On Jan 8, 2014, at 12:35 PM, Markus Metz wrote: > On Thu, Dec 12, 2013 at 11:13 PM, John Ciolek <[email protected]> wrote: >> I have automatically generated raster data from which I create a contour >> using r.contour. Sometimes the "feature" to be contoured is not completely >> contained within the specified region. When this happens, r.contour >> generates an open contour - basically the beginning line segment point does >> not equal the ending line segment point. >> >> Is there a way to get r.contour to close the contour at the region's border? > > No. This is a feature of r.contour because it is impossible to tell > where a contour would continue if it hits the region's border. >> >> If not, is there an easy way to close the contour? > > Why do you want to close the contour?
I am trying to create areas from the contours, where the areas clip to the set region. > > If you want to convert the contour lines to areas, you might instead > modify the raster with r.mapcalc, e.g. for contours at every 100 unit > step > > r.mapcalc "surface.classified = int(surface / 100) * 100" > > but here a value of 99 would be converted to 0, thus as an alternative > > r.mapcalc "surface.classified = int((surface + 50) / 100) * 100" > > which would convert e.g. all values >= 50 and < 150 to 100. > > After that the classified raster could be converted to vector areas > with r.to.vect type=area > > HTH, > > Markus M Wouldn't this create a very blocky contour? The contouring is done in batch mode for a real-time modeling system. Right now I'm thinking it would be easiest to write a program to add one extra point to the vector if the first and last points do not match. Was hoping for an easier way. John _______________________________________________ grass-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-user
