Hi, I have solved this problem in the past with a combination of g.region, v.to.rast, and r.grow.
For example, if you import your points in as a vector-- convert to raster, increase the cell size, and grow out a couple of cells. If you are bringing in your lidar data with r.in.xyz, then it is already a raster, and you can adjust the resolution and "grow" accordingly. Make sense? Cheers, Dylan On Fri, Dec 18, 2009 at 4:04 AM, John Tate <john.t...@ntlworld.com> wrote: > Hi all, > > For a while now I have been trying to make an accurate mask for LiDAR points. > As I am working with 1m resolution data I want the mask to be accurate (no > more than 1m around the edge of the points/flight area). > > The data is wavy around the edges, due to a windy flight when the data was > collected, so v.hull ignores the waves and joins the crests, adding vast NULL > areas to the mask. Also, there are up to 10m holes within the individual > swaths. > > r.in.xyz at 5m resolution has given me the best results so far as final > accuracy masks, but not for the processing as I want holes within the data > filled with v.surf.rst. > > I have looked at v.delaunay and v.voronoi too, but both need topology built > and don't have similar outputs to v.hull regarding vast NULL areas. This is ok > for 1km tiles, but I want to process each swath separately (study on swath > accuracy) and these can be c.5million points each. > > Does anyone know if there is way to do this accurately without manually > digitizing? Have I missed something in the book/manual? > > Cheers > > John > > _______________________________________________ > grass-user mailing list > grass-user@lists.osgeo.org > http://lists.osgeo.org/mailman/listinfo/grass-user > _______________________________________________ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user