On Sat, Apr 6, 2013 at 4:25 PM, epi <massimodisasha at gmail.com> wrote: ... > GRASS 7.0.svn (utm19N_wgs84):~ > r.fillnulls input=dtm1 output=dtm1 > --overwrite You try to overwrite the source with the target, to my knowledge invalid (sure, the module should say so). Try r.fillnulls input=dtm1 output=dtm1_filled Markus