1985.
        Therefore, the model family must be obtained from the global
        FILEINFO structure in order to display the YYMMDD
        corresponding to TAU0.
 
 EXAMPLE:
        CTM_GET_DATA,DataInfo,File='',tracer=2
        CTM_PRINT_DATAINFO,DataInfo
        ; *or*
        CTM_PRINT_DATAINFO,DataInfo,Output=r,/NOPRINT

 MODIFICATION HISTORY:
        mgs, 10 Nov 1998: VERSION 1.00
        bmy, 11 Feb 1999: VERSION 1.01
                          - adjust format for double-precision TAU0
        mgs, 16 Mar 1999: - added tracer number and removed STATUS
                          - made cosmetic changes
        mgs, 23 Mar 1999: - print dimension as NA if not yet available
        bmy, 27 Apr 1999: - widen tracer number field to 6 chars
        mgs, 22 Jun 1999: - widen unit field to 12 chars and add DATE field
        bmy, 27 Jul 1999: VERSION 1.42
                          - GISS/FSU YYMMDD values are now correct
                          - cosmetic changes
        bmy, 10 Aug 1999: - change I6 format for date to I6.6
                            so that leading zeroes are printed
        bmy, 03 Jan 2000: VERSION 1.44
                          - change I6.6 format to I8.8 and print the 
                            date in YYYYMMDD format for Y2K compliance
                          - declare TAU2YYMMDD as external with the
                            FORWARD_FUNCTION command
        bmy, 14 Feb 2001: GAMAP VERSION 1.47
                          - decrease tracer name from 10 to 7 chars
                          - Now use 10-digit date string YYYYMMDDHH
        bmy, 02 Jul 2001: GAMAP VERSION 1.48
                          - now assume that GENERIC grids use GEOS
                            time epoch for NYMD2TAU 
        bmy, 21 Oct 2002: GAMAP VERSION 1.52
                          - now assume MOPITT grid uses GEOS epoch
                          - deleted obsolete code
        bmy, 03 May 2005: GAMAP VERSION 2.04
                          - wrap tracer number into 5 digits
                          - GCAP uses the same TAU values as GEOS models
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10
         bmy 24 Jan 2014: GAMAP VERSION 2.17
                          - Adjust output format string to allow for
                            a few extra spaces in UNIT and TRACER #.

(See /n/home09/ryantosca/IDL/gamap2/internals/ctm_print_datainfo.pro)


CTM_READ3DB_HEADER

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
        CTM_READ3DB_HEADER

 PURPOSE:
        retrieve header information and file positions of data
        blocks from binary global 3D model output. This is a
        twin of CTM_READ3DP_HEADER which digests the header
        information from ASCII punch files.

 CATEGORY:
        GAMAP Internals

 CALLING SEQUENCE:
        test = CTM_READ3DB_HEADER(LUN,FILEINFO,DATAINFO [,keywords])

 INPUTS:
        LUN --> logical file unit of the binary punch file. The file 
             must be open (see CTM_OPEN_FILE or OPEN_FILE)

        FILEINFO --> a (single) fileinfo structure containing information
             about the (open) file (see CREATE3DFSTRU). FILEINFO also
             contains information about the model which generated
             the output (see CTM_TYPE)

        DATAINFO --> a named variable that will contain an array of
             structures describing the file content (see
             CREATE3DHSTRU)

 KEYWORD PARAMETERS:
        PRINT  -> if activated, print all headers found in the file

 OUTPUTS:
        The function returns 1 if successful, and 0 otherwise. 

        FILEINFO --> toptitle and modelinfo tags will be set

        DATAINFO --> contains an array of named structures 
             (see CREATE3DHSTRU) with all relevant information
             from the punch file header and what is needed to find
             and load the data.
              
 SUBROUTINES:

 REQUIREMENTS:
        uses CREATE3DHSTRU function to create header structure
        uses CHKSTRU to test FILEINFO structure
        uses CTM_TYPE to create modelinfo structure
        needs gamap_cmn.pro to access global common block

 NOTES:
        This routine uses the new binary file format introduced
        first to the GEOS/Harvard CTM.

 EXAMPLE:
              fileinfo = create3dfstru()   ; not required !
              fname = '~bmy/terra/CTM4/results/ctm.bpch'
              open_file,fname,ilun,/F77_UNFORMATTED   ; <=== !!
              if (ilun gt 0) then $
                 result = CTM_READ3DB_HEADER(ilun,fileinfo,datainfo)
              print,result

        To get e.g. all scaling factors, type 
              print,datainfo[*].scale

        To retrieve the header structure for one data block, type
              blocki = datainfo[i]

 MODIFICATION HISTORY:
        mgs, 15 Aug 1998: VERSION 1.00
                          - derived from CTM_READ3DP_HEADER
        mgs, 21 Sep 1998: - changed gamap.cmn to gamap_cmn.pro
        mgs, 14 Jan 1999: - now expects diag category name instead 
                            of number
        bmy, 11 Feb 1999: - change TAU0, TAU1 to double-precision,
                            in accordance w/ new binary file format
                          - clean up some POINT_LUN calls
        bmy, 22 Feb 1999: VERSION 1.01
                          - now store I0, J0, L0 from binary file
                            in new FIRST field from CREATE3DHSTRU
                          - comment out assignment statement for
                            SKIP; now use value from binary file
        mgs, 16 Mar 1999: - cosmetic changes
        mgs, 24 May 1999: - now supports 'CTM bin 02' files
                          - added a filetype check
                          - now defaults to 512 records (former 4096)
        mgs, 27 May 1999: - fixed bug with new record default: new
                            records were never added as they were 
                            supposed to.
        bmy, 26 Jul 1999: - also print out SKIP field in debug output
        bmy, 10 Jul 2003: GAMAP VERSION 1.53
                          - added kludge so that GEOS-3 reduced grid
                            w/ 30 layers will be added to FILEINFO
                            correctly
        bmy, 21 Nov 2003: GAMAP VERSION 2.01
                          - BPCH file v1 now has FILETYPE=101
                          - BPCH file v2 now has FILETYPE=102
                          - Now define separate DATAINFO.FORMAT values
                            for BPCH v1 and BPCH v2 type files   
                          - removed kludge for GEOS3_30L, since the
                            bug in CTM_TYPE has now been fixed
        bmy, 24 Aug 2004: GAMAP VERSION 2.03
                          - now assign FORMAT string for Filetype 105
                            which is BPCH file for GEOS-CHEM station
                            timeseries (e.g. ND48 diagnostic)
  phs & bmy, 13 Jul 2007: GAMAP VERSION 2.10
                          - Now account for FILETYPE=106, which
                            denotes CTM bpch files w/ 4-D data.
        bmy, 23 Feb 2012: GAMAP VERSION 2.16
                          - Now make FILEPOS and NEWPOS LONG64
                            variables, in order to read bpch files
                            larger than 2.4 GB.
        bmy, 20 Jan 2016: GAMAP VERSION 2.19
                          - Bug fix: cast SKIP variable to LONG64

(See /n/home09/ryantosca/IDL/gamap2/internals/ctm_read3db_header.pro)


CTM_READ3DP_HEADER

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
        CTM_READ3DP_HEADER

 PURPOSE:
        retrieve header information and file positions of data
        blocks from global 3D model punch file output.

 CATEGORY:
        GAMAP Internals

 CALLING SEQUENCE:
        test = CTM_READ3DP_HEADER(LUN,FILEINFO,DATAINFO [,keywords])

 INPUTS:
        LUN --> logical file unit of the punch file. The file
             must be open (see CTM_OPEN_FILE or OPEN_FILE)

        FILEINFO --> a (single) fileinfo structure containing information
             about the (open) file (see CREATE3DFSTRU). FILEINFO also
             contains information about the model that generated the
             data, which is queried interactively.

        DATAINFO --> a named variable that will contain an array of
             structures describing the file content (see
             CREATE3DHSTRU)

 KEYWORD PARAMETERS:
        /NO_TOPTITLE --> do not interprete first line of file as
             header line. Only one header line will be skipped
             (as normally only one header line is read in).

        /EXTRA_SPACE -> digests output from GISS_II_PRIME model with
             extra spaces in the punch file. This keyword is optional
             in the following sense: If CTM_READ3DP_HEADER detects
             an error reading a header line, it is called again
             automatically with this option set.

        PRINT  -> if activated, print all headers found in the file

 OUTPUTS:
        The function returns 1 if successful, and 0 otherwise.

        FILEINFO --> toptitle and modelinfo tags will be set

        DATAINFO --> contains an array of named structures
             (see CREATE3DHSTRU) with all relevant information
             from the punch file header and what is needed to find
             and load the data.

 SUBROUTINES:

 REQUIREMENTS:
        uses CREATE3DHSTRU function to create header structure
        uses CHKSTRU to test FILEINFO structure
        uses CTM_TYPE to set modelinfo
        needs gamap_cmn.pro to set default in query for model type

 NOTES:
        This routine does rely on the output format from the global GCM
        as specified first for the GEOS/Harvard CTM. However, it is
        designed to digest the output from all models currently used
        in DJJ's group.
        It uses the NL parameter to skip blocks between headers.

        The window offsets (I0, J0, L0) are set to
        zero, since the ASCII punch file is not set up to save
        a sub-region of the globe (bmy, 2/11/99)

 EXAMPLE:
              fileinfo = create3dfstru()   ; not required !
              fname = '~bmy/terra/CTM4/results/ctm.pch.m2'
              open_file,fname,ilun
              if (ilun gt 0) then $
                 result = ctm_read3dp_header(ilun,fileinfo,datainfo)
              print,result

        To get e.g. all scaling factors, type
              print,datainfo[*].scale

        To retrieve the header structure for one data block, type
              blocki = datainfo[i]

 MODIFICATION HISTORY:
        mgs, 21 Aug 1997: VERSION 1.00
        mgs, 02 Mar 1998: VERSION 1.10
                  - can handle GEOS output now
                  - reads in file header
                  - returns structure instead of string array
                  - always returns all entries, filtering must be done later
        mgs, 03 Mar 1998: - now returns a structure and is a function
        mgs, 04 Mar 1998: - toptitle is now default, changed keyword to
                    NO_TOPTITLE ; eliminated search for '!' or '%'
        mgs, 10 Mar 1998: - rewritten again, now with named structure
                    returned as DATAINFO. Skipping of data blocks
                    drastically improved by setting the file pointer
                    instead of reading the lines.
        mgs, 16 May 1998: - removed DATATYPE3DP function, set type tag to -1
                  - added EXTRA_SPACE option for GISS_II_PRIME output and
                    LINELENGTH keyword for full flexibility
                  - now ignores time series ('TS...') data
        mgs, 13 Aug 1998: - format string now composed here, not in
                    read3dp_data
        mgs, 14 Aug 1998: VERSION 2.00 - major changes!
                  - now requires open file and uses ILUN parameter
                  - automatic EXTRA_SPACE detection
                  - fileinfo structure not created any more, and only
                    extended if present (chkstru)
                  - error messages as dialog box
                  - LINELENGTH keyword removed
        mgs, 15 Aug 1998: - now calls select_model and inserts model
                    information in fileinfo structure
                  - gamap_cmn.pro included for default model name
                  - had to change DEBUG keyword into PRINT
        mgs, 21 Sep 1998: - changed gamap.cmn to gamap_cmn.pro
        mgs, 26 Oct 1998: - now resets error state in no_dim
        mgs, 14 Jan 1998: - new lcount for line counting in error report
                  - linelength adjusted for working in Windows (CR/LF)
        bmy, 11 Feb 1999: VERSION 2.01
                  - Add window offsets (I0,J0,L0) to DATAINFO 
                  - save DATAINFO.TAU0 and DATAINFO.TAU1 as double precision
        bmy, 17 Feb 1999: VERSION 2.02
                  - changed to accommodate the FIRST field (instead of OFFSET)
                    of the DATAINFO structure, which contains
                    the I, J, L indices of the first grid box
        bmy, 01 Mar 1999: 
                  - bug fix!  NL needs to be a longword, so that
                    we can read 2 x 2.5 punch files correctly!! 
        mgs, 23 Mar 1999: 
                  - cleaned up reading of dimensions from label a little
        mgs, 27 May 1999: 
                  - new default number of records is 512 instead of 4096.
                  - bug fix: new records were never appended.
        mgs, 22 Jun 1999: 
                  - bug fix: "title" needed to be trimmed.
        bmy, 20 Jan 2000: FOR GAMAP VERSION 1.44
                  - !ERR is now replaced by !ERROR_STATE.CODE
                  - !ERR_STRING is now replaced by !ERROR_STATE.MSG
                  - I/O error trapping is now done by testing error
                    messages instead of testing for error numbers
                  - cosmetic changes, updated comments
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10

(See /n/home09/ryantosca/IDL/gamap2/internals/ctm_read3dp_header.pro)


CTM_READ_COARDS

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
        CTM_READ_COARDS

 PURPOSE:
        Reads data blocks from a COARDS-compliant netCDF file (such
        as created by routine BPCH2COARDS) into GAMAP.  CTM_READ_COARDS 
        is is an internal routine which is called by CTM_OPEN_FILE.

