Am 24.08.2010 13:38, schrieb Emilie Laffray: > One possibility would be to add GEOS to osm2pgsql and check the validity > of the polygon in the first place in osm2pgsql. osm2pgsql allows invalid geometries because Mapnik is able to render them. I'd suggest using a trigger that updates a valid column, each time a geometry is changes. Peter