I also tried that by first setting the region equal to the elevation map and then using r.mapcalc to create a new accumulation map. Both the elevation and accumulation maps have the same spatial extent and resolution, but I still get the error.
I believe that the flow accumulation grid was produced using ArcHydro. I put the link to the data set that I am using below if anyone wants to try it out. http://www.horizon-systems.com/nhdplus/HSC-wth21.php -- View this message in context: http://osgeo-org.1803224.n2.nabble.com/r-stream-extract-with-external-flow-accumulation-maps-tp6518518p6522188.html Sent from the Grass - Users mailing list archive at Nabble.com. _______________________________________________ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
