Thanks a lot for the answers! I managed to identify the range of values containing the grey category values. So, my command became: r.mapcalc grey_raster=if(tragh.red>=132&&tragh.red<=200, 1, null())
It was a little difficult. I had to make it step by step. One way would be to use in addition r.what or r.what.vect to sample the cat values corresponding to my grey zones Thank you -- View this message in context: http://osgeo-org.1803224.n2.nabble.com/Extracting-grey-features-from-an-image-tp5107822p5108384.html Sent from the Grass - Users mailing list archive at Nabble.com. _______________________________________________ grass-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-user
