[GRASS-user] Tracing dotted lines from raster (and convert to vector)

Nikos Alexandris nikos.alexandris at felis.uni-freiburg.de
Fri May 23 12:56:59 EDT 2008

> I have found that when you are working with discontinuous line segments that 
> don't have gaps too large -- it is possible to "re-connect" the lines with 
> the following procedure:
> 1. extract only the color of interest
> 2. use r.grow to "fatten" the segments until they touch
> 3. use r.thin to return the segments to linear feature
> 4. vectorize with r.to.vect
> I have used this approach with area features as well. See this link for some 
> ideas:
> http://casoilresource.lawr.ucdavis.edu/drupal/node/244
> Cheers,
> Dylan


it works great. Also here

which might be yours ;-)


It feels good that I also "found" the same way more or less in the end.
I noticed the "trick" of keeping the color of the lines of interest

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