        NOTE: COARDS is a formatting standard for netCDF files which
        is widely used in both the atmospheric & climate communities.
        COARDS-compliant netCDF files can be read by GAMAP, GrADS and
        other plotting packages.
        
        See http://ferret.wrc.noaa.gov/noaa_coop/coop_cdf_profile.html
        for more information about the COARDS standard.

 CATEGORY:
        GAMAP Internals, Scientific Data Formats

 CALLING SEQUENCE:
        CTM_READ_COARDS, [, Keywords ]

 INPUTS:
        ILUN -> GAMAP file unit which will denote the netCDF file.

        FILENAME -> Name of the netCDF grid file to be read.
 
        FILEINFO -> Array of FILEINFO structures which will be
             returned to CTM_OPEN_FILE.  CTM_OPEN_FILE will 
             append FILEINFO to the GAMAP global common block.

        DATAINFO -> Array of DATAINFO structures (each element 
             specifies a GAMAP data block) which will be returned
             to CTM_OPEN_FILE.  CTM_OPEN_FILE will append FILEINFO 
             to the GAMAP global common block.        

 KEYWORD PARAMETERS:
        _EXTRA=e -> Picks up extra keywords

 OUTPUTS:
        None

 SUBROUTINES:
        Internal Subroutines:
        ====================================================
        CRC_Get_DimInfo        CRC_Get_IndexVars   
        CRC_Read_Global_Atts   CRC_Get_Tracer
        CRC_Get_Data           CRC_Save_Data

        External Subroutines Required:
        ====================================================
        CTM_GRID          (function)   CTM_TYPE (function)
        CTM_MAKE_DATAINFO (function)   STRRIGHT (function)
        STRREPL           (function)

 REQUIREMENTS:
        Requires routines from both GAMAP and TOOLS packages.

 NOTES:
        (1) Assumes that data blocks have the following dimensions:
            (a) longitude, latitude, time  
            (b) longitude, latitude, levels, time

        (2) Assumes that times are given in GMT.

        (3) If information about each tracer in the COARDS-compliant
            netCDF file is stored in the GAMAP "tracerinfo.dat" file, 
            then CTM_READ_COARDS will be able to read the file without 
            having to ask the user to supply a GAMAP category and
            tracer name.  
       
 EXAMPLE:
        ILUN     = 21
        FILENAME = 'coards.20010101.nc'
        CTM_READ_COARDS, ILUN, FILENAME, FILEINFO, DATAINFO

             ; Reads data from the COARDS-compliant netCDF file 
             ; coards.20010101.nc and stores it the FILEINFO and 
             ; DATAINFO arrays of structures.  If you are calling 
             ; CTM_READ_COARDS from CTM_OPEN_FILE, then CTM_OPEN_FILE 
             ; will append FILEINFO and DATAINFO to the GAMAP global
             ; common block.

 MODIFICATION HISTORY:
        bmy, 21 Mar 2005: GAMAP VERSION 2.03
        bmy, 21 Jul 2005: GAMAP VERSION 2.04
                          - bug fix in CRC_SAVE_DATA
        bmy, 06 Mar 2006: GAMAP VERSION 2.05
                          - minor bug fix in CRC_READ_GLOBAL_ATTS
                          - bug fix in CRC_SAVE_DATA: add a fake 4th
                            dim to DATA array if needed
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10
        bmy, 16 Sep 2008: GAMAP VERSION 2.13
                          - Convert some global attributes to number
                            types in case attributes were initially
                            saved to the netCDF file as strings
        phs, 15 Sep 2009: - Added check on reading tracerinfo.dat
                          - Convert some tracer names created by
                            BPCH2COARDS to their original value.
        bmy, 14 Dec 2011: GAMAP VERSION 2.16
                          - Updated to read the GAMAP category value
                            from a netCDF variable attribute (if present)
        bmy, 19 Dec 2011: - Generalized to handle several different
                            vertical levels
        bmy, 21 Dec 2011: - Now will interpret netCDF attributes
                            "begin_date" and "begin_time" in the same
                            way as "start_date" and "start_time"
        bmy, 22 Dec 2011: - Now compute FIRST (nested datablock offsets)
                            properly for nested grids.  For now assume
                            that the data will always start on the first
                            vertical level.
                          - Bug fix: test for Latrev gt 0 to avoid
                            INADVERTENTLY reversing latitudes
        bmy, 03 Jan 2012: - Skip over Ap and Bp index arrays
                          - Now use better error checks for
                            the time and vertical level dimensions
                            for each tracer in the netCDF file.
        bmy, 05 Jan 2012: - Now interpret DELTA_TIME attribute
                            correctly when specified in hhmmss format.
        bmy, 10 Jan 2012: - Fix to interpret data blocks with multiple 
                            vertical dimensions in the same file 
        bmy, 13 Jan 2012: - When the time dimension in the netCDF
                            file is 1 (esp. when time is an UNLIMITED
                            variable, we need to add a fake dimension
                            of 1 back onto the data block to avoid
                            crashes.  This is a quirk in how the IDL
                            NCDF_VARGET function works.
        bmy, 23 Jan 2017: GAMAP VERSION 2.19
                          - Add modifications to read netCDF restart files

(See /n/home09/ryantosca/IDL/gamap2/internals/ctm_read_coards.pro)


CTM_READ_DATA

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
        CTM_READ_DATA

 PURPOSE:
        read in one data block from a global model punch file output
        (ASCII or binary)

 CATEGORY:
        GAMAP Internals

 CALLING SEQUENCE:
        CTM_READ_DATA,data,datainfo
        or:
        CTM_READ_DATA,data,ilun,filepos,xsize,ysize[,zsize,keywords]

 INPUTS:
        DATAINFO -> a datainfo structure as retrieved from
             CTM_OPEN_FILE. This is the easiest way to read 3D
             model output. Alternatively, the individual parameters
             can be specified as follows.
             
        ILUN  -> logical file unit of input file (must be opened before)
        FILEPOS -> a long word containing the start position of the data
             block to be read (normally retrieved by CTM_OPEN_FILE)
        XSIZE -> 1st dimension of the data array
        YSIZE -> 2nd dimension of the data array
        ZSIZE -> optional 3rd dimension of the data array

 KEYWORD PARAMETERS:
        Note: These keywords are ineffective when parameters are passed
        via the DATAINFO structure!

        SCALE -> apply scaling factor to data (default = 1.0)

        FORMAT -> string with format identifier for data block
             Default is '(12f6.2)'. Use '(8e10.3)' for BUDGETS output and
             '(12(f6.2,1x))' for "extra_space" output. Format='BINARY'
             indicates a binary file with REAL*4 data. (As long as the
             dimensions are specified correctly ANY binary file can
             be read this way, i.e. there is no need for additional 
             routines to read in e.g. gridded emission data files)

        RESULT -> will return 1 if successful, 0 otherwise

 OUTPUTS:
        DATA  -> a float array containing the block of data which is 
             either a 2D or a 3D array.

 SUBROUTINES:

 REQUIREMENTS:
        file must have been opened and file positions of the data block
        must be known (see CTM_OPEN_FILE)

 NOTES:
        The data array is *not* added to the datainfo structure! 

 EXAMPLE:
        ; Open a punch file interactively
        CTM_OPEN_FILE,'',fileinfo,datainfo

        ; Test if successful
        IF (not chkstru(datainfo)) then return

        ; Read in data of first data block
        CTM_READ_DATA,data,datainfo[0]

        ; This is equivalent to:
        CTM_READ_DATA,data,fileinfo.ilun,datainfo[0].filepos, $
             datainfo[0].dim[0],datainfo[0].dim[1],datainfo[0].dim[2], $
             scale=datainfo[0].scale,format=datainfo[0].format

 MODIFICATION HISTORY:
        mgs, 13 Aug 1998: VERSION 1.00 (from CTM_READ3DP_DATA)
                          - replaced EFORMAT keyword by more flexible 
                            FORMAT keyword (involves changes in 
                            CTM_READ3DP_HEADER and CREATE_3DHSTRU)
        mgs, 17 Aug 1998: VERSION 2.00
                          - now possible to pass DATAINFO structure
                          - made it necessary to place DATA argument 
                            as first parameter
        mgs, 19 Aug 1998: - added RESULT keyword
        mgs, 26 Oct 1998: - changed print statements to message
                          - user is now prompted when dimensions 
                            are not given
        bmy, 07 Apr 2000: - Added DAO keyword for reading in DAO met fields
        bmy, 11 Apr 2001: - now uses DATA = TEMPORARY( DATA ) * SCALE[0]
                            in order to prevent excess memory usage
        bmy, 19 Nov 2003: GAMAP VERSION 2.01
                          - Removed GMAO keyword, we now use the
                            FORMAT string to test for GMAO data files
  phs & bmy, 13 Jul 2007: GAMAP VERSION 2.10
                          - Modified for 4-D data blocks

(See /n/home09/ryantosca/IDL/gamap2/internals/ctm_read_data.pro)


CTM_READ_EOSGR

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
        CTM_READ_EOSGR

 PURPOSE:
        Reads data blocks from a HDF-EOS Grid file into GAMAP.
        (This is an internal routine which is called by CTM_OPEN_FILE.)
        
 CATEGORY:
        GAMAP Internals, Scientific Data Formats

 CALLING SEQUENCE:
        CTM_READ_EOSGR, ILUN, FILENAME, FILEINFO, DATAINFO, [, Keywords ]

 INPUTS:
        ILUN -> GAMAP file unit which will denote the HDF-EOS file.

        FILENAME -> Name of the HDF-EOS grid file to be read.
 
        FILEINFO -> Array of FILEINFO structures which will be
             returned to CTM_OPEN_FILE.  CTM_OPEN_FILE will 
             append FILEINFO to the GAMAP global common block.

        DATAINFO -> Array of DATAINFO structures (each element 
             specifies a GAMAP data block) which will be returned
             to CTM_OPEN_FILE.  CTM_OPEN_FILE will append FILEINFO 
             to the GAMAP global common block.
      
 KEYWORD PARAMETERS:
        _EXTRA=e -> Picks up any extra keywords

 OUTPUTS:
        None

 SUBROUTINES:
        Internal Subroutines:
        =====================================================
        CRE_Get_DimInfo   CRE_Get_TracerInfo   CRE_Save_Data

        External Subroutines Required:
        =====================================================
        CTM_GRID          (function)   CTM_TYPE (function)
        CTM_MAKE_DATAINFO (function)   STRRIGHT (function)

 REQUIREMENTS:
        Requires routines from both GAMAP and TOOLS packages.

 NOTES:
        (1) Currently is set up to read HDF-EOS files containing
            GMAO met data files.  You must have all possible met
            field names listed in your "tracerinfo.dat" file or 
            else you will get an "Invalid Selection" error.
                
 EXAMPLE:
        ILUN     = 21
        FILENAME = 'a_llk_03.tsyn2d_mis_x.t20030801'
        CTM_READ_EOSGR, ILUN, FILENAME, FILEINFO, DATAINFO

             ; Reads data from HDF-EOS file a_llk_03.tsyn2d_mis_x.t20030801
             ; and stores it the FILEINFO and DATAINFO arrays of
             ; structures.  If calling CTM_READ_GMI from CTM_OPEN_FILE,
             ; then CTM_OPEN_FILE will append FILEINFO and DATAINFO
             ; to the GAMAP common block.

 MODIFICATION HISTORY:
        bmy, 12 Nov 2003: GAMAP VERSION 2.01
                          - initial version
        bmy, 19 Feb 2004: GAMAP VERSION 2.01a
                          - added c402_rp_02 to the assim list
                          - bug fix: use DEFAULT keyword for SELECT_MODEL
        bmy, 09 Mar 2004: GAMAP VERSION 2.02
                          - now test for "GEOS3", "GEOS4" strings in
                            the file name to determine model type
                          - now undefine variables after use
                          - now make sure that data block begins at the
                            date line and has longitude values in the
                            range [-180,180] degrees.
                          - always ensure that L=1 is the surface level
        bmy, 25 Aug 2004: GAMAP VERSION 2.03
                          - Added c402_cer to the assim list
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10
                          - Remove reference to unused SORT_STRU
        bmy, 05 Dec 2007: GAMAP VERSION 2.12
                          - Modified for DAS.llk.asm files
        bmy, 01 Oct 2008: GAMAP VERSION 2.13
                          - Increase DI, DJ in CRE_GET_DIMINFO for
                            the 0.5 x 0.667 grid
                          - Also now test for GEOS-5 in the filename
                            in CRE_GET_DIMINFO
                          - Bug fix in CRE_SAVE_DATA: If there is
                            only one data time in the HDF-EOS file,
                            then add an extra dimension to THISDATA
                            so that the CASE statement will be
                            interpreted properly.

(See /n/home09/ryantosca/IDL/gamap2/internals/ctm_read_eosgr.pro)


CTM_READ_GMAO

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
        CTM_READ_GMAO

 PURPOSE:
        Reads GMAO I-6,(instantaneous 6h), A-6 (average 6h),
        or A-3 (average 3-h) met field files, and constructs
        a DATAINFO structure for each met field.

