On Mon, May 28, 2012 at 04:19:01PM -0400, Stephen Woodbridge wrote: > On 5/28/2012 3:58 PM, Sandro Santilli wrote: > >On Mon, May 28, 2012 at 02:50:43PM +0200, Michiel J. van Heek wrote:
> >>If we want to handle these kind of > >>cases automatically, the easiest way would be to removed the > >>islands, but I don't like that idea, because some islands may be > >>very big, like the arctic islands of Canada. It is like removing > >>Great Britain from the map. :-) > > > >One way would be to split the edge introducing nodes making it > >harder for each sub-edge to collide to anything. I wonder how > >finding such new nodes could be automated. But we're running too > >much. Zoom on the Brazil coast first, and extrapolate the actual > >error message. Oh, note that running a second time might give you > >more successes, so worth reaching a "stable state" before going > >on. > > If you can detect that an edge collides with another polygon, then > you could take the the points where the edge intersects the polygon > an project them back onto the original edge and split the edge at > those projected points. > > But I'm not sure that helps anything because making it harder does > not insure success. The ST_ChangeEdgeGeom _always_ checks for collision, and the SimplifyEdgeGeom is already based on a probability of success so not a big problem to add some more heuristic steps (IMHO). --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
