Hi I think r.profile[1] can probably help you get to the output you want. In the past I had looked into doing the exact same thing as you. I ended up using SAGA GIS[2], as it has a predefined module that does exactly this task, and I was in a hurry ;)
Good luck [1] - http://grass.itc.it/grass64/manuals/html64_user/r.profile.html [2] - http://www.saga-gis.org On Thu, Jul 15, 2010 at 8:41 PM, John C. Tull <[email protected]> wrote: > Hi John, > You will likely get a more complete answer from others, but you seem to be > on the right track with v.drape. From there, you can add a column for > cumulative length with v.db.addcol, then run v.to.db with option=length to > add a length column to your 3d vector. You might be able to subsample from > there. > Another possibility would be to run v.segment to generate points at your > desired length interval for the original vector. Then you could run v.drape > on the resulting points file and work from there or somehow pipe the point > coordinates into r.profile. > Good luck, > John > On Jul 15, 2010, at 12:25 PM, John Callahan wrote: > > Hopefully a quick question that I'm struggling with. (I'm a long-time GIS > user but trying to move my work to GRASS and other FOSS4G.) I'm using > GRASS 6.4 RC6 on Windows XP. > > I have a raster grid representing elevation at 2meter resolution. I have a > line shapefile representing roads (about 20 roads total). I would like to > get ASCII text files of x,y,z at about 1 or 2 meter intervals along each > road. Any ides of what I can try? > > I thought v.drape might work. This converts my 2D road shapefile to 3D, but > I'm not sure where to go from there. And this doesn't help getting 1 or 2 > meter intervals. I also tried r.profile but this requires input as a > listing of x,y coordinates, not shapefiles. I know there's a step here I'm > missing. > > - John > > ************************************************** > John Callahan, Geographic Information Scientist > Delaware Geological Survey, University of Delaware > URL: http://www.dgs.udel.edu > ************************************************** > _______________________________________________ > grass-user mailing list > [email protected] > http://lists.osgeo.org/mailman/listinfo/grass-user > > > _______________________________________________ > grass-user mailing list > [email protected] > http://lists.osgeo.org/mailman/listinfo/grass-user > > -- ___________________________ ___ __ Ricardo Garcia Silva _______________________________________________ grass-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-user
