stephen sefick wrote: > I have a multitude of DEMs to generate at 1m resolution. Are there > any references that compare v.surf.idw and v.surf.bspline? Any advice > or experience with either of these two modules would be helpful. > Which one of these modules creates the most accurate representation of > the surface. This will be with NC data- in fact the same 2001 data > that is included in the new GRASS dataset. I am working on a project > in NC if this helps. Thank you for all of your help, and I will > provide any information that you may need. Also, if I use > v.surf.bspline is the 1.5*point average point spacing still the rule > of thumb (the point spacing is found with running v.surf.bspline with > the -e flag?).
The 1.5 * average point spacing is a useful rule of thumb as long as the points are evenly spaced as e.g. for elev_lid792_bepts in the North Carolina sample database. If the points are not evenly spaced, e.g. strips with high density, but the strips are separated by a distance larger than the average within-strip distance (e.g. contours), then the spline step values need to be adjusted, no established rule of thumb here. We need a wiki page explaining the different interpolation methods... Markus M Thank you so much for all of your help. > > -- > Stephen Sefick > ____________________________________ > | Auburn University | > | Department of Biological Sciences | > | 331 Funchess Hall | > | Auburn, Alabama | > | 36849 | > |___________________________________| > | [email protected] | > | http://www.auburn.edu/~sas0025 | > |___________________________________| > > Let's not spend our time and resources thinking about things that are > so little or so large that all they really do for us is puff us up and > make us feel like gods. We are mammals, and have not exhausted the > annoying little problems of being mammals. > > -K. Mullis > > "A big computer, a complex algorithm and a long time does not equal science." > > -Robert Gentleman > _______________________________________________ > 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