 CATEGORY:
        GAMAP Internals
 
 CALLING SEQUENCE:
        Result = CTM_READ_GMAO( Ilun, FileInfo, DataInfo [, Keywords ] )

 INPUTS:
        ILUN --> The name of the input file (or a file mask).
             FILENAME is passed to OPEN_FILE.  If FILENAME is a null 
             string or a file mask, then OPEN_FILE will open a
             pickfile dialog box.

        FILEINFO --> a (single) fileinfo structure containing information
             about the (open) file (see CREATE3DFSTRU). FILEINFO also
             contains information about the model which generated
             the output (see CTM_TYPE)

        DATAINFO --> a named variable that will contain an array of
             structures describing the file content (see
             CREATE3DHSTRU)

 KEYWORD PARAMETERS:
        PRINT  -> if activated, print all headers found in the file

 OUTPUTS:
        The function returns 1 if successful, and 0 otherwise. 

        FILEINFO --> toptitle and modelinfo tags will be set

        DATAINFO --> contains an array of named structures 
             (see CREATE3DHSTRU) with all relevant information
             from the punch file header and what is needed to find
             and load the data.

 SUBROUTINES:
        Internal Subroutines:
        ================================================
        CRG_GET_MODELINFO

        External Subroutines Required:
        ================================================
        CHKSTRU  (function)     CTM_GRID      (function)
        CTM_TYPE (function)     CREATE3DHSTRU (function)
        

 REQUIREMENTS:
        References routines from both GAMAP and TOOLS packages.

 NOTES:
        (1) You must also add additional met field names to your
        "tracerinfo.dat" file as is neccesary.  CTM_READ_GMAO looks
        up met fields stored under the GAMAP categories "GMAO-2D"
        and "GMAO-3D$".

        (2) GEOS-4 met field files have an 8-char ident string 
        of the format "G4 45 19", where:

           (a) "G4" means that it is a GEOS-4 met field file/
           (b) "45" is the resolution code (in this case 4x5).
           (c) "19" is the number of met fields stored w/in the file.

        CTM_READ_GMAO will now set the modeltype and resolution from
        the information in this ident string.  For older met field 
        types (e.g. GEOS-3) which do not have this ident string,
        CTM_READ_GMAO will determine the modeltype and resolution 
        from the filename and date.

 EXAMPLES:
        FileInfo = CREATE3DFSTRU()   ; not required !
        FName    = '/r/amalthea/N/scratch/bmy/960101.a3.4x5'
        OPEN_FILE, FName, Ilun, /F77_Unformatted   
        if ( Ilun gt 0 ) $
            then Result = CTM_READ_GMAO( Ilun, FileInfo, DataInfo )
        print,result

 MODIFICATION HISTORY:
        bmy, 16 May 2000: GAMAP VERSION 1.45
                          - adapted from original program "read_gmao"
        bmy, 12 Jun 2000: - declare XYMD and XHMS as integers for
                            GEOS-2 and GEOS-3 data
        bmy, 28 Jul 2000: GAMAP VERSION 1.46
                          - added GEOS-3 names to list of recognized fields
                          - deleted a couple of field names we don't use 
        bmy, 25 Sep 2000: - added new field: SLP (sea level pressure)
        bmy, 08 Dec 2000: GAMAP VERSION 1.47
                          - added new fields: TKE, RH, KH
        bmy, 07 Mar 2001: - added new fields: CLDTMP, TPW
        bmy, 25 Apr 2001: - added new fields: TAULOW, TAUMID, TAUHI
        bmy, 26 Jul 2001: GAMAP VERSION 1.48
                          - added new field: T2M
        bmy, 15 Aug 2001: - added new field: OPTDEPTH
        bmy, 06 Nov 2001: GAMAP VERSION 1.49
                          - added new field: DELP
                          - changed units from "mb" to "hPa"
        bmy, 29 Jan 2002: GAMAP VERSION 1.50
                          - added new field: GWET
                          - removed obsolete code from 11/6/01
        bmy, 01 May 2002: - added GWETTOP as synonym for GWET
                          - now assign correct units for fvDAS/GEOS-4
                            CLDMAS and DTRAIN fields: kg/m2/s
                          - now assign correct units for fvDAS/GEOS-4
                            PBL field: m (instead of hPa)
        bmy, 17 Jul 2002: GAMAP VERSION 1.51
                          - added PBLH, Z0M, Z0H fields for fvDAS/GEOS-4
        bmy, 16 Dec 2002: GAMAP VERSION 1.52:
                          - added new fvDAS fields: CMFDTR, CMFETR,
                            ZMDU, ZMED, ZMEU, ZMMD, ZMMU, HKETA, HKBETA
        bmy, 21 May 2003: GAMAP VERSION 1.53:
                          - added T, U, V as synonyms of TMPU, UWND, VWND
                          - added Q as a synonym of SPHU
                          - removed CMFDTR, CMFETR fields
                          - HKBETA is now #18; HKETA is now #19
                          - updated comments
                          - added EVAP field as tracer #28 
                          - TGROUND and T2M are now tracers #29, #30
                          - LAI is now tracer #31
                          - PARDF, PARDR are now tracers #32, 33
        bmy, 30 Jul 2003: - added TSKIN as a synonym for TGROUND
        bmy, 12 Dec 2003: GAMAP VERSION 2.01
                          - renamed to CTM_READ_GMAO to reflect the
                            change of name from "DAO" to "GMAO".
                          - GMAO binary files now have FILETYPE=104
                          - Rewrote so that we don't have to hardwire
                            met field names...it now gets the met
                            field names from "tracerinfo.dat"
                          - Now gets modeltype and resolution info
                            from GEOS-4 ident string 
                          - Added internal function CRG_GET_MODELINFO
                            to generate the MODELINFO structure based
                            on the filename and date. 
                          - Improved error output if we can't find
                            the tracer name
  bmy & phs, 03 Aug 2007: GAMAP VERSION 2.10
                          - Ident string value "56" now will specify
                            a grid with 0.5 x 0.666 degree resolution
                          - Ident string value "10" now will specify
                            a grid with 1.0 x 1.0 degree resolution
                          - Now don't reset ILUN for GEOS-5 files
                          - Now call EXTRACT_FILENAME in CRG_GET_MODELINFO
                            to get just the filename instead of the full
                            path name.
                          - Adjusted for GEOS-5 fields with LMX+1 levels
                          - Bug fix: set null strings if GMAO-2D and/or
                            GMAO-3D$ categories aren't found
                          - Bug fix: change "gt" to "ge" in IF statements
                            where NAME2D, NAME3D, etc. are defined.
                          - Now use IS_EDGED
                          - Added routine CRG_GET_HORZDIM to return NI,
                            NJ, NL, FIRST for global or nested grids.
        bmy, 06 Aug 2010: GAMAP VERSION 2.14
                          - Now check for MERRA grid.  This is
                            identical to GEOS-5, but retains the
                            "MERRA" name for clarity. 
        bmy, 11 Aug 2010: - Bug fix: define STRUC array of structures
                            with 1024 entries.  512 is not enough for
                            the hourly MERRA data.              
        bmy, 17 Aug 2010: - Bug fix: define STRUC array of structures
                            with 2048 entries.  1024 may not be
                            enough for the hourly MERRA data.              
  

(See /n/home09/ryantosca/IDL/gamap2/internals/ctm_read_gmao.pro)


CTM_READ_GMI

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
        CTM_READ_GMI

 PURPOSE:
        Reads data blocks from a GMI netCDF file into GAMAP.
        (This is an internal routine called from CTM_OPEN_FILE.)

 CATEGORY:
        GAMAP Internals

 CALLING SEQUENCE:
        CTM_READ_GMI, ILUN, FILENAME, FILEINFO, DATAINFO, [, Keywords ]

 INPUTS:
        ILUN -> GAMAP file unit which will denote the GMI netCDF file.

        FILENAME -> Name of the GMI netCDF grid file to be read.
 
        FILEINFO -> Array of FILEINFO structures which will be
             returned to CTM_OPEN_FILE.  CTM_OPEN_FILE will 
             append FILEINFO to the GAMAP global common block.

        DATAINFO -> Array of DATAINFO structures (each element 
             specifies a GAMAP data block) which will be returned
             to CTM_OPEN_FILE.  CTM_OPEN_FILE will append FILEINFO 
             to the GAMAP global common block.

 KEYWORD PARAMETERS:
        _EXTRA=e -> Picks up extra keywords
 
 OUTPUTS:
        None

 SUBROUTINES:
        Internal Subroutines:
        ===============================================
        CRG_Debug_Print   CRG_Get_Name   CRG_Get_Tau0       
        CRG_Get_Tracer    CRG_Get_Data   CRG_Save_Data

        External Subroutines Required:
        ===============================================
        CTM_GRID (function)   CTM_TYPE (function)
        NCDF_GET (function)   TVMAP

 REQUIREMENTS:
        Requires routines from both GAMAP and TOOLS packages.

 NOTES:
        (1) Currently is hardwired to reading in data blocks 
            from netCDF files created for the GMI comparison
            study.  It is difficult to create a general netCDF
            reader since there are many different ways to store
            data w/ in a netCDF file.

 EXAMPLE:
        ILUN     = 21
        FILENAME = 'gmit4_maccm3_year_CO.nc'
        CTM_READ_GMI, ILUN, FILENAME, FILEINFO, DATAINFO

             ; Reads data from the netCDF file gmit4_maccm3_year_CO.nc
             ; and stores it the FILEINFO and DATAINFO arrays of
             ; structures.  If calling CTM_READ_GMI from CTM_OPEN_FILE,
             ; then CTM_OPEN_FILE will append FILEINFO and DATAINFO
             ; to the GAMAP common block.
 
 MODIFICATION HISTORY:
        bmy, 05 Nov 2003: GAMAP VERSION 2.01
                          - initial version
        bmy, 13 Feb 2004: GAMAP VERSION 2.01a
                          - bug fix: now should get multiple months
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10

(See /n/home09/ryantosca/IDL/gamap2/internals/ctm_read_gmi.pro)


CTM_READ_MULTILEVEL

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
        CTM_READ_MULTILEVEL

 PURPOSE:
        Read all levels of a multilevel diagnostic (e.g. IJ-AVG-$)
        and return a 3D data block. The associated datainfo structure
        must be created before and passed into this routine.
        This is an internal procedure which should not be used
        directly.

 CATEGORY:
        GAMAP Internals

 CALLING SEQUENCE:
        CTM_READ_MULTILEVEL,data,datainfo, $
                   Use_DataInfo=Use_DataInfo, $
                   Use_FileInfo=Use_FileInfo, $
                   result=result

 INPUTS:
        DATAINFO -> The datainfo structure that is to hold the new 
             3D data block.

 KEYWORD PARAMETERS:
        USE_DATAINFO, USE_FILEINFO -> The array of Datainfo and Fileinfo
             stuctures to select from. Unlike the higher level routines,
             CTM_READ_MULTILEVEL does not provide default values for 
             these! 

        RESULT -> A named variable that will be 1 if successful, 
             0 otherwise.

 OUTPUTS:
        DATA -> The 3D data block composed of the individual levels
             from the ASCII punch file. 

 SUBROUTINES:
        External Subroutines Required:
        ===========================================
        EXPAND_CATEGORY     CTM_DIAGINFO
        CTM_DOSELECT_DATA   CTM_READ_DATA

 REQUIREMENTS:
        Requires routines from both GAMAP and TOOLS packages.

 NOTES:
        The dimensional information of the DATAINFO parameter is 
        adapted to the number of levels actually read from disk.

 EXAMPLE:
        See source code of CTM_RETRIEVE_DATA

 MODIFICATION HISTORY:
        mgs, 19 Aug 1998: VERSION 1.00
        mgs, 26 Oct 1998: - made more error tolerant: 
                            = if file ends within record, now returns 
                              what's there
                            = if no dimensions were read, 
                              assumes 72x46 and prints warning
                            = added status keyword
        mgs, 10 Nov 1998: VERSION 3.00
                          - major design change
        mgs, 28 Nov 1998: - hopefully fixed scaling bug now
        bmy, 19 Nov 2003: GAMAP VERSION 2.01
                          - Now get diagnostic spacing from CTM_DIAGINFO
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10

(See /n/home09/ryantosca/IDL/gamap2/internals/ctm_read_multilevel.pro)


CTM_READ_MULTITRACER

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
        CTM_READ_MULTITRACER

 PURPOSE:
        Read all entries of a 'multitracer' diagnostic (i.e.
        source type diagnostic) and return a 3D data block.
        The associated datainfo structure must be created before 
        and passed into this routine. This routien is meant for
        internal use in the CTM_GET_DATA routines.

 CATEGORY:
        GAMAP Internals

 CALLING SEQUENCE:
        CTM_READ_MULTITRACER,data,datainfo, $
                   Use_DataInfo=Use_DataInfo,  $
                   Use_FileInfo=Use_FileInfo,  $
                   result=result,debug=debug

 INPUTS:
        DATAINFO -> The datainfo structure that is to hold the new
             3D data block. 

