Thanks Martin, I was thinking it might be something like that.
cheers Ben On 16/02/2010, at 8:40 , Martin Davis wrote: > JTS/GEOS can sometimes does some internal transformation of geometries to > try and overcome robustness errors. So the coordinates in TopologyException > error messages may not always correspond to the coordinate system of the > input geometries. > > Ben Madin wrote: >> G'day all, >> >> I have a topology exception with a file I clean up with GRASS and exported >> back into PostGIS, which I discovered when I tried to merge provinces into >> countries: >> >> CREATE TABLE new_country AS SELECT country::varchar(3), st_union(the_geom) >> as the_geom >> FROM new_prov >> GROUP BY country; >> >> NOTICE: TopologyException: found non-noded intersection between LINESTRING >> (-0.204257 0.999226, -0.204257 0.99858) and LINESTRING (-0.204257 0.995743, >> -0.204257 0.999226) at -0.204257 0.999226 >> >> There is obviously information here on where the problem lies, but my entire >> project is in Lat / Long (EPSG:4326) in South East Asia, so I'm guessing >> this is not (nor is it on a unit square) >> >> So : >> >> How does the coordinates returned by the error relate to my geometry? or >> What do they mean? Can I use this information to find the problem part of >> the geometry. >> >> (as an aside, changing the query to st_union(st_buffer(the_geom,0)) let it >> through (and it works as I wanted) >> >> cheers >> >> Ben >> _______________________________________________ >> postgis-users mailing list >> [email protected] >> http://postgis.refractions.net/mailman/listinfo/postgis-users >> >> > > -- > Martin Davis > Senior Technical Architect > Refractions Research, Inc. > (250) 383-3022 > > _______________________________________________ > 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
