On Sunday 28 February 2010 02:15:45 Hamish wrote: > John Tate wrote: > > and then patched (r.patch) them all together. The patching should > > average out any differences. > > r.patch doesn't average, it uses the cell from the first-listed raster > map which contains a non-NULL cell. Later-listed rasters fill in the gaps > until there are no more gaps or no more maps. r.series will merge > overlapping maps using an average though.
Yeah, my mistake, again! Keep confusing those two. > > I then cropped out each 1km tile (1000x1000). > > This was done so that the 1km tiles could be combined for specific > > areas by different people (e.g. only a 4kmsq area for academic 'a' or a > > 6kmsq area 2km away for academic 'b'). > > why not just use g.region for that? Interoperability. So they can be used in ArcGIS, MapInfo, IDRISI and TAS by various people (after export as ESRI Grid). > Nick Cahill wrote: > > I was never able to get the parameters right in *.surf.rst, and > > processing times were very long. > > True & true. "auto-tune" has been a wish for a while. it probably would > take a while to run though. maybe the tips on the RST Spline Surfaces > wiki page along with the ones on the main help page can be useful? > The results can be very nice once you get it tuned right though. Nice script here for cross validation: http://lists.osgeo.org/pipermail/grass-user/2007-May/039530.html I used a smaller area, e.g. 100x100 cell area, that is representative of the terrain to speed things up. John _______________________________________________ grass-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-user
