The Box is defined by the position of its corner in Physical Coordinates in
the Plot Page by command
SET BOX_LOCATION Xmin Xmax Ymin Ymax
The default Box for the default Plot Page can be accessed by typing SET BOX LANDSCAPE or SET BOX PORTRAIT as required. This default
box is however usually inadequate for maps, where the User Coordinates in X
and Y may be related. The box must of course stay within the limits of the
PLOT_PAGE, so that attempts to define a PORTRAIT page in a LANDSCAPE page
(or vice versa) will fail: an apropriate SET PLOT_PAGE should have been
issued before the SET BOX command.