GDMAP plots data from a scalar grid.


INPUT PARAMETERS
 
    GDATTIM   *Grid date/time
    GLEVEL    *Grid level
    GVCORD    *Grid vertical coordinate
    GFUNC     *Grid function
    GDFILE    *Grid file
    GAREA     *Graphics area
    SKIP      *Skip factor
    POSN      *Position
    COLORS    *Color list
    MARKER    *Marker color/type/size/width/hw
    MAP       *Map color/dash/width
    LATLON    *Line color/dash/width/label/inc
    PANEL     *Panel location/color/dash/width
    CINT      *Contour interval/min/max
    TITLE     *Title color/line/title
    SCALE     *Scaling factor
    DEVICE    *Graphics device
    PROJ      *Map projection/angles/margins
    CLEAR     *Clear screen flag
    TEXT      *Text size/font/width/hw flag
    GRDLBL    *Grid point label color
 
 
PROGRAM DESCRIPTION
 
    GDMAP plots data computed from GEMPAK grid files on a map.

    The variable, POSN, is used to select the position for the
    data relative to the grid point using the following position
    numbers:

				7
			1		3
			2	0	4
			5		6
				8

    Position 0 will plot data centered at the station.  If an
    invalid position number is entered, position 0 will be used.

    The variable, SCALE, is used to scale the data by 10 ** SCALE.
    The data will be scaled and then rounded to the nearest
    integer before it is plotted.

    SKIP specifies the number of grid points to skip when displaying
    the data.  For example, SKIP = 1 displays data at every other
    grid point in each coordinate direction.  SKIP = 0 displays all
    points.

    If GRDLBL is not 0, the grid point row and column numbers will be
    displayed using the color number specified.  The grid rows and
    columns will be centered on the plot area.

    A map and title may also be included.


EXAMPLES
 
    1.  The temperature field at 850 mb will be plotted in color 3
        at position number 7 which is directly above the station.
        The data will be plotted at every point for an area
        centered on California.  Markers will be plotted at grid
        points.  The title, "Temperature" will be writted in color
        6.

        GDATTIM  =  303/12
        GLEVEL   =  850
        GVCORD   =  pres
        GFUNC    =  tmpc
        GDFILE   =  ngm.grd
        GAREA    =  ca
        SKIP     =  0
        POSN     =  7
        COLORS   =  3
        MARKER   =  1/5
        MAP      =  2/2
        LATLON   =
        PANEL    =  0
        TITLE    =  6//Temperature
        SCALE    =  0
        DEVICE   =  sg
        PROJ     =  mer
        CLEAR    =  yes
        TEXT     =
        GRDLBL   =  0

    2.  Add the dewpoint depression to the plot, in position 8,
        which is directly below the grid point.  The map, markers
        and title are turned off since they are already plotted.

        GFUNC    =  sub[tmpc;dwpt]
        POSN     =  8
        MARKER   =  0
        MAP      =  0
        TITLE    =  0
        CLEAR    =  no

    3.  Now clear the screen and plot the relative vorticity of
        the gridded wind, scaled by 10**5, centered at the station
        in color 1.  Add a map and title in color 1.  Omit the
        markers since the data will overlay them.

        GFUNC    =  vor[wnd]
        COLORS   =  1
        MAP      =  1
        SCALE    =  5
        TITLE    =  1
        MARKER   =  0
        CLEAR    =  yes
        POSN     =  0

ERROR MESSAGES
 
    [GDMAP  -1]     Fatal error initializing TAE.
    [GDMAP  -2]     Fatal error reading TAE parameters.
    [GDMAP  -3]     Fatal error initializing GEMPLT.