Hello, You should also have a look at some functions made by Nicolas Ribot : http://trac.osgeo.org/postgis/wiki/UsersWikiSimplifyPreserveTopology
Topology approach is also described. Hugues. -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Paolo Cavallini Sent: Tuesday, December 10, 2013 7:00 AM To: [email protected] Subject: Re: [postgis-users] Overlapping of polygons withSimplifyPreserveTopology -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Il 10/12/2013 04:49, Luca Morandini ha scritto: > we noticed that, despite the use of ST_SimplifyPreserveTopology, > non-adjacent polygons may overlap; this happens when there is a long > and narrow water body of between them (think of a fiord), but this > body is not itself a polygon. > > To solve this issue we came up with the idea of adding an "universe > polygon"; that is, a polygon that enclose the entire extent of a > table, so that every polygon has a left and right > polygon: would this do the trick ? Hi Luca, you really need to use full topology for this. ST_SimplifyPreserveTopology simply prevents topological errors, it does not guarantee sharing of nodes etc. Good luck. - -- Paolo Cavallini - www.faunalia.eu QGIS & PostGIS courses: http://www.faunalia.eu/training.html -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.15 (GNU/Linux) Comment: Using GnuPG with Icedove - http://www.enigmail.net/ iEYEARECAAYFAlKmreQACgkQ/NedwLUzIr538QCePEiOoGaI2eSq9u8JsCviY77X 0bgAn0BrwdhOY0Ua4hnLmIWE/YdkLon3 =UWZJ -----END PGP SIGNATURE----- _______________________________________________ postgis-users mailing list [email protected] http://lists.osgeo.org/cgi-bin/mailman/listinfo/postgis-users _______________________________________________ postgis-users mailing list [email protected] http://lists.osgeo.org/cgi-bin/mailman/listinfo/postgis-users
