Hi Thomas, On Wed, 24 Jun 2009 08:42:11 +0200 "Thomas Becker" <[email protected]> wrote:
> Hi, > > I know it is pretty standard to subtract to maps from each other and I do have > the command for r.mapcalc, but it is not doing what I expect. > > I have a landcover map and a map wit buildings. Both are raster maps. Now I > want to get rid of the areas in the landcover map that are covered by > buildings. To get this done I wrote: > > r.mapcalc "newmap = landcover - buildings" if I understand right this might work for you, if everything that is not a building in your 'buildings' map is no data (null): r.mapcalc "newmap = if(isnull(buildings),landcover,null())" > The outcome is a map showing only the buildings and no landcover. It also > doesn't matter if I change the order in the equation, the result is the same: > Only buildings are delivered. > > Can you help me out with this? > > Thanks, > Thomas Regards, Otto _______________________________________________ grass-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-user
