Even, Does this approach provide a significant performance increment comparing to the search ellipse option in the inverse distance algorithm?
When I've been recently playing with gdal_grid I could gain further increment by reducing the number of the floating point operations in the inner loop of the algorithm (see GDALGridInverseDistanceToAPowerNoSearch for example), like: 1. Getting out the dfSmoothing * dfSmoothing multiplication from the loop 2. In case when dfPower = 2 we could save using of sqrt and pow at all. 3. Replace CPLIsEqual with a faster approach It must be noted that I had no chance to rely on the assumption that the distant points doesn't affect the value of the result, especially when the points are based on non-geograpic related quantities. Best regards, Tamas 2008/10/31 Even Rouault <[EMAIL PROTECTED]>: > Ari, > > the slowness of gdal_grid when fed with a big number of point features is a > known issue. See ticket #2411. I had attached a patch to speed up the > process. You could give it a try. > > Le Friday 31 October 2008 08:09:11 Ari Jolma, vous avez écrit : >> I'm doing some laser scanning data -> geotiff interpolations and I'm >> finding that they take some time - the current run has been going on for >> ~20 hours now. >> >> The current run is for a 3 by 2 kilometer area, which I'm interpolating >> into a raster with 1 m x 1 m cells. The data is in PostGIS but it >> shouldn't matter: >> >> gdal_grid -a invdist:radius1=10:radius2=10 -txe 3350505 3353786 -tye >> 6692068 6694105 -outsize 3281 2037 -of GTiff -ot Float32 -l nummela >> PG:dbname=nummela nummela.tiff >> Grid data type is "Float32" >> Grid size = (3281 2037). >> Corner coordinates = (3350504.500000 6694105.500000)-(3353786.500000 >> 6692067.500000). >> Grid cell size = (1.000000 1.000000). >> Source point count = 2588809. >> Algorithm name: "invdist". >> Options are >> "power=2.000000:smoothing=0.000000:radius1=10.000000:radius2=10.000000:angl >>e=0.000000:max_points=0:min_points=0:nodata=0.000000" >> >> Any ideas how to make things faster? I did a interpolation to 2 m x 2 m >> raster earlier, which was faster but not very fast either. >> >> Best regards, >> >> Ari >> >> _______________________________________________ >> gdal-dev mailing list >> [email protected] >> http://lists.osgeo.org/mailman/listinfo/gdal-dev > > > _______________________________________________ > gdal-dev mailing list > [email protected] > http://lists.osgeo.org/mailman/listinfo/gdal-dev > _______________________________________________ gdal-dev mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/gdal-dev