 KEYWORD PARAMETERS:
        USE_DATAINFO, USE_FILEINFO -> The array of Datainfo and Fileinfo
             stuctures to select from. Unlike the higher level routines,
             CTM_READ_MULTILEVEL does not provide default values for
             these!

        RESULT -> A named variable that will be 1 if successful, 
             0 otherwise.

 OUTPUTS:
        DATA -> The 3D data block composed of the individual levels
             from the ASCII punch file.

 SUBROUTINES:

 REQUIREMENTS:
        Uses CTM_DOSELECT_DATA, CTM_READ_DATA

 NOTES:
        The dimensional information of the DATAINFO parameter is
        adapted to the number of levels actually read from disk.

 EXAMPLE:
        See source code of CTM_***

 MODIFICATION HISTORY:
        mgs, 19 Aug 1998: VERSION 1.00
        mgs, 26 Oct 1998: made more error tolerant:
             - if file ends within record, now returns what's there
             - if no dimensions were read, assumes 72x46 and prints warning
        mgs, 10 Nov 1998: VERSION 3.00
             - major design change
        mgs, 28 Nov 1998: 
             - hopefully fixed scaling bug now
  bmy & phs: 13 Jul 2007: GAMAP VERSION 2.10

(See /n/home09/ryantosca/IDL/gamap2/internals/ctm_read_multitracer.pro)


CTM_READ_NCDF

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 NAME:
        CTM_READ_NCDF

 PURPOSE:
        Reads data blocks from a netCDF file created by routine
        BPCH2NC or BPCH2GMI into GAMAP.  (This is an internal routine 
        which is called by CTM_OPEN_FILE.)

 CATEGORY:
        GAMAP Internals, Scientific Data Formats

 CALLING SEQUENCE:
        CTM_READ_NCDF, [, Keywords ]

 INPUTS:
        ILUN -> GAMAP file unit which will denote the netCDF file.

        FILENAME -> Name of the netCDF grid file to be read.
 
        FILEINFO -> Array of FILEINFO structures which will be
             returned to CTM_OPEN_FILE.  CTM_OPEN_FILE will 
             append FILEINFO to the GAMAP global common block.

        DATAINFO -> Array of DATAINFO structures (each element 
             specifies a GAMAP data block) which will be returned
             to CTM_OPEN_FILE.  CTM_OPEN_FILE will append FILEINFO 
             to the GAMAP global common block.        

 KEYWORD PARAMETERS:
        _EXTRA=e -> Picks up extra keywords

 OUTPUTS:
        None

 SUBROUTINES:
        Internal Subroutines:
        ====================================================
        CRN_Get_DimInfo       CRN_Get_Time   CRN_Get_Tracer     
        CRN_Read_Global_Atts  CRN_Get_Data   CRN_Save_Data

        External Subroutines Required:
        ====================================================
        CTM_GRID          (function)   CTM_TYPE (function)
        CTM_MAKE_DATAINFO (function)   STRRIGHT (function)

 REQUIREMENTS:
        Requires routines from both GAMAP and TOOLS packages.

 NOTES:
        (1) Currently assumes that the netCDF file was written
            by GAMAP routine BPCH2NC.

 EXAMPLE:
        ILUN     = 21
        FILENAME = 'geos.20010101.nc'
        CTM_READ_NCDF, ILUN, FILENAME, FILEINFO, DATAINFO

             ; Reads data from the netCDF file geos.20010101.nc
             ; and stores it the FILEINFO and DATAINFO arrays of
             ; structures.  If calling CTM_READ_GMI from CTM_OPEN_FILE,
             ; then CTM_OPEN_FILE will append FILEINFO and DATAINFO
             ; to the GAMAP common block.

 MODIFICATION HISTORY:
        bmy, 05 Nov 2003: GAMAP VERSION 2.01
                          - initial version
        bmy, 26 Mar 2004: GAMAP VERSION 2.02
                          - bug fix: now correctly separates "__"
                            in netCDF tracer names with STRPOS
        bmy, 28 Feb 2005: GAMAP VERSION 2.03
                          - bug fix: now also exclude ETAC from
                            being passed to CRN_GET_TRACER
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10
                          - Modified to read files from BPCH2GMI
        bmy, 19 Dec 2007: GAMAP VERSION 2.12
                          - Now also skip ETAE, SIGE arrays
                          - Also don't add any vertical info to 
                            the GRIDINFO structure if NLAYERS=1
        bmy, 24 Jan 2011: GAMAP VERSION 2.15
                          - Now skip over Ap and Bp index fields
                            in the netCDF file
        bmy, 14 Dec 2011: GAMAP VERSION 2.16
                          - Now also check to see if the GAMAP
                            category string is passed via the netCDF
                            "gamap_category" attribute

(See /n/home09/ryantosca/IDL/gamap2/internals/ctm_read_ncdf.pro)


CTM_READ_PLANEFLIGHT

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
        CTM_READ_PLANEFLIGHT

 PURPOSE:
        Reads GEOS-CHEM plane flight diagnostic (ND40) data.  

 CATEGORY:
        GAMAP Utilities, GAMAP Data Manipulation

 CALLING SEQUENCE:
        RESULT = CTM_READ_PLANEFLIGHT( FILENAME )

 INPUTS:
        FILENAME -> Name of the file containing data from the GEOS-CHEM
             plane following diagnostic ND40.  If FILENAME is omitted,
             then a dialog box will prompt the user to supply a file name.

 KEYWORD PARAMETERS:
        None

 OUTPUTS:
        RESULT -> Array of structures containing data from read from
             the input file.  Each different plane type will have 
             a structure in RESULT containing the following tags:
 
             NPOINTS  : Number of points read from the file 
             NVARS    : Number of variables read from the file
             PLATFORM : Name of plane type (e.g. DC8, P3B, FALCON)
             DATE     : Array w/ YYYYMMDD  at each flight point [GMT date]
             TIME     : Array w  HHMM      at each flight point [GMT time]
             LAT      : Array w/ latitude  at each flight point [degrees ]
             LON      : Array w/ longitude at each flight point [degrees ]   
             PRESS    : Array w/ pressure  at each flight point [hPa     ]
             VARNAMES : Array w/ names of each variable 
             DATA     : Array w/ data for each variable

 SUBROUTINES:

        External Subroutines Required:
        ==========================================
        OPEN_FILE   STRBREAK (function)  UNDEFINE

 REQUIREMENTS:
        None

 NOTES:
        We read the data into arrays first, and then save the arrays
        into an IDL structure.  If you read the data into an array of
        structures, this executes much more slowly.  Also arrays of
        structures seem to suck up an inordinate amount of memory.

 EXAMPLES:
        PLANEINFO = CTM_READ_PLANEFLIGHT( 'plane.log.20040601' )
             ; Reads data from file into the PLANEINFO structure

        DC8 = WHERE( PLANEINFO[*].PLATFORM eq 'DC801' )
             ; Look for DC8 data

        PRINT, PLANEINFO[DC8].LAT[*]
        PRINT, PLANEINFO[DC8].LON[*]
             ; Prints latitudes and longitudes of DC8 to the screen

        IND = WHERE( PLANEINFO[DC8].VARNAMES eq 'TRA_004' )
        CO  = PLANEINFO[DC8].DATA[ *, IND ]
             ; Extracts CO (tracer #4 in a GEOS-CHEM fullchem
             ; simulation) to an array

        IND  = WHERE( PLANEINFO[DC8].VARNAMES eq 'GMAO_UWND' )
        UWND = PLANEINFO[DC8].DATA[ *, IND ]
             ; Extracts U-wind information to an array 

 MODIFICATION HISTORY:
        bmy, 23 Mar 2005: GAMAP VERSION 2.03
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10

(See /n/home09/ryantosca/IDL/gamap2/gamap_util/ctm_read_planeflight.pro)


CTM_REGRIDH

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
        CTM_REGRIDH

 PURPOSE:
        Regrids data horizontally from one CTM grid to another, 
        for both cases:

           (1) fine grid    -->  coarse grid  OR
           (2) coarse grid  -->  fine grid

 CATEGORY:
        Regridding

 CALLING SEQUENCE:
        NEWDATA = CTM_REGRIDH( DATA, OLDGRID, NEWGRID [ , Keywords ] )

 INPUTS:
        DATA -> a 2-D or 3-D data field to be regridded.  DATA can be
             either in single-precision or double-precision.  

        OLDGRID, NEWGRID -> GRIDINFO structures (use "ctm_grid.pro" 
             to create one) defining the old and new grids.

 KEYWORD PARAMETERS:
        /DOUBLE -> If set, will return NEWDATA as a double-precision
             array.  Default is to return NEWDATA as a floating-point
             single-precision array.

        /PER_UNIT_AREA -> Set this switch if the quantity you want to
             regrid is per unit area or per unit volume (i.e. molec/cm2, 
             molec/cm3, kg/m2, etc.).  CTM_REGRIDH will multiply by
             the input grid's surface areas, so as to convert it to
             an area-independent quantity for regridding.  After the 
             regridding, CTM_REGRIDH will then divide the quantity
             by the surface areas on the new grid.  

        /USE_SAVED_WEIGHTS -> If set, will use the mapping weights
             saved by a prior call to CTM_REGRIDH.  This is useful
             if you are regridding 3-D data, thus CTM_REGRIDH can be
             told only to compute the mapping weights for the first
             level, thus saving processing time.

        /VERBOSE -> If set, will echo informational messages to the
             screen during the regridding process.  Totals on both
             old and new grids will also be printed.

        WFILE -> Name of the file with pre-saved mapping weights from
             the old grid to the new grid (created by CTM_GETWEIGHT).
             If WFILE is not specified, then CTM_REGRIDH will compute 
             the mapping weights on the fly.  These weights will be
             returned to the calling program via the WEIGHT keyword
             for use on subsequent calls to CTM_REGRIDH.  

 OUTPUTS:
        NEWDATA -> a 2-D or 3-D array containing the regridded data.

 SUBROUTINES:
        Internal Subroutines Included:
        =================================================
        CRH_GETWEIGHT 

        External Subroutines Required:
        =================================================
        CHKSTRU  (function)   CTM_BOXSIZE (function)   
        CTM_GETWEIGHT         UNDEFINE
       
 REQUIREMENTS:
        References routines from the GAMAP and TOOLS packages.

 NOTES:
        (1) CTM_REGRIDH now supersedes CTM_REGRID.  The old
            CTM_REGRID program worked fine, but could only 
            go from fine grids to coarse grids.

        (2) Assumes that you are passing globally-sized arrays.
            If you have less than global-sized data, then you 
            must add that data to a globally sized array, and
            then call CTM_REGRIDH.    

 EXAMPLE:
        (1)

        ; Define old grid
        OLDTYPE    = CTM_TYPE( 'GENERIC',    RES=[1,1], $
                                HALFPOLAR=0, CENTER180=0 )
        OLDGRID    = CTM_GRID( OLDTYPE )

        ; Define new grid
        NEWTYPE    = CTM_TYPE( 'GEOS_STRAT', RES=4 )
        NEWGRID    = CTM_GRID( NEWTYPE )

        ; Regrid data
        NEWDATA = CTM_REGRIDH( DATA, OLDGRID, NEWGRID, $
                               /PER_UNIT_AREA, /VERBOSE )

             ; Regrids a quantity such as fossil fuel emissions 
             ; in [molec/cm2/s] from the generic 1 x 1 emissions
             ; grid to GEOS-STRAT 4 x 5 resolution.  Message info 
             ; will be echoed to the screen during the regridding.
             ; The mapping weights from OLDGRID to NEWGRID will
             ; be computed by CTM_REGRIDH and stored internally
             ; for possible future use.  

        (2)

        ; Define old grid
        OLDTYPE  = CTM_TYPE( 'GEOS_STRAT', RES=2 )
        OLDGRID  = CTM_GRID( OLDTYPE )

        ; Define new grid
        NEWTYPE  = CTM_TYPE( 'GEOS_STRAT', RES=4 )
        NEWGRID  = CTM_GRID( NEWTYPE )

        ; Regrid first data array, read mapping weights from disk
        NEWDATA1 = CTM_REGRIDH( DATA1, OLDGRID, NEWGRID, $
                                WFILE='weights_generic1x1_geos4x5.dat' )

        ; Regrid second data array, use weights from prior call
        NEWDATA2 = CTM_REGRIDH( DATA2, OLDGRID, NEWGRID, $
                               /USE_SAVED_WEIGHTS )

             ; Regrids quantities such as air mass in [kg] from
             ; 2 x 2.5 resolution to 4 x 5 resolution for the
             ; GEOS-STRAT grid.  Since WFILE is specified,
             ; will read the mapping weights between OLDGRID and 
             ; from a file on disk instead of having to compute
             ; them online.  These mapping weights will then be
             ; saved internally for possible future use.
             ;
             ; Note that you can specify that you want to use the
             ; pre-saved with the /USE_SAVED_WEIGHTS flag.  This 
             ; prevents CTM_REGRIDH from having to re-read the 
             ; mapping weights all over again -- a real timesaver.

