Sorry if my answer is a bit out of the scope of Grass : from time to time I use OpenJump GIS. For this type of task (don't ask me why) it's incredibly faster. Maybe any of you could explain this difference ?
VB Le vendredi 17 août 2007 à 17:21 +1200, Hamish a écrit : > > Mark wrote: > > > Is the best way to clip data to use the v.overlay command with the > > > "and" operator? > > > > > > it works great, but seems quite slow on larger datasets. > > > Additionally as an example, if i have topographic contour lines, and > > > i want to clip them to a polygon, and only want the topo line > > > attributes (elevation) outputted, is there a way to do this? Is > > > there another way to clip line data to within a polygon that might > > > be a bit faster? > > > Hamish: > > run v.select, then v.overlay. That way the intensive v.overlay > > operation only happens for relevant vector features. Then it will > > speed up hugely. > > > > I wonder if v.select functionality could be built into v.overlay as a > > preprocessing step? > > > (see Radim's doc/vector/TODO in the source code; maybe splitting long > boundaries helps too?) > > > Hamish > > _______________________________________________ > grassuser mailing list > [email protected] > http://grass.itc.it/mailman/listinfo/grassuser > _______________________________________________ grassuser mailing list [email protected] http://grass.itc.it/mailman/listinfo/grassuser
