On Jun 6, 2009, at 11:36 PM, Dwight Needels wrote:
Hi all. I have run into a quirk using r.thin, but I am not sure whether or not it is a bug. I have a raster that was generated from multiple GPS tracks using v.rast followed by r.buffer. Using r.thin followed by r.to.vect creates a vector that must then be cleaned using v.clean to remove dangles (so far, so good).The quirk is that r.thin occasionally creates a triangle at the intersection of two lines instead of two intersecting lines. All of the examples I have seen involve relatively acute angles (less than 25 degrees??). I have attached a screenshot that shows the raster in magenta, the vector with dangles in white, and the cleaned vector as (a thinner) green. There are numerous acute angles that generate the vectors I would expect, with one exception in the center.Is this expected behavior? If so, is there an easy way to search for all such resulting triangles in a vector or to remove all such extra lines in a vector? If not, is there a way to fix it?Thanks, -Dwight <r.thin.png> _______________________________________________ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
Although I figured out how to file a bug report on this, http://trac.osgeo.org/grass/ticket/636 , I am not sure how to respond directly to comments on the ticket.
Hamish, I used the screenshot showing the vectors because I had already created it to look for artifacts. The extra line that makes the triangle is also present in the thinned raster (screenshot attached).
Thanks, -Dwight
<<inline: r.thin_raster.png>>
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