Sometimes I get self-intersection problems when projecting data into 2d, it was valid in spherical but becomes self-intersecting in a 2d projection. To see where the problems are run:
select gid from sometable where ST_IsValid(geometry) = 'F'; If that shows any rows, then I run: update sometable set geometry = ST_MakeValid(geometry) where ST_IsValid(geometry) = 'F' On Sat, Nov 26, 2011 at 11:46 AM, Bob and Deb <[email protected]> wrote: > I notice with some self-intersecting polygons, st_buffer() with distance > of 0 can make polygons disappear. > > -Bob > On Nov 26, 2011 2:26 AM, "Sandro Santilli" <[email protected]> wrote: > >> On Sat, Nov 26, 2011 at 09:35:47AM +0200, ahmet temiz wrote: >> >> > Could you give me an idea to solve this problem ? >> > >> > "Ring Self-intersection at or near point 39.0002 37.8181" >> >> Try passing the geoms under st_buffer() with a distance of 0. >> Alternatively, if you can, use ST_MakeValid() found in PostGIS-2.0. >> >> If you feel adventurous you could build a standard topology and >> clean from there. See: >> http://strk.keybit.net/blog/2011/11/21/topology-cleaning-with-postgis/ >> >> --strk; >> >> () Free GIS & Flash consultant/developer >> /\ http://strk.keybit.net/services.html >> _______________________________________________ >> postgis-users mailing list >> [email protected] >> http://postgis.refractions.net/mailman/listinfo/postgis-users >> > > _______________________________________________ > postgis-users mailing list > [email protected] > http://postgis.refractions.net/mailman/listinfo/postgis-users > >
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