The process we use at SPC to create our frontpage maps is rather
complicated, but it gives us the desired effect. These steps are followed
in order to create pixel-for-pixel identical images for our products on the
SPC website front page.
1) GPMAP is used with the following options:
map = 6=140:140:140/1/1
garea = 19.0;-120.1;50.8;-61.3
radfil = <latest 1km mosaic radar image>
proj = rad
text = 1/22//hw
lutfil = white.tbl <sets everything to white>
bnd = bg/30=210:227:244+hcn_bnds/11=g80+state_bnds/1
dev = gf|basemap.gif|640;480
2) Next we use mogrify to crop the image to the correct area
mogrify -crop 582x408+28+36 basemap.gif
Hope this helps!