gempak command

1. user interface:

• text-based,
• case-insensitive, and
• handles aliases and abbreviations.

list : l

run : r

exit : e
phelp : p    
Most used commands:
save abc # save the current setting to abc.nts
rest abc # load setting in abc.nts
l device # list device value 
p device # help page on device

2. help page:

GEMPAK-GDPLOT2>  phelp    gdinfo    # help info on command  

GEMPAK-GDPLOT2>  phelp    gdfile     # help ino on parameter

GDFILE: grid file name

   filename with path  :  GDFILE   = /export-3/gfs/gfs_2015100906f060

   file type:   GFS GFS model grid

         Remote directories are specified in the table, datatype.tbl.

         eg: GDFILE   = GFS|20151009/0600

               GDATTIM = f060

              

GDATTIM is the date/time for the grid.

The standard format for a grid time is a character string

 YYMMDD/HHMMthhhmm

where:

 YYMMDD    is the year, month, day    # eg : 151013/0600F300

 /    is the date and time separator

 HHMM    is the hour, minute

 t    is the type

                    ( F=forecast  A=analysis  G=guess  I=initial )

 hhhmm    is the forecast hour, minute

If t is blank, an analysis grid is assumed.  

The hhhmm field cannot be omitted if the type is given.  

If hhhmm has one, two, or three digits, they represent hours.  

With four or more digits, zeros will be added at the beginning of the field.

OUTPUT

OUTPUT determines the output devices.  The valid devices are the

terminal (T), a file (F) or none (N).

If N appears anywhere in the output string other than in the file name

no output will be generated.

Eg:

OUTPUT =               --     when no output device is specified, is sent to the terminal

OUTPUT =    f / data.dat    --    output will be written to data.dat

OUTPUT =    tf            --    output sent to the terminal and to the file program.fil

                       where program is the GEMPAK program being run.

DEVICE

DEVICE specifies the graphics device:
device | name | xsize ; ysize | color type

The following graphics devices are available:
XW X Windows terminal
PS PostScript
NC NTRANS Computer Graphics Metafile
GF GIF file using X-server
GIF GIF file not using X-server
UTF Universal Transmission Format (AFOS)
RBK AWIPS RedBook Graphics
VG Vector Graphics (N-AWIPS Product Generation)
XWP Combination driver
FAX Fax driver
TIFF TIFF file

Eg: 
DEVICE = gif | sref_alaska_009_precip_p06.gif | 1024 ; 768

GDPFUN

GDPFUN specifies a grid diagnostic function which yields either a

scalar or vector quantity.  For more information, see the GPARM

documentation.

TYPE

TYPE specifies the processing type for the GDPLOT2 GDPFUN parameter.

The TYPE list does not need separators, however slashes could be

used for clarity:

 type 1 / type 2 / ... / type n

Valid inputs for type are:

SCALAR TYPEs:

       C       the original GEMPAK contouring algorithm

       F       contour fill algorithm

       X       box algorithm -- same as contour fill, but draws lines

               around the polygons rather than filling in polygons.

       P       plot grid point values

       D       plot scaler as a directional arrow

       VECTOR TYPEs:

       A       wind arrows

       B       wind barbs

       S       streamlines

       OTHER TYPEs:

       M       plot grid point markers

       G       plot grid indices (row/column numbers)

     Note that contour attributes are specified in CONTUR.  The contour

     interval and line characteristics for types C, S and X are read

LINE  ( contour line )

LINE is the color, line type, line width, line label freqency,

smoothing separated by slashes, and flag to suppress small contours.  The

individual values in each group are separated by semicolons:

colr1;..;colrn / type1;..;typen / width1;..;widthn / labl1;..;labln / smth / fltr / scf

scf : suppress small contour flag

For example:

               colr   type  wid    lbl    smth  scf

   LINE = 1;2   / 7;8  / 4;5  /   2   /    2    /  T

- colr   : contour line color

- type  : contour line type

- wid    : line width

- lbl      : how often to skip contour lines

- smth  

- fltr

- scf

assigns colors 1 and 2 to alternate lines, dashing patterns 7 and 8 to

alternate lines, line widths 4 and 5 to alternate lines, and labels

every other line.  Smoothing level 2 is used on all lines. Contours with

7 points or less wil not be drawn.

If any specification is missing, a default of 1 is used.  Except for the

smoothing, which defaults to 0, or no smoothing.  If a color number of 0

is given, no plotting will be done. The suppress small contour flag will

default to F, drawing small contours.

Information on color selection can be found in the help for COLORS.

labeling:

If the label information is a single number, n, then every nth line

will be labelled.  If the label information is a single number, -n,

then every nth line will be labelled, however, there will not be a break

in the line for the label.  If a label is a sequence of numbers separated

by semicolons, lines corresponding to values other than 0 will be

labelled.  The pattern established will be repeated to accommodate all

lines.

