Hi Håvard, I found the raster calculator and read the online manual for it, however am still a bit lost. I was also playing with the Style properties and color bands last night to try to accomplish this. I was unable to get a single binary image with the single color (red in this case). I think the understand the r.thin suggestion and that it will thin the single color thick lines for vectorization. Appreciate if you can expand on obtaining a binary skeleton of the one color of the trails.
Thanks again, Nick > On Jul 29, 2015, at 7:18 AM, Havard Tveite <[email protected]> wrote: > > If you are going to use GRASS r.to.vect (for instance through QGIS > Processing), you will need a binary skeleton image. > You could get one by using the raster calculator to extract > your single colour as a binary image, and then GRASS r.thin > (available in QGIS Processing) to get the skeleton. > > Håvard > > On 29/7/2015 8:36:AM, Nick Papadonis wrote: >> Hi Folks, >> >> I have a map with numerous trails in a single color and would like to >> vectorize these. Is there a mode Qgis can be placed in such that a color >> can be selected for inclusion in the vectorization process? I.e. to make >> converting these routes to vector format easier? >> >> Thanks again >> _______________________________________________ >> Qgis-user mailing list >> [email protected] >> http://lists.osgeo.org/mailman/listinfo/qgis-user >> _______________________________________________ Qgis-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/qgis-user
