On Sunday 30 March 2008, Hamish wrote: > Dylan: > > This is slightly incorrect -- as we are growing the cost surface to > > compute the perimeter, when we should be shrinking it. However it > > appears that r.grow cannot use a negative radius. > > create a negative mask, grow that, then invert again: > > > r.mapcalc "inv_mask = if(isnull(mask), 1, null())" > > r.grow in=inv_mask out=inv_mask.grown > > r.mapcalc "mask_shrunk = if(isnull(inv_mask.grown), 1, null())" > > > > Hamish > > >
I haven't looked at the source for r.grow -- does anyone know how much effort it would take so that it could accept a negative "growth radius" ? Dylan -- Dylan Beaudette Soil Resource Laboratory http://casoilresource.lawr.ucdavis.edu/ University of California at Davis 530.754.7341 _______________________________________________ grass-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-user
