GDSTREAM draws streamlines through a vector grid.

INPUT PARAMETERS
 
    GDATTIM   Grid date/time
    GLEVEL    Grid level
    GVCORD    Grid vertical coordinate
    GVECT     Vector grid
    GDFILE    Grid file
    GAREA     Graphics area
    IJSKIP    Iskp;Istrt;Istp/Jskp;Jstrt;Jstp
    SATFIL    Satellite image filename(s)
    RADFIL    Radar image filename(s)
    IMCBAR    Color/ornt/anch/x;y/ln;wd/freq
    LINE      Color/type/width/label/smth/fltr
    MAP       Map color/dash/width/filter flag
    MSCALE    fgc;bgc;mask/units/lat;hide/values/anch/x;y/ln;wd/freq|text_info|t
    LATLON    Line color/dash/width/freq/inc/label/format
    TITLE     Title color/line/title
    PANEL     Panel loc/color/dash/width/regn
    TEXT      Size/fnt/wdth/brdr/N-rot/just/hw flg
    DEVICE    Device|name|x size;y size|color type
    PROJ      Map projection/angles/margins|drop flag
    CLEAR     Clear screen flag
    WIND      Wind symbol/siz/wdth/typ/hdsz
    LUTFIL    Enhancement lookup table filename
    STNPLT    Txtc/txt attr|marker attr|stnfil#col
    STREAM    lines/arrows/stop/slow/scale
 
 

PROGRAM DESCRIPTION
 
    GDSTREAM draws streamlines through any vector grid computed
    by the grid diagnostics package. The vector grid is specified
    in GVECT.

    Streamlines are plotted in an animation sequence by specifying
    more than one time in GDATTIM.

    The line color, dash pattern and line width are set in LINE.
    A map, title and latitude/longitude lines may also be included.
    The size of the arrow heads may be controlled by specifying
    the fifth value in WIND.

    The STREAM parameter controls several parameters dealing with
    the overall streamline calculation and display.  "Lines" is a
    real number multiplier which controls the number (density) of
    streamlines drawn (default 1.0); "arrows" is a real number
    multiplier which controls the number of arrowheads displayed
    (default 1.5*lines); "stop" is a real number multiplier which
    controls how close a streamline comes to another streamline
    before it is stopped being drawn (default 0.5); "slow" is a
    real number multiplier which controls the minimum vector speed
    threshold for stopping a streamline (default 0.67); "scale" is
    a real number multiplier which controls how much the input vector
    field is scaled prior to streamline calculation (default 0.33).


EXAMPLES
 
    1.  Draw streamlines through the gridded wind field at 850
        mb using color 3.  Add a North Polar Stereographic map
	in color 1 and line type 7 and a title in color 5.
	Center the graphics area on Ohio.

	GDATTIM	 =  f24
	GLEVEL	 =  850
	GVCORD	 =  pres
	GVECT	 =  wnd
	GDFILE	 =  $GEMDATA/hrcbob.grd
	GAREA	 =  oh-
	SATFIL	 =
	RADFIL	 =
	IMCBAR   =
	LINE	 =  3//2
	MAP	 =  1/7
	LATLON	 =  2/10/1/1/5;5
	TITLE	 =  5
	PANEL	 =  0
	TEXT	 =  1
	DEVICE	 =  xw
	PROJ	 =  nps
	CLEAR	 =  yes
	WIND	 =
	LUTFIL   =
	STNPLT   =

    2.  Similar to 1), except for a global 1x1 degree dataset over the
	Pacific Ocean, specifying the STREAM parameter to properly
	thin and display the field given the overall density of
	grid boxes.

	GDFILE   = $MODEL/fnl/fnl_96052800
	GDATTIM	 = f00
	GLEVEL	 = 250
	GAREA    = -25;-180;55;-45
	PROJ     = mer
	LATLON   = 31/12/2//10
	STREAM   = 0.4/0.8/3//
	WIND     = am1/2/3//0.8
	TITLE    = 31/-2/@ FNL ANALYSIS VALID ~         NHC MIAMI FLA

    3.  Clear the screen and draw the streamlines of the thermal
        wind.  Make the arrowheads 0.75 of the default size.
	Plot the streamlines in a second window named "window2".

	GDATTIM	 =  f24
	GLEVEL	 =  500:850
	GVCORD	 =  pres
	GVECT	 =  thrm
	GDFILE	 =  $GEMDATA/hrcbob.grd
	GAREA	 =  oh-
	SATFIL	 =
	RADFIL	 =
	IMCBAR   =
	LINE	 =  3//2
	MAP	 =  1/7
	LATLON	 =  2/10/1/1/5;5
	TITLE	 =  5
	PANEL	 =  0
	TEXT	 =  1
	DEVICE	 =  xw|window2
	PROJ	 =  nps
	CLEAR	 =  yes
	WIND	 =  an3////.75
	LUTFIL   =
	STNPLT   =

ERROR MESSAGES
 
    [GDSTREAM  +2]  WARNING:  ... not found.  CONTINUING---
    [GDSTREAM  -1]  Fatal error initializing TAE.
    [GDSTREAM  -2]  Fatal error reading TAE parameters.
    [GDSTREAM  -3]  Fatal error initializing GEMPLT.

