Hallo, I try some test on the Spearfish dataset with GRASS 6.1. Is it possible, that r.flow does not support NULL values at least for "barin" raster? I get the right output only with maps with "0" values.. Jachym -- Jachym Cepicky e-mail: jachym.cepicky at centrum.cz URL: http://les-ejk.cz GPG: http://les-ejk.cz/gnupg_public_key/