[GRASS-user] Vectorize rasters

Daniel Victoria daniel.victoria at gmail.com
Tue Oct 10 17:20:24 EDT 2006

Hi all,

I have to vectorize some scanned topographic maps (1:10000 scale, 5
meters contour lines). The maps where scanned with 300 dpi.

The way I'm doing is:
1) r.thin the topo map
2) v.digit the thinned raster
3) v.clean prune and rmdangle and lots of manual editing (rivers and
contour lines are the same color, it's a black and white scan...)
4) manually add the contour values

Are there any other ways of doing this? Would editing the raster with
r.digit help speed up the process. For instance, the raster map
contains the contour text (cotas), shaded areas representing some
special landcover, rivers are the same color as contours etc...


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