Thanks Markus. I'm out of office, but I will try your solution as soon as possible.
2009/2/20 Markus Metz <markus.metz.gisw...@googlemail.com>: > Hi Giovanni, > > could you please check out > svn checkout https://svn.osgeo.org/grass/grass-addons/raster/r.univar2.zonal > and let me know if the results and the speed are ok? > > r.univar2.zonal does zonal statistics if I understood the concept all right. > You have to give a zoning map as input. That would be in your case the > rasterized vector areas. The output can be very long, as in your case, so I > added an option to dump the stats in a file, that way it's easier to > scrutinize. > In my tests, the stats were identical to r.univar2 in develbranch_6, only > that I had to run r.univar2.zonal only once and not several times. This > r.univar2.zonal is not polished: 3D support is missing and the output is not > shell style although it should be, no idea why not. I would like to leave > the polishing to the experts. > > I haven't added an entry in wiki addons, because I don't know if this is an > unpolished gem or unnecessary with your current solution or a pile of trash > (well, not completely trash, results are at least identical to r.univar2). > > Regards, > > Markus M > > > G. Allegri wrote: >> >> The rasterizing method gives comparable performances to ArcGIS. I >> confirm that it does the same. >> The bottleneck is the r.univar limitation to CELL. I have to >> investigate why, as it is based on r.stats which works with >> DCELL/FCELL too >> >> The final join would be an improvement respect to Zonal Statistics in >> ArcGIS which simply produce a dbf with OIDs from polygon IDs but >> doesn't merge it into the original vectorial. >> >> >> 2009/2/19 Markus Metz <markus.metz.gisw...@googlemail.com>: >> >>> >>> Markus Neteler wrote: >>> >>>> >>>> On Thu, Feb 19, 2009 at 2:20 PM, G. Allegri <gioha...@gmail.com> wrote: >>>> >>>> >>>>> >>>>> Thanks for the ideas. >>>>> I've just tried Starspan but it's performance is still too slow. I've >>>>> let it run for 15 minutes... >>>>> >>>>> >>>> >>>> Can you please try GRASS 7? >>>> grass70/scripts/v.rast.stats/v.rast.stats.py >>>> >>>> >>> >>> grass70/scripts/v.rast.stats/v.rast.stats.py also uses r.mapcalc in every >>> pass: >>> >>> for i in cats: >>> ... >>> grass.mapcalc("MASK = if(...) >>> >>> if v.rast.stats is faster in grass7, then probably because of improved >>> raster libs. A speed increase from >5 hours to 40 seconds is unlikely >>> since >>> grass.mapcalc is still called 1793 times (assuming each area has a unique >>> category) for a region with 4415x6632 cells... >>> >>> >>> >> >> > _______________________________________________ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user