 MODIFICATION HISTORY:
        bmy, 13 Feb 2002: GAMAP VERSION 1.50
                          - adapted from CTM_REGRID plus 
                            other various existing codes
        bmy, 16 Jan 2003: GAMAP VERSION 1.52
                          - fixed a small bug which prevented flagging
                            coarse --> fine regridding when going from
                            1 x 1.25 to 1 x 1
        phs, 24 Oct 2005: GAMAP VERSION 2.05
                          - Fix the Coarse-to-Fine case. Works as
                            expected for both PER_UNIT_AREA=1 and =0.
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10
     jintai, 14 Apr 2010: GAMAP VERSION 2.14
                          - Added fix for NaN's

(See /n/home09/ryantosca/IDL/gamap2/regridding/ctm_regridh.pro)


CTM_RESEXT

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 NAME:
        CTM_RESEXT

 PURPOSE:
        Returns the proper filename extension for CTM resolution.

 CATEGORY:
        GAMAP Utilities, GAMAP Models & Grids

 CALLING SEQUENCE:
        RESULT = CTM_RESEXT( MODELINFO )

 INPUTS:
        MODELINFO -> a MODELINFO structure (output from function
             CTM_TYPE) desribing the desired CTM model.

 KEYWORD PARAMETERS:
        None

 OUTPUTS:
        Returns a string containing the model resolution.
        (e.g. '05x05', '1x1', '2x25', '4x5', '8x10' etc.)

 SUBROUTINES:
        External Subroutines Required:
        ==============================
        CHKSTRU (function)

 REQUIREMENTS:
        None

 NOTES:
        (1) Add more grid resolutions as is necessary.

 EXAMPLE:
        MODELINFO = CTM_TYPE( 'GEOS4' )
        PRINT, CTM_NAMEXT( MODELINFO )
             4x5

             ; Returns filename extension for the 
             ; 4x5 GEOS-4 model grid

 MODIFICATION HISTORY:
        bmy, 30 Jun 2000: GAMAP VERSION 1.46
        bmy, 08 Aug 2000: - Added string for 0.5 x 0.5
        bmy, 08 Feb 2006: GAMAP VERSION 2.04
                          - Added strings for 1.0 x 1.25 and 
                            0.5 x 0.625
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10
                          - added string for 0.5 x 0.667
        bmy, 09 Feb 2012: GAMAP VERSION 2.10
                          - Added string for 0.25 x 0.3125

(See /n/home09/ryantosca/IDL/gamap2/gamap_util/ctm_resext.pro)


CTM_RESTART_O3

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
        CTM_RESTART_O3

 PURPOSE:
        Merges single-tracer Ox data into a full-chemistry
        CTM restart file.

 CATEGORY:
        GAMAP Utilities

 CALLING SEQUENCE:
        CTM_RESTART_O3 [, BATCHFILE [, Keywords ] ]

 INPUTS:
        BATCHFILE (optional) -> Name of the input file containing
             the names of the full chemistry restart file, the
             single tracer O3 file, the annual mean tropopause file,
             and the output file.  If BATCHFILE is omitted, then the
             user will be prompted to make a selection via a dialog box.

 KEYWORD PARAMETERS:
        /STRAT_ONLY -> Set this keyword to only merge the stratospheric
             Ox into the full chemistry restart file.  Stratospheric 
             levels are determined by reading in the annual mean 
             tropopause file (as specified in BATCHFILE).  Default is
             to merge all levels into the full chemistry restart file.

 OUTPUTS:
        Will write merged data to an output file whose name is
        specified in BATCHFILE.

 SUBROUTINES:
        External subroutines required:
        ------------------------------------------------------
        CTM_GRID     (function)  CTM_GET_DATABLOCK (function)
        CTM_GET_DATA             OPEN_FILE
        STR2BYTE     (function)

 REQUIREMENTS:
        None

 NOTES:
        CTM_RESTART_O3 is currently only applicable to the GEOS-CTM,
        since this is the only model that can run single tracer Ox.

        A Sample BATCHFILE is given below.  There must be 3 header 
        lines before the first file name:

CTM_RESTART_O3.DAT -- defines filenames to read in for merging single 
                      tracer Ox data into a full chem restart file
=============================================================================
Full Chem File : /r/amalthea/N/scratch/bmy/run_3.2/gctm.trc.941001
Ox Run File    : /r/amalthea/N/scratch/bmy/run_o3_3.2/gctm.trc.941001
T-Pause File   : /r/amalthea/Li/data/ctm/GEOS_4x5/ann_mean_trop.geos1.4x5
Output File    : /scratch/bmy/gctm.trc.941001.new
=============================================================================

 EXAMPLE:
        CTM_RESTART_O3, 'filenames.dat', /STRAT_ONLY
             
             ; Will merge stratospheric single tracer Ox into the 
             ; full chemistry restart file.  Input and output file
             ; names are given in "filenames.dat".

 MODIFICATION HISTORY:
        bmy, 17 Feb 2000: VERSION 1.45
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10

(See /n/home09/ryantosca/IDL/gamap2/gamap_util/ctm_restart_o3.pro)


CTM_RETRIEVE_DATA

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 NAME:
        CTM_RETRIEVE_DATA

 PURPOSE:
        Read one "compound" data block from disk. The datainfo
        parameter must contain only one entry, and it must have
        status=0. The data pointer is assumed to be NULL.
        If requested data block is a multilevel or multitracer 
        diagnostics, the routine will search all individual data 
        records that belong to that block and loop over them
        (this is actually done in ctm_read_multilevel and 
        ctm_read_multitracer).

 CATEGORY:
        GAMAP Internals

 CALLING SEQUENCE:
        CTM_RETRIEVE_DATA,DataInfo,DiagStru,  $
                  Use_DataInfo=Use_DataInfo,  $
                  Use_FileInfo=Use_FileInfo,  $
                  result=result

 INPUTS:
        DataInfo -> DataInfo structure that is to hold the data.
            Normally, this is either created in CTM_GET_DATA for
            multilevel or multitracer diagnostics, or it is created
            upon parsing the header information (ctm_read3d?_header).

        DIAGSTRU -> A (single) diagnostic structure containing
            information what to load (see CTM_DIAGINFO)

 KEYWORD PARAMETERS:
        USE_DATAINFO, USE_FILEINFO -> The array of Datainfo and Fileinfo
             stuctures to select from. Unlike the higher level routines,
             CTM_READ_MULTILEVEL does not provide default values for
             these!

        RESULT -> A named variable that will be 1 if successful,
             0 otherwise.

 OUTPUTS:
        The DATAINFO structure will contain the correct dimensional
        information, the status will be set to 1, and the data pointer
        points to a 2D or 3D data array. (if reading was successful)

 SUBROUTINES:

 REQUIREMENTS:
        Uses CTM_DOSELECT_DATA, CTM_READ_MULTILEVEL, 
             CTM_READ_MULTITRACER, CTM_READ_DATA,
             gamap_cmn.pro

 NOTES:
        This routine is meant for internal use from CTM_GET_DATA.

 EXAMPLE:

 MODIFICATION HISTORY:
        mgs, 19 Aug 1998: VERSION 1.00
        mgs, 21 Sep 1998: - changed gamap.cmn to gamap_cmn.pro
        mgs, 22 Oct 1998: - scale factor set to 1 after unit scaling
                            is applied for multi...
                          - tracername and unit setting now also done
                            for non-multi fields
        mgs, 26 Oct 1998: - added status keyword. If used (0,1,or 2)
                            no data will be read but datainfo record 
                            will be prepared as usual.
        mgs, 04 Nov 1998: - bug fix for reading of 2D arrays. Now return
                            correct (offset) tracer number
        mgs, 10 Nov 1998: VERSION 3.00
                          - major design change 
        mgs, 28 Nov 1998: - hopefully fixed scaling bug now!
        bmy, 07 Apr 2000: - now can read DAO met field files
        bmy, 21 Nov 2003: GAMAP VERSION 2.01
                          - Removed GMAO keyword in call to
                            CTM_READ_DATA
        bmy, 23 Aug 2004: GAMAP VERSION 2.03 
                          - Now account for single-point data blocks
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10

(See /n/home09/ryantosca/IDL/gamap2/internals/ctm_retrieve_data.pro)


CTM_SELECT_DATA (FUNCTION)

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 NAME:
        CTM_SELECT_DATA (function)

 PURPOSE:
        Provide a user-friendly function to extract data
        from a DATAINFO structure. The function returns an 
        index to the given DATAINFO structure which points
        to all recored that fulfill the specified conditions.

 CATEGORY:
        GAMAP Internals, GAMAP Data Manipulation

 CALLING SEQUENCE:
        index = CTM_SELECT_DATA(DIAGN[,DATAINFO,keywords])

 INPUTS:
        DIAGN -> A diagnostic number or category name. Only one
            diagnostic can be extracted at the same time. Complete
            information about the requested diagnostic is returned 
            via the DIAGSTRU keyword. (see also CTM_DIAGINFO)

        DATAINFO -> An [optional] subset of the global DataInfo
            structure. As default, CTM_SELECT_DATA operates on
            the global DATAINFO structure (see gamap_cmn.pro) scanning
            all files that have been opened.

 KEYWORD PARAMETERS:
        ILUN -> A logical unit value or an array of logical unit
            values. Only recored from these files will be returned.
            Default is to use all files.
            A link between logical unit numbers and filenames can be
            made through the (global) FileInfo structure (see gamap_cmn.pro)

        TRACER -> A tracer number or an array of tracer numbers to
            restrict the selection of data records. Default is to
            return information about all tracers. 
            Tracer numbers less than 100 are automatically expanded
            to include the offset of certain diagnostics (see
            CTM_DIAGINFO and CTM_DOSELECT_DATA).

        TAU -> A time value (tau0 !) or an array of time values
            to restrict the selection of data records. Default is to
            return information about all time steps. (see also example)

        LEVELRANGE -> A 1 or 2 element vector with a level index or 
            a range of level indices for multilevel diagnostics
            (e.g. 'IJ-AVG$'). As default, information is returned
            about full 3D data blocks only. See also 
            EXPAND keyword.

        /EXPAND -> If set, multilevel diagnostic fields are
            expanded to return the individual layers in addition to
            the complete 3D cube.
        
        DATA -> A named variable that will contain an array with
            pointers to the indexed data blocks. Note that some may
            be NIL pointers if the STATUS value is 0 or 2.

        COUNT -> A named variable that will return the number of
            data blocks found with the given selection criteria
 
        DIAGSTRU -> A named variable that will contain complete 
            information about the requested diagnostics (see
            CTM_DIAGINFO)

        STATUS -> Restricts the data selection to
            Data that has not been read  (STATUS = 0)
            Data that has been read      (STATUS = 1, default)
            All data blocks              (STATUS = 2)
            If STATUS is 1, all pointers returned in DATA are valid.

 OUTPUTS:
        The function returns an (long) integer array that contains
        index values to all the data blocks that match the selection 
        criteria. If no data is found, -1 is returned.

 SUBROUTINES:

 REQUIREMENTS:
        Uses CTM_DOSELECT_DATA, EXPAND_CATEGORY, gamap_cmn.pro,
             GAMAP_INIT, CTM_DIAGINFO

 NOTES:
        This function acts for the most part as a convenient user
        interface to CTM_DOSELECT_DATA which performs the actual
        selection process and contains only minimal error checking.
        For programming purposes, use CTM_DOSELECT_DATA when possible.

 EXAMPLE:
        ; open a CTM punch file
        CTM_OPEN_FILE

        ; Read diagnostic number 45 for all tracers and time steps
        CTM_READ_DATA,45

        ; Select data for tracer 1 and diagnostics 45 
        index = CTM_SELECT_DATA(45,tracer=1,data=pdata)

        ; De-reference the data pointer for the first record
        ; (usually the first timestep)
        if (index[0] ge 0) then data = (*pdata)[0] 

        ; find data for a specific time range
        DataInfo = (*pGlobalDataInfo)[index]
        taus = where(DataInfo.tau0 ge 77666L AND DataInfo.tau1 le 78888L)
        taus = DataInfo.tau0[taus]
        index = CTM_SELECT_DATA(45,DataInfo,tracer=1,tau=taus,data=pdata)
        

 MODIFICATION HISTORY:
        mgs, 19 Aug 1998: VERSION 1.00
        mgs, 21 Sep 1998: - changed gamap.cmn to gamap_cmn.pro
        mgs, 07 Oct 1998: - removed obsolete FILEINFO parameter
                          - changed NO_EXPAND to EXPAND
        bmy, 19 Nov 2003: GAMAP VERSION 2.01
                          - Now get spacing between diagnostic offsets
                            from CTM_DIAGINFO and pass to CTM_DOSELECT_DATA
                          - Now use the /NO_DELETE keyword in the
                            call to routine EXPAND_CATEGORY
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10

(See /n/home09/ryantosca/IDL/gamap2/internals/ctm_select_data.pro)


CTM_SUM

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 NAME:
        CTM_SUM

 PURPOSE:
        Calculate the sum of several CTM output data blocks
        and store them in a new datainfo structure as "derived 
        data".  The user can select data blocks by diagnostics,
        tracer, tau0, or logical unit of the source file.  With 
        the AVERAGE keyword averages will be computed instead of
        totals.