Smoothing:

The smoothing level is an integer which specifies the amount of

smoothing to apply using a parametric curve function.  The current values

are 0, 1 and 2 which correspond to no smoothing and two levels of

increasing smoothing.

filter

The filter is a real value that specifies the amount of filtering of the

points on a line.  Smaller values allow for more points, while larger

values reduce the number of points on the line.  Valid values are in the

range of 0.0 to 1.0.  The default is 0.0 which means that no reduction

in the number of points will occur.

flag to suppress small contours. ( scf : suppress contour flag )

The suppress small contour flag allows the user to specify whether or not

to draw a contour with 7 points or less. The default is F or FALSE which

allows all contours to be drawn. Setting the flag to T or TRUE will have

the small contours not drawn.

CINT

CINT is the contour interval, minimum and maximum values and number

of digits, separated by slashes:

contour interval / minimum / maximum / ndigits

- contour interval :

- minimum : min value of data set

- maximum : max value of data set

- ndigits : contour label

The contour interval may be any real number.  If it is not specified

or if the value is 0, the program will select an interval which will

generate 5 to 10 contour levels.

The minimum and maximum values specify the range of data to use in

selecting contour levels.  If either value is not specified, the

value will be obtained from the range of values in the dataset.  If

the minimum and maximum are equal, that value will be used and only

one contour level will be selected.

A list of two or more contour levels may be entered using semicolons

to separate the individual values.  In this case, the minimum and

maximum are ignored.

A text string may be specified to replace the contour level value as

the contour label. In a list of contour values, enter a value and a

text string separated by an "=" sign. The input format is shown

below:

       value1=label1;value2=label2;...;valueN=labelN

To set the contour label when plotting a single contour level by

setting the minimum and maximum equal, enter the value and the text

string separated by an "=" sign before the first slash. For example:

          value1=label1 / value1 / value1

If the number of digits (ndigits) is specified,  the integer portion

of the contour labels is forced to contain ndigits characters, not

counting the minus sign, if present.  If the the number of characters

in the integer portion is less than ndigits, that portion is expanded

by padding to the left of the leading digit with zeroes.  For example:

if ndigits = 3 and the original label is 15 or -5, the new labels will

be plotted as 015 and -005 respectively.  If the number of characters

in the original label is greater than or equal to ndigits,  the original

label will be unchanged.  Using ndigits = 4, original labels 1260 and

43712 would be plotted as 1260 and 43712, while a label of 580

would be plotted as 0580.  If there are decimal places or scientific

notation in the original labels, everything to the right of the decimal

point will be plotted without change.  Therefore, if ndigits = 3, then

7.25, -12.4, and 6.5E+12 would be plotted as 007.25, -012.4 and

006.5E+12, respectively.

FLINE

     FLINE is the color and fill type to be used for contour fill:

       colr1;..;colrn/type1;..;typen

     The number of fill colors and types needed is one greater than the

     number of fill levels in FINT.  The number of fill colors may be

     entered as a list of color numbers separated by semicolons or a

     range of colors.  The number of fill types may be entered as a list

     of numbers separated by semicolons.  More information on color

     selection can be found in the help for COLORS.

     The fill type may be set any of the following values:

               1               Solid

               2               Slanted Dash

               3               Wide-spaced Slanted Line

               4               Medium-spaced Slanted Line

               5               Zig-Zag Line

               6               Dots

               7               Thin-spaced Slanted Line

     If fill type is set to 0, soild fill is used. If the fill type is

     set to a single negative number, negative values will use the

     absolute value of the fill type, and positive values will be solid.

FINT

FINT is the contour fill interval, minimum and maximum values

separated by slashes:

fill interval / minimum / maximum

The contour fill interval may be any real number.  If it is not

specified or if the value is 0, the program will select an interval

which will generate 5 to 10 contour fill levels.

The minimum and maximum values specify the range of data to use in

selecting the fill levels.  If either value is not specified, the

value will be obtained from the range of values in the dataset.  If

the minimum and maximum are equal, that value will be used and only

one contour fill level will be selected; however, since the number

of colors is one greater than the number of fill levels, two colors

will be needed--the first for filling regions with values less than

the input value and the second for filling regions of greater value.

A list of two or more fill levels may be entered using semicolons

to separate the individual values.  In this case, the minimum and

maximum are ignored.

     WIND

     WIND specifies the wind symbol, size, width, type, and head size

     separated by slashes:

      wind symbol / size / width / type / arrow head size

     The wind symbol contains a letter for symbol type, a letter for symbol

     units and a color number with no separators.  The character meanings

     are:

       TYPE:   B = BARB        A = ARROW               D = DIRECTIONAL ARROW

       UNITS:  K = KNOTS       M = m/s

       COLOR:  Color number    0 = no wind plotted

     The default is BM1, i.e., barbs in meters/sec plotted in color number

     1.  If a partial specification is given, the remaining characteristics

     will be taken from the default.

