> 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
