Hello Giuseppe, I am too lazy to calculate binary representation of your numbers, but your suspicion of insufficient precision of float seems to be spot-on.
If output is set to DCELL, then the result is exactly as you would expect. Try yourself: r.mapcalc expression="output=basin - 241981407231.0" Range of data: min = 1 max = 3024784769025 Māris. _______________________________________________ grass-user mailing list grass-user@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/grass-user