Indeed - this ST_SnapToGrid() does the trick - and explains why ST_Polygonize failed. I wonder if there is a way to see these very slight inaccuracies with "ST_AsText()". In my case ST_AsText() only returned three digits after the comma (that's why I assumed the start/end points are actually the same), not the 10 digits you mention below. Is there any trick to tell ST_AsText() to be more accurate?
Thanks again, Andreas > This is not a bug. It looks like your linestrings are not properly noded. > > IE. on your line in question, the end node is POINT (697787.741 > 247263.451), but the other two lines are noded at POINT > (697787.7410000002 247263.451). > > Try using snaptogrid(). > > SELECT geom AS the_geom > FROM ST_Dump(( > SELECT ST_Polygonize(ST_SnapToGrid(the_geom, 0.001)) AS geom > FROM admin.plz)); > > Cheers, > > ------------- > Kevin Neufeld > Software Developer > Refractions Research Inc. > 300-1207 Douglas St. > Victoria, B.C., V8W 2E7 > > Phone: (250) 383-3022 > Email: [EMAIL PROTECTED] > > > > Andreas Neumann wrote: >> Hello, >> >> I have a linenetwork with 15 LINESTRING() elements. I am using >> ST_POLYGONIZE() to create new POLYGON() elements. I'd expect to get 6 >> polygons, but ST_POLYGONIZE() creates only 5 polygons. To make sure that >> my data is ok, I selected all start and endpoints of the LINESTRING()s >> and >> made sure that every start/endpoint of a LINESTRING() has two >> counterparts, which is the case. >> >> This looks like a bug to me. I would appreciate if someone else could a >> look at my data. Attached is the dump of the table and a screenshot of >> the >> line-network. If you load the dump, you might want to replace the owners >> with your own userid. In the screenshot, one line is marked as green. >> This >> is the line that is ignored by the ST_Polygonize() command. >> >> I used >> SELECT geom AS the_geom FROM ST_Dump((SELECT ST_Polygonize(the_geom) AS >> geom FROM admin.plz)); >> as the SQL query. >> >> I'd appreciate any help on my problem, resp. an answer if this might be >> a >> bug or not. >> >> Thank you, >> Andreas >> >> >> >> ------------------------------------------------------------------------ >> >> ------------------------------------------------------------------------ >> >> _______________________________________________ >> 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 > -- Andreas Neumann Böschacherstrasse 6, CH-8624 Grüt/Gossau, Switzerland Email: [EMAIL PROTECTED], Web: * http://www.carto.net/ (Carto and SVG resources) * http://www.carto.net/neumann/ (personal page) * http://www.svgopen.org/ (SVG Open Conference) * http://www.geofoto.ch/ (Georeferenced Photos of Switzerland) _______________________________________________ postgis-users mailing list [email protected] http://postgis.refractions.net/mailman/listinfo/postgis-users
