> I'm wondering if there is a command that builds topology, just like "build" in ArcInfo > and in making polygons out of lines. I had a short look at the v-commands but > couldn't find any of interest. Hi, the v.support (option=build) is used to build up the topology. To change lines to areas, use v.line2area (may be named v.line2area.sh). Cheers Markus