POLYGON

example

 You can use this command is conjunction with the PICK\POLYGON command to
 choose a polygon and the DESTROY command to eliminate data points within
 the chosen polygon, for example:

 READ FILE.DAT X Y      ! read some data
 SET PCHAR -16          ! choose point plotting symbol
 GRAPH X Y              ! display the data graphically
 PICK\POLYGON XP YP     ! choose a polygon around data to eliminate
 POLYGON XP YP X Y KEY  ! create KEY vector
 DESTROY X Y =KEY       ! eliminate unwanted data
 CLEAR
 GRAPH X Y              ! display data without unwanted points