Hi, I've been working with v.surf.rst on large datasets, and I can appreciate its scalability when using segmented processing.
However, the wiki page [0] is not very clear on that topic, so I ran a few (very informal) tests for different values of segmax and npmin on a subregion of my study area (449*450=202050 cells): (1) augmentation of npmin values, segmax constant segmax npmin time (real) 20 50 1m27.178s 20 100 3m12.316s 20 150 7m23.835s 20 200 14m18.463s (2) augmentation of segmax values, npmin constant, but have to keep npmin > segmax segmax npmin time (real) 10 100 4m10.401s 15 100 3m37.057s 50 100 1m23.217s 100 150 1m42.070s 200 250 1m34.099s 500 600 3m54.364s (3) for reference, with the other v.surf.* methods: v.surf.bspline 4m04.990s v.surf.idw 0m58.686s So, at the end, I am a bit puzzled about the choices I should take to interpolate the full dataset. I'm very keen on using v.surf.rst, as it improved the computing time a lot on the whole scene (say 20 minutes vs 1 day for v.surf.idw), but I just don't feel comfortable choosing random parameters. Any hint on how to tune those parameters? That would make a great add to the wiki page IMHO. Pierre [0] http://grass.osgeo.org/wiki/RST_Spline_Surfaces -- Scientist Landcare Research, New Zealand _______________________________________________ grass-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-user
