[GRASS5] v.digit topology question

Michael Barton 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

Phone: 480-965-6262
Fax: 480-965-7671

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