[GRASS5] v.digit topology question
michael.barton at asu.edu
Wed Oct 29 15:10:14 EST 2003
Experimenting with GRASS 5.7, I've managed to make a great vector shape
using v.digit. I very much like the interface--much simpler than
ArcView/ArcGIS, and certainly much easier than the v.digit of GRASS
5.0.x (although with fewer options it seems).
However, something is driving me crazy. I've probably missed something,
but hope someone can help me. I've digitized a boundary, but can't
figure out how to turn it into an area. When I do a right-click after
digitizing a shape, the implication is that it will close a polygon,
creating an area. It doesn't seem to do this,however.
I've tried inserting a centroid, doing various versions of v.clean,
v.build.polylines, and v.build to no avail. After exporting into ascii,
cleaning up some tiny segments produced at line intersections (how
produced I don't know, perhaps by v.clean), and reimporting, I managed
to get it down to a single polyline boundary. But I still can't convert
it to an area.
After several hours of futzing around, I give up. Can anyone tell me
how to do this?
Also, please note that when I do a v.out.ascii on this boundary file,
it creates a file that GRASS 5.0.x won't parse. I assume that it has
something to do with assigning "B" labels for boundary vertices, rather
than "A" or "L" labels, but I don't know for sure. I haven't yet tried
exporting in version 4 format. Maybe that will work.
C. Michael Barton, Professor
Department of Anthropology
PO Box 872402
Arizona State University
Tempe, AZ 85287-2402
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