     The wind size is a real number which will be used as a multiplier for

     the default wind symbol size.  If this number is negative, zero, or

     missing, the current size will be used.  The sizes for barbs and

     arrows are independent.

     The width is an integer specifying the line width to use in drawing

     the arrows or barbs.

     CLRBAR

     CLRBAR specifies the characteristics of a color bar associated with

     contour fill.  The attributes are separated by slashes:

     color / orientation / anchor / x;y / length;width /  frequency | text_info

     Color is the color of the labels and the bounding box around the

     color bar.  If color is negative, the bounding box will not be drawn,

     and labels will be drawn in colors corresponding to the color bar.

     If the color is 0 or missing, no color bar is drawn.

     Orientation specifies a vertical or horizontal orientation of the

     color bar where 'V' is a vertical bar and 'H' is a horizontal bar.

     The default is 'V'.

     Anchor describes the location on the color bar corresponding to

     the location given in the next parameter.  Valid inputs are

     LL, LC, LR, CL, CC, CR, UL, UC, and UR for lower-left, lower-center,

     lower-right, center-left, centered, center-right, upper-left,

     upper-center, and upper-right, respectively.  For example, an 'LL'

     anchor point, with a x;y of .1,.1, will place the lower-left corner

     of the color bar at view coordinates .1, .1.  The default anchor

     point is 'LL'.

     IJSKIP

Syntax
                 Iskp;Istrt;Istp/Jskp;Jstrt;Jstp
     or
                 Yes
     or
                 No

     If IJSKIP = NO, then the results are the same as for IJSKIP set
     to blank or zero. 

    If IJSKIP = YES, then all the skipping values
     are computed automatically.  When IJSKIP = YES, skipping is only
     done if the number of grid points required to cover the display
     area is too large.  The automatic number of points skipped is
     the same in each index direction, and it will be the minimum
     number required to make the internal computational grid fit in
     allocated memory.

     IJSKIP and SKIP are functionally independent.  If SKIP is also
     specified, IJSKIP operates first to create the subset grid,
     then the SKIP information is applied to that subset grid, which
     has already been thinned by IJSKIP.

Since IJSKIP and SKIP are done in series, the combined effect is multiplicative.  


      Example                            Action

     IJSKIP = YES   Skip only if necessary, skipping as few points
                    as possible; if the subset area is reduced fewer
                    points will be skipped

     IJSKIP = 5     Skip 5 points in both index directions; beginning
                    and ending indexes are automatically determined

     IJSKIP = 5/3   Skip 5 points in the I index direction; skip 3
                    points in the J index direction; beginning and
                    ending indexes are automatically determined

     IJSKIP = 5;3/2 Skip 5 points in the I index direction; skip 2
                    points in the J index direction; beginning I
                    index is 3; all other indexes are determined
                    automatically

Gempak color table

            

3. Issues encountered

1) use alias name,  not working

Wrong:

GEMPAK-GDINFO>gdfile=gfs|2015100900/f060

GEMPAK-GDINFO>r

[FL -4]  Cannot read file .... [DM -7]  Read error. [GD -2]  File /export-3/ncosrvnfs-cp/model/grid/gempak/gfs/ cannot be

Right:

GEMPAK-GDINFO>gdfile=gfs|20151009/0600

GEMPAK-GDINFO>gdfile=gfs|20151009/06

2) specify grid file directly, it works.

GEMPAK-GDINFO>l

GDFILE   = /export-3/ncosrvnfs-cp/model/grid/gempak/gfs/gfs_2015100900f060

LSTALL   = YES

OUTPUT   = tf/abc

GDATTIM  = f60

GLEVEL   = all

GVCORD   = all

GFUNC    = all

GEMPAK-GDINFO>r

GRID FILE: /export-3/ncosrvnfs-cp/model/grid/gempak/gfs/gfs_2015100900f060                             

GRID NAVIGATION:

   PROJECTION:          CED              

   ANGLES:                 0.0     0.0     0.0

   GRID SIZE:              360     181

   LL CORNER:           -90.0000    0.0000

   UR CORNER:            90.0000   -1.0000

GRID ANALYSIS BLOCK:

   ANALYSIS TYPE:        BARNES

   DELTAN:               4.000

   DELTAX:           -9999.000

   DELTAY:           -9999.000

   GRID AREA:           -90.00 -180.00   90.00  180.00

   EXTEND AREA:         -90.00 -180.00   90.00  180.00

   DATA AREA:           -90.00 -180.00   90.00  180.00

Number of grids in file:   366

Maximum number of grids in file:   4999

NUM       TIME1              TIME2           LEVL1 LEVL2  VCORD PARM

   1     151009/0000F060                          0         TROP PRES     

   2     151009/0000F060                          0         TROP ICAHT    

   3     151009/0000F060                          0         TROP HGHT     

   4     151009/0000F060                          0         TROP TMPK     

   5     151009/0000F060                          0         TROP UREL     

   6     151009/0000F060                          0         TROP VREL