basemap

[Tess Parker]

List - I am using the script basemap.gs to produce a north pole
stereographic map with land areas shaded grey. I am using medium resolution.
My grads commands are:

'open avestn.ctl'
'enable print 'test_ave.gmf'
'set grads off'
'set mproj nps'
'set lon 0 360'
'set lat 70 90'
'set digsize 0.09'
'set dignum 1'
'set stid on'
'set stnprint on'
'set mpdset mres'
'set map 1 1 3'
'd press'
'basemap L 15 0 M'
'draw title Monthly Mean SLP'
'print'
'disable print'

The problem I have is that there are a couple of shaded areas which extend
outside my map; do I need to use another command such as mpvals or something
to get rid of these? There are three biggish blocks of grey outside the 60
lat circle. Any help much appreciated.