Edit-Polygon-Region Mode

This mode allows you to apply a one by one cell brush to
a polygonal region of the raster map.  You identify the 
polygonal region to be edited by using the mouse to 
draw a polygon on the raster map.

Press and realese the left mouse button to identify the 
first point of the polygon.  As you move away from this
first point you should see a line following the mouse 
cursor.  Press and release the left mouse button again
to identify the next point.  Repeat this until you are
ready to close the polygon.  Press and release the 
right mouse button to identify the last point.

The brush will be applied to all of the cells within the 
identified polygon.  If you do approve of the edit, then
use the @ref("Edit-Undo",xgre/edit_undo) menu option immediately to reverse it. 




