On Wed, Apr 11, 2012 at 02:59:41PM +0200, Sandro Santilli wrote: > Alternatively you could still construct the topology with full-precision > edges and then simplify the edges in-place (possibly after a CopyTopology), > using ST_ChangeEdgeGeom. That way the _original_ nodes will remain the same > and you'd be only simplifying the edges connecting them. Beware in this > case that simplification might still introduce topology errors but such > errors would be cought by ST_ChangeEdgeGeom with throwing an exception. > > You may catch the exception to reduce tolerance for a given edge or bypass > all checks by editing the edge_data table directly and cross your fingers :) > ValidateTopology should then tell you what you broke, if you want to fix > manually after the fact.
FYI, I wrote a blog post showcasing this approach (with code): http://strk.keybit.net/blog/2012/04/13/simplifying-a-map-layer-using-postgis-topology/ --strk; ,------o-. | __/ | Delivering high quality PostGIS 2.0 ! | / 2.0 | http://strk.keybit.net - http://vizzuality.com `-o------' _______________________________________________ postgis-users mailing list postgis-users@postgis.refractions.net http://postgis.refractions.net/mailman/listinfo/postgis-users
