Basic Concept of OperationWhen you have successfully installed and started GrADS, you'll be confronted with two windows -- a terminal window with a prompt (ga->), and a resizable window (black background by default) where graphics are displayed.
GrADS commands are entered in the terminal window and the response from GrADS is either graphics in the graphics window or text in the terminal window. The three fundamental GrADS commands:
The GrADS "expression," or what you want to look at, can be as
simple as a variable in the data file that was opened, e.g.,
The "where" of data display is called the "dimension environment"
and defines which part, chunk or "hyperslab" of the 5-D
geophysical space (lon,lat,level,time,ens) is displayed. The
dimension environment is manipulated through the set command and
is controlled in either grid coordinates (x,y,z,t,e indices) or world coordinates (
The "what" and "how" of display is also controlled by the
GrADS graphics can be written to a file (i.e.,
In addition, GrADS includes graphic primitives (e.g., lines and
circles) and basic labelling through the