 CATEGORY:
        GAMAP Utilities, GAMAP Data Manipulation

 CALLING SEQUENCE:
        CTM_SUM [, DIAGN ] [, Keywords ]

 INPUTS:
        DIAGN -> The diagnostic category name.  Default is 'IJ-AVG-$'

 KEYWORD PARAMETERS:
        TRACER -> Tracer number(s) to look for.

        TAU0 -> beginning of time step to look for. You can
            specify a date using function nymd2tau(YYMMDD,HHMMSS)

        ILUN -> If you want to restrict summation to datablocks from
            one particular file, set the ILUN keyword to the 
            respective logical unit number.  ILUN and FILENAME are
            mutually exclusive.  If you select FILENAME then ILUN 
            will be ignored.

        FILENAME -> Instead of ILUN you may pass the name of a
            CTM data file containing data blocks to be summed.
            FILENAME and ILUN are mutually exclusive.  If you 
            select FILENAME then ILUN will be ignored.

        NEWTRACER -> Tracer number for the new tracer. Default is 
            to use the same number as the tracer in the first 
            selected data block.

        NEWTAU0 -> A new pair of values for the time stamp. Default 
            is to use the minimum tau0 and maximum tau1 from the 
            selected data blocks. If only one value is passed (tau0),
            then tau1 will be set to tau0+1.

        /AVERAGE -> set this keyword to compute a (simple) average
            instead of the total.

 OUTPUTS:
        This routne produces no output but stores a new datainfo 
        and fileinfo structure into the global arrays.

 SUBROUTINES:
        uses gamap_cmn, ctm_get_data, ctm_grid, and ctm_make_datainfo

 REQUIREMENTS:
        None

 NOTES:
        All data blocks must originate from compatible models.
        No test can be made whether an identical addition had been
        performed earlier. Hence, it is a good idea to test the
        existence of the "target" record before in order to avoid 
        duplicates.

 EXAMPLE:
        (1) 
        CTM_GET_DATA, DATAINFO, 'IJ-AVG-$', $
          TRACER=1, TAU0=NYMD2TAU( 940301L )

        IF (N_ELEMENTS(DATAINFO) EQ 0) THEN $
           CTM_SUM, 'IJ-AVG-$', TRACER=[1,2,3,4,5],  $
              TAU0=NYMD2TAU(940301L), NEWTRACER=1

           ; Add individual CH3I tracers for 03/01/1994 and 
           ; store them  as total CH3I concentration. 
           ; But first: test!

        (2)
        CTM_SUM,'IJ-AVG-$',$
           TRACER=2, FILENAME='ctm.bpch.ox', /AVERAGE 
        
           ; Compute annual averages from monthly means for Ox

 MODIFICATION HISTORY:
        mgs, 18 May 1999: VERSION 1.00
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10
                          - Added FILENAME keyword as an 
                            alternative to ILUN
                          - Updated comments, cosmetic changes
        phs, 18 Aug 2008: GAMAP VERSION 2.13
                          - Added experimental keyword DIMAVER to
                            average along any dimension of the
                            datablocks.

(See /n/home09/ryantosca/IDL/gamap2/gamap_util/ctm_sum.pro)


CTM_SUM_EMISSIONS

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
        CTM_SUM_EMISSIONS

 PURPOSE:
        Computes totals of emissions in Tg [or Tg C] for the
        following diagnostics: ND28, ND29, ND32, ND36, ND46, ND13, etc.

 CATEGORY:
        GAMAP Utilities, GAMAP Data Manipulation

 CALLING SEQUENCE:
        CTM_SUM_EMISSIONS, DIAGN [, Keywords ]

 INPUTS:
        DIAGN -> A diagnostic category name to restrict 
             the record selection (default is "ANTHSRCE").

 KEYWORD PARAMETERS:
        FILENAME -> Punch file (ASCII or Binary) from which to 
             read CTM emissions data.  If omitted, the user
             will be prompted to select a file via a dialog box.

        FORMAT -> To overwrite the default format to output the
             sum.

        TRACER -> The tracer number (or a 1-D array of tracer
             numbers) to compute emission totals for.

        /CUM_ONLY -> If this switch is set, SUM_EMISSIONS will
             only print out cumuluative totals (and skip individual
             totals for each data block).

        RESULT -> An array of structures (tag names: NAME, SUM, UNIT) 
             that returns, the name of each tracer, its cumulative
             total, and its unit to the calling program.
           
        /NO_SECONDS -> Set this switch if the data to be summed is
             independent of seconds (e.g. molec/cm2).  CTM_SUM_EMISSIONS
             will not multiply the data by the number of seconds in the 
             interval when converting to Tg.

        /KG -> Set this switch if the data to be summed is in kg
             instead of molec/cm2 or molec/cm2/s.  CTM_SUM_EMISSIONS
             will not multiply the data by the surface area of each
             grid box when converting to Tg.

        /TO_Mg -> Set this switch if you wish to display emissions
             totals in Mg instead of Tg.

        /TO_Gg -> Set this switch if you wish to display emissions
             totals in Gg instead of Tg.

        /SHORT -> Use a shorter output format to print totals.
             Default is to print out w/ the long output format.

        _EXTRA=e -> Picks up any extra keywords for CTM_GET_DATA
             or CTM_TRACERINFO.
 
 OUTPUTS:
        Prints totals in Tg or Tg C for each tracer to the screen

 SUBROUTINES:
        Internal Subroutines:
        ==================================================
        CSE_GetUnit (function)  CSE_GetAreaCm2 (function)
        CSE_GetInfo

        External Subroutines Required:
        ==================================================
        CTM_DIAGINFO            CTM_TRACERINFO
        CTM_GETDATA             CTM_BOXSIZE    (function)
        CTM_GRID    (function)  GAMAP_CMN
        TAU2YYMMDD  (function)  UNDEFINE

 REQUIREMENTS:
        None

 NOTES:
        (1) Most of the time there will be 1 data block per month,
            and the cumulative total will be a yearly total.

        (2) For NOx, a molecular weight of 14e-3 kg/mole will report
            results in Tg N.  A molecular weight of 46e-3 will report
            results in Tg NOx.  This can be changed in the file
            "tracerinfo.dat".

        (3) Should now be compatible with any model type and grid
            resolution.  As of 6/19/01, has only been tested using
            GEOS-CHEM diagnostic output.
   
 EXAMPLE:
        CTM_SUM_EMISSIONS, 'ANTHSRCE', $
                           FILENAME='ctm.bpch', TRACER=1, $
                           MODELNAME='GEOS1', RESOLUTION=4

             ; Will print emission totals for tracer #1 (NOx)
             ; for the ANTHSRCE (ND36) diagnostic, using data
             ; in file "ctm.bpch".  The data is from a GEOS-1 
             ; simulation on a 4x5 grid.

 MODIFICATION HISTORY:
        bmy, 26 Apr 2001: GAMAP VERSION 1.47
        bmy, 08 Jun 2001: - now uses correct tracer name, unit,
                            and molecular weight for CO--SRCE
        bmy, 19 Jun 2001: GAMAP VERSION 1.48
                          - added internal function CSE_GETUNIT
                            to return the proper unit string
                            ("Tg N", "Tg C", or "Tg").
                          - added internal function CSE_GETAREACM2
                            which gets the proper surface area
                            for each data block
                          - removed MODELNAME, RESOLUTION keywords
        bmy, 03 Jul 2001: - now can sum emissions from GENERIC grids
        bmy, 16 Aug 2001: - added /NO_SECONDS and /KG keywords
        bmy, 26 Sep 2001: GAMAP VERSION 1.49
                          - set XNUMOL = 1d-3 if /KG is set; this
                            will convert from g/cm2 to Tg correctly
        bmy, 21 Nov 2001: - added internal routine CSE_GETINFO
                          - now call CTM_EXTRACT to restrict the
                            totaling to any arbitrary lat/lon rectangle
        bmy, 10 Jan 2002: GAMAP VERSION 1.50
                          - Bug fix: Don't call CTM_EXTRACT if /KG is, 
                            set, since AREACM2 will be 1 in that case 
        bmy, 31 Jan 2002: - change output format from f10.4 to f12.4
        bmy, 10 Jun 2002: GAMAP VERSION 1.51
                          - added "kludge" for biomass burning files
                            if /NO_SECONDS is set; will use proper
                            mol wts & units for ACET, C3H8, C2H6
        bmy, 14 Jan 2003: GAMAP VERSION 1.52
                          - added another quick fix to get the unit strings
                            correct for sulfate and nitrogen tracers for ND13
        bmy, 19 Sep 2003: GAMAP VERSION 1.53
                          - now call PTR_FREE to free the pointer memory
        bmy, 19 Nov 2003: GAMAP VERSION 2.01
                          - now get the spacing between diagnostic
                            offsets from CTM_DIAGINFO
        bmy, 26 Mar 2004: GAMAP VERSION 2.02
                          - added FORMAT keyword
        bmy, 03 Dec 2004: GAMAP VERSION 2.03
                          - now pass /QUIET to CTM_GET DATA which
                            reduces a lot of printing to the screen
        bmy, 15 Mar 2005: - Added /TO_Gg and TO_Mg keywords, which
                            will print totals in either Gg or Mg
                            instead of the default unit of Tg
                          - Now pass _EXTRA=e to CTM_GET_DATA so that
                            we can restrict to a given time 
        bmy, 07 Apr 2006: GAMAP VERSION 2.05
                          - Added /SHORT keyword
        bmy, 29 Sep 2006: - Bug fix: now test for molec wt in kg/mole
                            in internal function CSE_GETUNIT
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10
        phs, 20 Mar 2008: GAMAP VERSION 2.12
                          - updated to work with nested grid
        mps, 23 Jan 2014: - Added case for NO to CSE_GetUnit for output from
                            GEOS-Chem v9-02 and higher versions
                          - Now report NO emissions in Tg N
                          - Now print unit 'Tg C' for BC/OC tracers

(See /n/home09/ryantosca/IDL/gamap2/gamap_util/ctm_sum_emissions.pro)


CTM_TRACERINFO

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
        CTM_TRACERINFO

 PURPOSE:
        Return information about one or all tracers for a given
        GEOS-Chem, GISS, or other CTM diagnostic.

 CATEGORY:
        GAMAP Utilities, GAMAP Data Manipulation, Structures

 CALLING SEQUENCE:
        CTM_TRACERINFO, TRACERN, TRACERSTRU [, Keywords ]

 INPUTS:
        TRACERN -> Tracer number or name for which to extract the 
            information. If TRACERN is numeric, it is interpreted as 
            an index to the FULLCHEM or SMALLCHEM tracernumber
            in the global model. If it is a string, it will be compared 
            to NAME then FULLNAME. TRACERN may contain more than one 
            element. To retrieve information about all tracers, use the
            /ALL_TRACERS keyword.

 KEYWORD PARAMETERS:
        /ALL_TRACERS -> Retrieve information about all tracers

        FILENAME --> Name of the tracerinfo file (default tracerinfo.dat)
            The file will be searched in the current directory first, then
            in the directory where ctm_tracerinfo.pro is located. If not found
            in either location, a standard data block is retrieved from this 
            file.

        /FORCE_READING -> Overwrite the contents of the common block

        FULLNAME -> Returns the (long) name of the requested tracer(s)

        INDEX -> Returns the CTM index of the requested tracer(s)

        MOLC -> Returns the carbon number of the requested tracer(s)
             (For hydrocarbons, this is the # moles C/mole tracer)

        MOLWT -> Returns the molecular weight (kg/mole) of the 
             requested tracer(s)

        NAME -> Returns the (short) name of the requested tracer(s)

        SCALE -> Standard scale factor for tracer

        UNIT -> Returns the standard unit of the requested tracer(s)
             (i.e. unit as supplied by CTM with standard scale factor 
             applied (e.g. ppbv instead of V/V))

        IS_EDGED -> Returns whether the given tracer is defined on
             level edges (IS_EDGED=1) or level centers (IS_EDGED=0).  

 OUTPUTS:
        TRACERSTRU -> returns a structure or structure array with the 
            following tags:
               NAME     : short name for tracer as used in the model
               FULLNAME : long name for tracer (may be used in titles)
               MWT      : molec. weight as kg N or kg C 
               INDEX    : tracer number
               MOLC     : carbon number for NMHC
               SCALE    : standard scale factor
               UNIT     : standard unit for tracer with scale factor applied
               IS_EDGED : Is tracer defined on level edges?

 SUBROUTINES:
        External Subroutines Required:
        ================================================
        FILE_EXIST (function)   ROUTINE_NAME (function)
        OPEN_FILE 
 
 REQUIREMENTS:
        None

 NOTES:
        At first call, the tracer information structure array is
        either read from file or retrieved from the
        DATA block at the end of this program. Thereafter, the information
        is stored in a common block where it is accessible in subsequent 
        calls.
        The newer tags MOLC, SCALE and UNIT are optional and defaulted
        to 1.0, 1.0, and 'UNDEFINED', resp.

