Trond Rinde trinde at donau.boku.ac.at
Fri Jul 1 18:29:57 EDT 1994


I have delineated polygon boundaries from a scanned image and imported
it into a raster map layer in grass. Then, after using "r.thin" on the
boundary lines, I converted the polygons to a vector layer using 
"r.line" with option "type=area". All that worked fine, and I got a map
layer with 363 lines, 263 nodes, 118 areas and 8 isles. Now, from these
polygons I want to create a raster map where all the cells within a
polygon has a certain category value. The result should be a patchy mosaic 
of polygons with different colors. To achieve this I use "v.support" on the
converted vector-map to create topology and to assign categories to the
polygons. Then I use "v.to.rast" to re-convert the polygons from vector to 
raster format.

I am obviously doing something wrong, because all I get is an empty raster 
layer. My region is not changed during the process, neither is the resolution 
and I believe I did assign category labels to the polygons (like it is 
said in the manual) when I ran "v.support". 

If anyone see the problem I would appreciate some hints.

Trond Rinde


Siv.ing. Trond Rinde

Institut f. Wasserwirtschaft, Hydrologie und konstruktiven Wasserbau
Universitet f. Bodenkultur
A-1190 Wien, Nussdorfer Laende 11

tel: 	1 36 92 924 352
fax: 	1 36 92 924 350
email:	trinde at donau.boku.ac.at


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