Here's a arcgrid ascii header, obtained by converting mask_map (in ./cmd), using gstat -e conv -f a mask_map mask_map.ag NCOLS 80 NROWS 115 XLLCORNER 178400 YLLCORNER 329400 CELLSIZE 40 NODATA_VALUE -9999 No empty lines above or below; the entries speak for themselves I'd say. Best regards, -- Edzer