The number and size of plots can be controlled on the "real" page by defining one or more "virtual" pages. The relevent command is:
set vpage xmin xmax ymin ymax
This command defines a "virtual page" that fits within the specified limits of the real page. All graphics output will be drawn into this "virtual page" until another 'set vpage' command is entered. A clear command clears the physical page (and any virtual pages drawn on it).
When GrADS is first started, it prompts for landscape or portrait mode. This defines the size of the real page (11x8.5 or 8.5x11), and the dimensions for the virtual page must fit within this real page.
The 'set vpage' command will define virtual page limits in terms of inches (virtual page inches), which are the coordinates that will be used in the various commands that require inches to be used. The new page limits are printed when the 'set vpage' command completes.
To return to the default state where the real page equals the virtual page, enter:
set vpage off
To control the area within the virutal page that GrADS plots into, use:
set parea xmin xmax ymin ymax
The command specifies the area for plotting contour plots, maps, or line graphs. This area does not include axis labels, titles, etc., so if you need to see those, provide for an adequate margin.
The region is specified in terms of virtual page units. By default, the virtual page is equal to the real page, so the units are approximately inches on the real page.
Maps are scaled to fit within the plotting area such that their correct aspect ratio is maintained. Thus, the map will not fill the entire plotting area except under certain lat/lon ranges. A line graph or a contour plot without a map will be scaled to fit entirely within the specified plotting area.
By default, an appropriate plotting area is chosen depending on the type of graphics output. To return to this default, enter:
set parea off
It is not appropriate to use this command to put multiple plots on one page. It is better to use the 'set vpage' command.