By default, when one dimension varies, you get a line graph, and when two dimensions vary, you get a contour plot. This default can be changed:
set gxout graphics_type
where graphics_type is one of:
contour: Contour plot
shaded: Shaded contour plot
grid: Grid boxes with values
vector: Vector wind arrows
stream: Vector streamlines
bar: Bar chart
line: Line Graph
barb: Wind barbs
fgrid: Shaded grid boxes
fwrite: output grid to file called grads.fwrite by default. The data consist of local floats (e.g., 32-bit IEEE big endian floats on a sun/sgi/hp workstation)
For station data:
value: Station values
barb: Wind barbs
wxsym: Wx symbols
findstn: Find nearest station (see scripting language)
There are many options that can be set that control how these grahpics types will be displayed. This will be covered in more detail later.
For the graphics output types of vector, stream, and barb, the display routines need two result grids, where the 1st result grid is treated as the U component, and the 2nd result grid is treated as the V component. To obtain two result grids, you enter two expressions on the display command seperated by a semicolon:
display u ; v
display ave(u,t=1,t=10) ; ave(v,t=1,t=10)
For the types of vector and stream, you can specify a 3rd grid that will be used to colorize the vectors or streamlines:
display u;v;hcurl(u,v)
display u;v;mag(u,v)
For a gxout of wxsym, each value at a station location is assumed to be a wx symbol code number. Hurricane and tropical storm symbols are included in the symbol set.
draw wxsym symbol x y size <color <thickness>>
Draws the specified wx symbol at the specified location. where:
symbol - is an integer specifying what symbol to draw
x - x location, in plotter inches
y - y location
size - size of the symbol (roughly)
color - color of symbol. Use -1 to get standard colors (red for tstorm, blue for snow, etc)
thickness - line thickness of the symbol
To see what symbols are available, run grads, then:
run /local/lib/grads/wxsym.gs
You may look at this script to see how to issue the wxsym command.