15.4.3  EXPAND 

Sets  the  limits  so  that  the selected data expands to fill the window.
This has no effect unless LIMITED, POINTS, SETS, or SLICES are  specified.
Normally  the  limits of the plot are set according to all data.  This may
inconvenient when the plotted subset of the data  occupies  only  a  small
portion of the window.  EXPAND will make the data fill the window. 
(Default:OFF)