 EXAMPLE:
        CTM_TRACERINFO, 2, RES
        PRINT, RES.NAME, RES.MWT, RES.INDEX
        ; prints        Ox    0.0480000     2

        CTM_TRACERINFO,'OX',RES
        PRINT, RES.NAME, RES.MWT, RES.INDEX
        ; prints identical results

        CTM_TRACERINFO,[1,3,5],NAME=NAME,MOLWT=MWT,MOLC=MOLC,/FORCE_READING
        PRINT, NAME, MWT, MOLC
        ; reads tracerinfo.dat file and prints 
        ; NOx PAN ALK4
        ; 0.0140000     0.121000    0.0120000
        ; 1.00000      1.00000      4.00000

 MODIFICATION HISTORY:
        mgs, 22 Apr 1998: VERSION 1.00
        mgs, 24 Apr 1998: - added NAME keyword
        bmy, 07 May 1998: - added MOLC structure field to store 
                            carbon number for NMHC
        mgs, 07 May 1998: VERSION 2.00
                          - substantially revised
        mgs, 08 May 1998: - added SCALE and UNIT tags, made them optional
        mgs, 28 May 1998: - bug fix with on_ioerror
        mgs, 09 Oct 1998: - bug fix for tracern=0, changed CALLING SEQ. entry
        mgs, 12 Nov 1998: - unit string now defaulted to 'UNDEFINED' 
        bmy, 03 Jan 2001: GAMAP VERSION 1.47
                          - skip tracer lines beginning with '#' character
        bmy, 17 Nov 2003: GAMAP VERSION 2.01
                          - Removed FULLI, SMALLI, they're obsolete
                          - now use INDEX for tracer number
                          - Now use new file format for "tracerinfo.dat"
                            which allows for 8-digit offset numbers
                          - No longer read defaults from internal datablock
                          - Updated comments 
        bmy, 06 Apr 2004: GAMAP VERSION 2.02
                          - added /VERBOSE keyword
        bmy, 09 Mar 2006: GAMAP VERSION 2.05
                          - Use "./tracerinfo.dat" as default in
                            order to facilitate reading in IDL 5.5-
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10
                          - Add IS_EDGED tag to TRACERINFO structure
                            to denote whether the tracer is defined
                            on level centers or level edges
                          - Implement temporary fix: call GET_IS_EDGED
                            to determine if a tracer is defined on
                            level edges.  There is probably a better way
                            to do this, work on that later.
                          - Now use FILE_WHICH to locate the
                            "tracerinfo.dat" file.
        phs, 30 Jun 2008: GAMAP VERSION 2.12
                          - bug fix to account for FILENAME
        phs, 22 Sep 2009: GAMAP VERSION 2.13
                          - added test on found/not found tracers

(See /n/home09/ryantosca/IDL/gamap2/gamap_util/ctm_tracerinfo.pro)


CTM_TYPE (FUNCTION)

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
        CTM_TYPE (function)

 PURPOSE:
        return basic parameters for various 3D models used in
        the Harvard tropospheric modeling group. This information
        should be sufficient for CTM_GRID to compute grid box edge
        and center vectors.

 CATEGORY:
        GAMAP Utilities, GAMAP Models & Grids, Structures

 CALLING SEQUENCE:
        MTYPE = CTM_TYPE( NAME [,FAMILY] [,KEYWORDS] )

 INPUTS:
        NAME -> a string containing the name of the model 
             (GISS_II, GISS_II_PRIME (or II_PRIME), GEOS1,
             GEOS_STRAT, FSU, MOPITT, or GENERIC (=DUMMY) )

        FAMILY -> model family (optional, will otherwise be extracted
             from NAME). Possible values: GISS or GEOS or FSU or ''

 KEYWORD PARAMETERS:
        NLAYERS -> number of vertical model layers. This number must
             correspond to the number of layers in the model output
             files and is used in conjunction with PTOP to convert
             sigma levels into pressure altitudes.
             [defaults: GEOS1=20, GEOS_STRAT=26, GISS=FSU=9 ]
     
        NTROP -> number of layers in the troposphere
             [defaults: GEOS1=14, GISS=7, FSU=12]

        PTOP -> pressure at model top
             [default 10 mbar except for GEOS_STRAT=0.1 mbar]
     
        PSURF -> average surface pressure (needed for conversion of
             sigma levels to altitudes) [default 984 mbar]
     
        RESOLUTION -> either a 2 element vector with [ DI, DJ ] or
             a scalar (DJxDI: 8=8x10, 4=4x5, 2=2x2.5, 1=1x1, 0.5=0.5x0.5)
             [default for all models is 4x5]
     
        HALFPOLAR = (1 | 0) -> indicates that polar boxes span 
             (half | same) latitude as all other boxes (DJ=const.)
             [default: 1]

        HYBRID = (1 | 0) -> indicates that the model is a 
             (sigma-pressure hybrid | pure sigma level ) model.
             [default: 0]

        /PRINT -> prints model parameters on the screen

 OUTPUTS:
        MTYPE -> A structure with the following tag names will be 
             returned:  NAME, FAMILY, NLAYERS, PTOP, PSURF, 
             RESOLUTION, HALFPOLAR, CENTER180, FULLCHEM.  If input 
             parameters are not correct, the function returns -1.

 SUBROUTINES:
        Internal Subroutines:
        =====================
        YES_NO_VAL (function)
        CHECK_RESOLUTION
        
 REQUIREMENTS:
        None

 NOTES:
        If you update this routine by adding additional models, make
        sure to update "select_model.pro" and "getsigma.pro" as well.

 EXAMPLES:
        (1)
        MTYPE = CTM_TYPE( 'GEOS1', RESOLUTION=2 )

             ; defines model parameters for the GEOS1 model 
             ; at 2 x 2.5 degree resolution.

        (2)
        MTYPE = CTM_TYPE( 'GISS_II' )
        MGRID = CTM_GRID( MTYPE )

             ; Use CTM_TYPE in conjunction with CTM_GRID to return
             ; the grid structure for the standard GISS_II model.

 MODIFICATION HISTORY:
        mgs, 02 Mar 1998: VERSION 1.00
        bmy, 07 Apr 1998: - Renamed to CTM_TYPE to keep
                            consistent with other CTM subroutines.
        mgs, 24 Apr 1998: - made structure named
        mgs, 19 May 1998: - added NTROP tag and keyword
        bmy, 19 Jun 1998: - now computes FSU model parameters
                          - GEOS_STRAT and GEOS-1 troposphere tops
                            are now computed separately
                          - added small bug fix for fullchem from mgs
        mgs, 14 Aug 1998: - added DUMMY name
        mgs, 15 Aug 1998: - added GEOS-1 as variant of GEOS1
        bmy, 21 Dec 1998: - changed NLAYERS for GEOS STRAT
        mgs, 22 Dec 1998: - small bug fix for GEOS family NTROP
        mgs, 22 Feb 1999: - added GENERIC (same as DUMMY) and allow
                            keyword settings for this name
        bmy, 23 Feb 1999: - Implemented FSU grid information
        mgs, 16 Mar 1999: VERSION 1.21 
                          - cosmetic changes
                          - changed function name yesno into yesno_val to
                            avoid conflicts.
                          - removed online tag because it's never
                            used
        bmy, 26 Jul 1999: VERSION 1.42
                          - added HYBRID keyword and tag name
                          - cosmetic changes 
        bmy, 15 Sep 1999: VERSION 1.43
                          - fixed bug for NTROP in GISS-II-PRIME, 9L
        bmy, 15 Oct 1999: VERSION 1.44
                          - now reset model names "GEOS-STRAT" and 
                            "GEOS-2" to "GEOS_STRAT" and "GEOS2"
        bmy, 03 Jan 2000: - added GEOS-2 model parameters
                          - changed NTROP to 16 for GEOS1
                          - changed NTROP to 22 for GEOS_STRAT
        bmy, 16 May 2000: VERSION 1.45
                          - reset NTROP to 19 for GEOS-STRAT    
                          - now use GEOS-2 47 layer grid    
        bmy, 01 Aug 2000: VERSION 1.46          
                          - added GEOS-3 48-layer grid
                          - added internal function CHECKRESOLUTION
                          - cosmetic changes, updated comments
        bmy, 26 Jun 2001: GAMAP VERSION 1.48
                          - fixed NTROP for GEOS-3 met fields
                          - for generic grids, return "GENERIC" in
                            uppercase as model name and family name
        bmy, 09 Oct 2001: GAMAP VERSION 1.49
                          - now accepts modelname "GEOS3_30L", and
                            returns a structure for 30-layer GEOS-3 grid
        bmy, 06 Nov 2001: - now recognizes "GEOS-4" as a modelname
                          - changed default PSURF from 986 mb to 984 mb
  clh & bmy, 18 Oct 2002: GAMAP VERSION 1.52:
                          - Now supports 7-layer MOPITT grid
        bmy, 12 Dec 2003: GAMAP VERSION 2.01
                          - Now supports "GEOS4_30L" grid
                          - Set NTROP=18 for GEOS-4 grid   
                          - Now set CENTER180=1 for GISS_II_PRIME 
                          - Now supports 52-layer NCAR-MATCH model 
                          - Cleaned up code and straightened out logic
                          - Removed SMALLCHEM, HELP keywords
        bmy, 18 Feb 2004: GAMAP VERSION 2.01a
                          - The actual NTROP from the GEOS-4 annual
                            mean tropopause is 17, not 18
        bmy, 17 Jun 2004: GAMAP VERSION 2.02a
                          - added GCAP model type for the 23L hybrid
                            GCAP grid (which is the same grid as the
                            winds for the GISS-II-PRIME)
        bmy, 01 Jun 2006: GAMAP VERSION 2.05
                          - Bug fix: GISS-II model needs CENTER180=0
  bmy & phs, 16 Aug 2007: GAMAP VERSION 2.10
                          - Modified for 47 layer GEOS-5 grid
                          - Now return NLAYERS, NTROP, HALFPOLAR,
                            CENTER180, FULLCHEM, HYBRID as type long
        bmy, 06 Aug 2010: GAMAP VERSION 2.14
                          - Added MERRA (identical to GEOS-5 grid, 
                            but retains MERRA name for clarity.)
        bmy, 28 Nov 2010: GAMAP VERSION 2.15
                          - Make the default PSURF value 1013.25 hPa,
                            (i.e. 1 atm) instead of 984hPa.
        bmy, 02 Feb 2012: GAMAP VERSION 2.16
                          - Add GEOS57 and GEOS57_47L grids, for
                            GEOS-5.7.x met data.  (These are
                            identical to the GEOS-5 and MERRA grids,
                            but we will denote them separately).
                          - Added shorthand for 0.25 x 0.3125 resolution

(See /n/home09/ryantosca/IDL/gamap2/gamap_util/ctm_type.pro)


CTM_VALIDATESTRUCTURES

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
        CTM_VALIDATESTRUCTURES

 PURPOSE:
        Test validity of a FILEINFO and DATAINFO structure
        or array of structures.

 CATEGORY:
        GAMAP Internals, Structures

 CALLING SEQUENCE:
        CTM_VALIDATESTRUCTURES,FILEINFO,DATAINFO,result=result, $
              print_warn=print_warn

 INPUTS:
        FILEINFO -> A FileInfo structure (array) to be tested

        DATAINFO -> A DataInfo (array) to be tested

        Both arguments must be present!

 KEYWORD PARAMETERS:
        RESULT -> A named variable that will be set to 1 if
            both structures are valid. This keyword is mandatory.

        PRINT_WARN -> print a warning message on the screen if
            a structure is non-existent or corrupt.

 OUTPUTS:
        None

 SUBROUTINES:
        Uses ROUTINE_NAME and CHKSTRU functions

 REQUIREMENTS:
        None

 NOTES:
        None

 EXAMPLE:
        CTM_VALIDATESTRUCTURES,FileInfo,DataInfo,result=result
        if (not result) then return

 MODIFICATION HISTORY:
        mgs, 20 Aug 1998: VERSION 1.00
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10

(See /n/home09/ryantosca/IDL/gamap2/internals/ctm_validatestructures.pro)


CTM_WRITEBPCH

[Previous Routine] [Next Routine] [List of Routines]
 NAME:
        CTM_WRITEBPCH

 PURPOSE:
        Save GAMAP datainfo records to disk 
        (in binary punch file format).

 CATEGORY:
        GAMAP Utilities, BPCH Format

 CALLING SEQUENCE:
        CTM_WRITEBPCH, DATAINFO, [, Keywords ]

 INPUTS:
        DATAINFO -> a datainfo record or an array of datainfo records
 
        FILEINFO -> a fileinfo record or an array of fileinfo records

 KEYWORD PARAMETERS:
        FILENAME -> Filename of output file. Should end in '.bpch'.

        SCALE -> An optional scaling factor. This factor will be applied 
             to _all_ data record upon saving. The globally stored records
             are not affected.

        NEWUNIT -> With this keyword you can change the unit _name_ for
             the saved data. This will _not_ perform a unit conversion!
             For a true unit conversion you must also use the SCALE
             keyword. NEWUNIT will be applied to _all_ records!

