> > Tomas Lanczos wrote: > >> I have contour maps converted to rasters (rock temperatures) in > >> different depths (-500, -1000, -1500, -2000, -2500, -3000, -4000, -6000 > >> meters below sea level). What is the best way to interpolate them to one > >> 3d raster (volume)?
Hamish wrote: > > for evenly spaced raster slices first set the 3D region, e.g. > > g.region t=-500 b=-6000 tbres=500 > > > > then use the r.to.rast3 module to make the 3D raster volume map. > > > > but you would need to interpolate intermediate levels for missing slices. > > For -3500 you could use r.series method=average, for 4500,5000,5500 you > > would have to use r.mapcalc manually. > > > > v.vol.rst could be used to interpolate from 3D points, but RST+contour > > lines usually is prone to artifact problems do to the uneven spatial > > distribution of data points. > > > > see also the 3D help page on the wiki site: > > http://grass.gdf-hannover.de/wiki/Help_with_3D Tomas wrote: > I experimented a lot with this, Your way described below was the easiest > and fastest but the result is not very satisfying for me becasue the > produced "stripes" in the vertical slices (see the picture). If you look at just the -500, -1000, -1500, -2000, -2500, -3000 slices you have, with no r.series interpolation, do you see the stripe? If 0 is the top, it looks like the -2500m values are misplaced?? Also if you are just doing a linear interpolation you can use r.series in multiple passes instead of r.mapcalc, first calculate -5000 from average or -4000 and -6000 maps, then take average of new -5000 and -4000 for -4500 map, etc. Maybe less chance to go wrong then. You can do a slide show of the slices, with d.slide.show, xganim, or the new Tcl animation program in 6.3. Find the min/max range of all the maps and then set & use common color rules for all maps. > I also tried to extract points using r.random (3%), and interpolate using > v.vol.rst but after 12 hours of computing and reaching approx. 20% I > gave it up. What is the best optimalization method for interpolation in > v.vol.rst? Lower XY resolution? Or just leave it running over the weekend.. Hamish ____________________________________________________________________________________ Get easy, one-click access to your favorites. Make Yahoo! your homepage. http://www.yahoo.com/r/hs _______________________________________________ grass-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-user
