Hi, Finally the ST_Buffer(geom, 0.0) solution has worked fine when applied to the input polygons.
Didier Le 20 mai 2010 à 12:14, didier peeters a écrit : > Hello Nicolas, > > Thanks for this quick and useful answer. > When I run the ST_IsValidReason on the rings it surprisingly doesn't find any > error but when I run it on the original polygon layer I get errors like "Ring > Self-intersection[-2.14772 42.5812]" which is what I expected. > > So I will try to find a solution on the mailing list history or maybe find a > workaround. > > Didier > > > Le 19 mai 2010 à 10:51, Nicolas Ribot a écrit : > >>> Hi everybody, >>> >>> >>> >>> I'm a postgis new user and I would like to submit here a problem I >>> encounter. Here's what I do : >>> >>> from a polygon layer I merge some of them (with ST_UNION) into bigger ones >>> according to an attribute value, then I make an exterior ring (with >>> ST_Collect(ST_ExteriorRing())) around these and then I fill these rings >>> (with ST_Contains) with all the original polygon that are inside ( I do >>> this to have a coherent area without the holes I would have otherwise >>> because of some data particularities). >>> >>> All this works very fine for 99.9 % of the polygons but fails on filling >>> the rings for a few of them. When I look at these I see that they have a >>> loop which is a probably due to a wrong geometry in the original polygons. >>> >>> Does any of you know how to deal with this ? >>> >>> Thanks for your help >>> >> >> Hi, >> You should first check the geometry validity (st_isvalid, >> st_isValidReason) and isolate invalid geometries to correct them >> Some "tricks" can correct them automagically (st_buffer(geom, 0.0) for >> instance) and some programs can help you identifiy invalid geometries >> (Jump for instance, with its validation plugin). >> Mailing list contains useful hints on how to correct invalid geometries. >> >> HTH >> >> Nicolas >> _______________________________________________ >> postgis-users mailing list >> postgis-users@postgis.refractions.net >> http://postgis.refractions.net/mailman/listinfo/postgis-users > > _______________________________________________ > postgis-users mailing list > postgis-users@postgis.refractions.net > http://postgis.refractions.net/mailman/listinfo/postgis-users _______________________________________________ postgis-users mailing list postgis-users@postgis.refractions.net http://postgis.refractions.net/mailman/listinfo/postgis-users