        /APPEND -> If set, then will append to an existing binary
             punch file rather than writing to a new file.

 OUTPUTS:
        A binary punch file with the selected data records will be
        created.

 SUBROUTINES:
        External Subroutines Required:
        ====================================================
        CHKSTRU      (function)   CTM_DIAGINFO
        CTM_GET_DATA (function)   DATATYPE     (function)   
        OPEN_FILE

 REQUIREMENTS:
        None

 NOTES:
        This routine forces reading of all selected data records via
        CTM_GET_DATA.  This may take a while for huge ASCII punch files.

 EXAMPLE:
        gamap [,options]  ; call gamap to read records from a file
        @gamap_cmn        ; get global datainfo structure
        d = *pglobalDataInfo 
        ind = where(d.tracer eq 2)  ; select all Ox records
        ctm_writebpch,d[ind],filename='oxconc.bpch'
        
 MODIFICATION HISTORY:
        mgs, 20 May 1999: VERSION 1.00
                          - stores binary files version 1
        mgs, 24 May 1999: VERSION 2.00
                          - stores binary files version 2
        bmy, 26 Jul 1999: VERSION 2.01
                          - now call function DATATYPE
                          - make sure only floating point data gets
                            written to binary punch file v. 2.0
        bmy, 19 Jan 2000: - updated commetns
        bmy, 07 Jun 2000: GAMAP VERSION 1.45
                          - Save TRACER mod 100L to the punch file 
                          - updated comments
        bmy, 02 Mar 2001: GAMAP VERSION 1.47
                          - added FILEINFO as an argument; will use
                            PGLOBALFILEINFO structure if not passed
                          - removed obsolete comments
        bmy, 13 Mar 2001: - now supports Windows, MacOS, and Unix/Linux
        bmy, 07 Jun 2001: - removed obsolete code from 7/26/99
  mje & bmy, 17 Dec 2001: GAMAP VERSION 1.49
                          - added /APPEND keyword in order to
                            append to an existing binary punch file
                          - updated comments
        bmy, 15 Oct 2002: GAMAP VERSION 1.52
                          - added LEVELSAVE keyword to define certain
                            levels which to save to disk
                          - Updated comments, cosmetic changes
        bmy, 19 Nov 2003: GAMAP VERSION 2.01
                          - now get diagnostic spacing from CTM_DIAGINFO
                            and write TRACER mod SPACING to the BPCH file.
        bmy, 27 May 2004: GAMAP VERSION 2.02
                          - Bug fix: Don't call CTM_GET_DATA to initialize
                            data pointers if this has been done already
                          - removed LEVELSAVE keyword
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10
                          - Now save 4D datablock if the tag
                            of FILEINFO[0].FILETYPE = 106;

(See /n/home09/ryantosca/IDL/gamap2/gamap_util/ctm_writebpch.pro)


CTM_WRITENC

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 NAME:
        CTM_WRITENC

 PURPOSE:
        Save GAMAP datainfo records to disk (in netCDF format)

 CATEGORY:
        GAMAP Utilities, Scientific Data Formats

 CALLING SEQUENCE:
        CTM_WRITENC, DATAINFO, FILENAME=FILENAME

 INPUTS:
        DATAINFO -> a datainfo record or an array of datainfo records

 KEYWORD PARAMETERS:
        FILENAME -> Filename of output file. Should end in '.bpch'.

        SCALE -> An optional scaling factor. This factor will be applied 
             to _all_ data record upon saving. The globally stored records
             are not affected.

        NEWUNIT -> With this keyword you can change the unit _name_ for
             the saved data. This will _not_ perform a unit conversion!
             For a true unit conversion you must also use the SCALE
             keyword. NEWUNIT will be applied to _all_ records!

 OUTPUTS:
        A binary punch file with the selected data records will be
        created.

 SUBROUTINES:
        External Subroutines Required:
        ====================================
        CTM_GET_DATA
        OPEN_FILE
        DATATYPE

 REQUIREMENTS:
        Must have a version of IDL w/ the netCDF library installed.

 NOTES:
        This routine forces reading of all selected data records via
        ctm_get_data. This may take a while for huge ASCII punch files.

 EXAMPLE:
        gamap [,options]  ; call gamap to read records from a file
        @gamap_cmn        ; get global datainfo structure
        d = *pglobalDataInfo 
        ind = where(d.tracer eq 2)  ; select all Ox records
        ctm_writebpch,d[ind],filename='oxconc.bpch'
        
 MODIFICATION HISTORY:
        mgs, 20 May 1999: GAMAP VERSION 1.47
                          - adapted from "ctm_writebpch.pro"
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10

(See /n/home09/ryantosca/IDL/gamap2/gamap_util/ctm_writenc.pro)


CUM_TOTAL (FUNCTION)

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 NAME:
        CUM_TOTAL (function)

 PURPOSE:
        Compute cumulative total of a data vector.

 CATEGORY:
        Math & Units

 CALLING SEQUENCE:
        RESULT = CUM_TOTAL(Y)

 INPUTS:
        Y -> The data vector

 KEYWORD PARAMETERS:
        None

 OUTPUTS:
        A data vector with the same number of elements 
        and the cumulative totals.

 SUBROUTINES:
        None

 REQUIREMENTS:
        None

 NOTES:
        See also function RUN_AV. 

 EXAMPLE:
        Y = FINDGEN(10)
        PRINT, CUM_TOTAL(Y)

             ; IDL prints:  0  1  3  6  10  15  21  28  36  45

 MODIFICATION HISTORY:
        mgs, 21 Oct 1998: VERSION 1.00
        bmy, 23 May 2007: TOOLS VERSION 2.06
                          - Now use longword for loop counter
                          - Updated comments, cosmetic changes
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10

(See /n/home09/ryantosca/IDL/gamap2/math_units/cum_total.pro)


CUSTOM_COLORTABLE

[Previous Routine] [List of Routines]
 NAME:
        CUSTOM_COLORTABLE

 PURPOSE:
        Defines various customized color tables for use with MYCT.
        Color tables may be stretched to more than the original #
        of colors, or compressed to less than the original # of 
        colors.  You may add more color tables as necessary.

        %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
        %% AS OF GAMAP v2-12, CUSTOM_COLORTABLE IS DEPRECATED.  %%
        %% MYCT NOW LOADS IDL AND ColorBrewer COLORTABLES FROM  %%
        %% THE "gamap_colors.tbl" FILE. (phs, bmy, 4/21/08)     %%
        %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
        
 CATEGORY:
        Color

 CALLING SEQUENCE:
        CUSTOM_COLORTABLE, R, G, B [ , Keywords ]

 INPUTS:
        None

 KEYWORD PARAMETERS
        /BuWhRd -> Set this switch to load the BLUE-WHITE-RED 
             (diverging) color table from Harvard University.  This
             color table is a concatenation of the WHITE-BLUE and
             WHITE-RED ColorBrewer colortables.  The center color
             is white.  (Original # of colors = 19)

        /BuWhWhRd -> Set this switch to load the BLUE-WHITE-WHITE-RED 
             (diverging) color table.  This is a concatenation of 
             the WhBu and WhRd colortables from ColorBrewer.  The two
             center colors in this colortable are white, which makes
             it easier to align colorbar tickmarks at the divisions
             between colors.  (Original # of colors = 20)

        /BuYlRd -> Set this switch to load the BLUE-YELLOW-RED 
             (diverging) color table from ColorBrewer.  (Original 
             # of colors = 12)

        /BuYlYlRd -> Set this switch to load the BLUE-YELLOW-YELLOW-RED 
             (diverging) color table from ColorBrewer.  The two center
             colors in this colortable are light yellow, which makes
             it easier to align colorbar tickmarks at the divisions
             between colors.  Use this colortable instead of /BuWhWhRd 
             if you need to denote "missing data" values by white.  
             (Original # of colors = 12)

        /DIAL -> Set this switch to load the DIAL/LIDAR (diverging)
             color table from Ed Browell. (Original # of colors = 27)

        /DIFF -> Synonym for /BuWhRd.  Kept for backwards compatibility.

        /ModSpec -> Set this switch to load the MODIFIED SPECTRUM
             (diverging) color table from ColorBrewer.  (Original #
             of colors = 11)

        NAME -> Returns to the calling program the name of the color
             table that we have selected.

        NCOLORS -> The number of colors that you would like to be
             included in the colortable.  If NCOLORS is greater than
             the native number of colors for the given colortable,
             the colortable will be stretched to produce a finer
             gradation of colors.  Conversely, if NCOLORS is less
             than the native number of colors, then the colortable
             will be compressed to produce a coarser gradation of
             colors.

        /NOLOAD -> If set, then CUSTOM_COLORTABLE will just return R, 
             G, B to the calling program without loading the colortable.

        /TRUNCATE -> When NCOLORS is less than the number of colors
             in the given color table, setting /TRUNCATE will cause 
             CUSTOM_COLORTABLE to truncate the color table to NCOLORS
             rather than trying to compress it via interpolation.

        /UserDef -> Set this switch to load a user-defined colortable.
             In order to use this option, you must first add the R, G,
             B color vectors into internal routine DEFINE_UserDef.

        /WhBu -> Set this switch to load the WHITE-BLUE (spectral)
             color table from ColorBrewer.  (original # of colors = 10)

        /WhGrYlRd -> Set this switch to load the WHITE-GREEN-YELLOW-RED
             (spectral) color table from A. van Donkelaar.  (Original
             # of colors = 20)

        /WhGyBk -> Set this switch to load the WHITE-GRAY-BLACK 
             (spectral) color table from ColorBrewer.  (Original # 
             of colors = 10)

        /WhRd -> Set this switch to load the WHITE-RED (spectral) color
             table from ColorBrewer.  (original # of colors = 10)

 OUTPUTS:    
        R -> Returns to the calling program the red color
             vector that defines the customized colortable.

        G -> Returns to the calling program the green color
             vector that defines the customized colortable.

        B -> Returns to the calling program the blue color
             vector that defines the customized colortable.

 SUBROUTINES:
        Internal Subroutines Included:
        ================================================    
        DEFINE_BuWhRd     DEFINE_BuWhWhRd   DEFINE_BuYlRd   
        DEFINE_BuYlYlRd   DEFINE_DIAL       DEFINE_MODSPEC  
        DEFINE_WhBu       DEFINE_WhGrYlRd   DEFINE_WhRd     
        DEFINE_WhGyBk

 REQUIREMENTS:
        None

 NOTES:
        (1) For contour plots, the native resolution of the
            custom colortables should be sufficient.

        (2) For smoothed pixel plots, NCOLORS=100 or higher will
            eliminate the streaking caused by TVIMAGE's smoothing
            algorithm.

        (3) Some color tables were adapted from the ColorBrewer
            package (see license info below).

        (4) We will use the ColorBrewer color abbreviations:
               Bk = Black    Br = Brown    Bu = Blue      
               Gr = Green    Gy = Gray     Or = Orange    
               Pi = Pink     Pu = Purple   Rd = Red     
               Wh = White    Yl = Yellow

        (5) An MS Excel spreadsheet with all ColorBrewer color tables 
            is available for download from:
            www.personal.psu.edu/cab38/ColorBrewer/ColorBrewer_RGB.html

 EXAMPLES:

        CUSTOM_COLORTABLE, R, G, B, /NOLOAD, /DIAL

             ; Returns the red, green, blue color vectors for the
             ; DIAL colortable at native resolution (26 colors)

        CUSTOM_COLORTABLE, NCOLORS=120, /DIAL

             ; Loads the DIAL colortable and stretches it 
             ; from 26 to 120 colors.

        CUSTOM_COLORTABLE, /WhGrYlRd

             ; Loads the WHITE-GREEN-YELLOW-RED (spectral) 
             ; color table with 20 colors.
        
 MODIFICATION HISTORY:
  bmy & phs, 13 Jul 2007: GAMAP VERSION 2.10
                          - Adapted from "dial_ct.pro"
                          - Now can compress the colortable if
                            NCOLORS is less than N_ORIG
                          - Added /BuWhWhRd keyword for selecting
                            the BLUE-WHITE-WHITE-RED colortable
                          - Added /BuYlYlRd keyword for selecting
                            the BLUE-YELLOW-YELLOW-RED colortable
                          - /DIFF is now a synonym for /BuWhWhRd
                          - Added /UserDef keyword and internal
                            routine DEFINE_UserDef for selecting
                            a user-defined color table. 
        phs, 12 Feb 2008: GAMAP VERSION 2.12
                          - Now create /BuWhRd as a concatenation of
                            the /WhBu and /WhRd colortables.
                          - Updated the interpolation for case of  
                            NCOLORS lt NORIG.  It works fine with all 
                            the 4 diverging colortables, and keeps the 
                            doubling of the middle range color if NCOLORS 
                            is even and BuWhWhRd or BuYlYlRd is used. 
        bmy, 18 Apr 2008: - Bug fix: don't overwrite colortable name
                            for BuWhRd colortable 

(See /n/home09/ryantosca/IDL/gamap2/color/custom_colortable.pro)