On Sun, Dec 28, 2014 at 8:04 PM, Fábio Dias <[email protected]> wrote: > Hello all, > > Context: I've loaded some shp files into postgis, containing > information over the amazon forest. For reference, the sql script has > around 6Gb.
How many polygons do you have there approximately? > Problem: I managed do import, clean and dissolve properly, but when I > run the generalization, by my estimates, it would take almost an year > to complete. This will also depend on the generalization method you selected. > I also noticed that neither grass nor postgis are capable of parallel > processing... Yeah, hot topic for 2015 :-) Indeed, worth a thesis in my view! > Question: Am I using the correct tool for that? Is there a way to > speed up the processing? > > For reference, the commands i've used (grass70, beta4, 22 dez 2014): (Glad you use beta4, so we have a recent code base to check.) > v.in.ogr -e --verbose input="pg:host=localhost (...)" layer=ap10 > output=ap10 snap=1e-6 --> Please tell us how many polygons or lines the layer "ap10" contains. > v.clean -c --verbose input=ap10 output=ap10c tool=bpol,break,rmsa type=line --> Not sure but should type be "boundary" or "line"? > v.dissolve --verbose input=ap10c column=tc_2010 output=ap10d --overwrite --> How many polygons does "ap10d" contain? > Try #1 ) v.generalize --verbose --overwrite input=ap10d output=ap10r > method=reduction threshold=0.00025 --overwrite > Try #2 ) v.generalize --verbose --overwrite input=ap10d output=ap10g > method=douglas threshold=0.00025 --overwrite I suppose that method=douglas is faster that method=reduction? What is the projection you are working with? Given the threshold and assuming LatLong, I get a short distance: GRASS 7.1.svn (latlong):~ > g.region -g res=0.00025 -a n=4.15 s=-16.369 w=-76.23975 e=-45.1125 nsres=0.00025 ewres=0.00025 ... GRASS 7.1.svn (latlong):~ > g.region -m... nsres=27.64959657 ewres=27.21883498 ... Probably you want to try a larger threshold first? Markus _______________________________________________ grass-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-user
