GDWIND displays a vector grid using wind barbs or arrows.


INPUT PARAMETERS
 
    GDATTIM   *Grid date/time
    GLEVEL    *Grid level
    GVCORD    *Grid vertical coordinate
    GVECT     *Grid vector function
    GDFILE    *Grid file
    GAREA     *Graphics area
    SKIP      *Skip factor
    WIND      *Wind symbol/siz/wdth/typ/hdsz
    MAP       *Map color/dash/width
    LATLON    *Line color/dash/width/label/inc
    PANEL     *Panel location/color/dash/width
    TITLE     *Title color/line/title
    DEVICE    *Graphics device
    PROJ      *Map projection/angles/margins
    CLEAR     *Clear screen flag
    SCALE     *Scaling factor
    TEXT      *Text size/font/width/hw flag
 
 
PROGRAM DESCRIPTION
 
    GDWIND draws wind barbs or arrows at each grid point of a
    vector grid.

    SKIP specifies the number of points to skip in both coordinate
    directions.  For example, SKIP = 1 will display winds at every
    other grid point.  SKIP = 0 displays winds at every grid point.

    IF M is entered as part of the wind symbol, winds will be
    displayed in m/s, unless the KNOTV operator has been specified
    in GVECT, in which case the winds will be displayed in knots.
    If K is entered in WIND, the wind is displayed in knots.


  EXAMPLES
 
    1.  Draw wind barbs in m/s  at every grid point.  The vector field is
        the gridded wind at 850 mb on March 3 at 12Z.  The plot
        is centered on Colorado.

        GDATTIM  =  303/12f00
        GLEVEL   =  850
        GVCORD   =  pres
        GVECT    =  wnd
        GDFILE   =  ngm.grd
        GAREA    =  co
        SKIP     =  0
        WIND     =  bm1
        MAP      =  1/10
        LATLON   =  1/10
        PANEL    =  0
        TITLE    =  1
        DEVICE   =  xw
        PROJ     =  mer
        CLEAR    =  yes
        TEXT     =

    2.  Using the values of the variables supplied above, draw
        arrows at every other grid point.  The vector to be used
        is the temperature gradient.  The screen should not be
        cleared.  The arrows are in color 7.

        GVECT    =  grad ( tmpc )
        SKIP     =  1
        WIND     =  an7
        SCALE    =  5
        CLEAR    =  no

    3.  Plot wind barbs of the gridded wind in knots.  Note that
        WIND = bk1 and WIND = bm1 give the same results when
        KNOTV is used.

        GVECT    =  knotv ( wnd )
        WIND     =  bk1


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