[postgis-users] side location conflict in GeomUnion function

Hisaji Ono hi_ono2001 at ybb.ne.jp
Thu Nov 13 21:30:03 PST 2003

Thank you very much, Paul.

 I've resolved this problem using "magical" Buffer function as follows.

select GeomUnion(Buffer(the_geom,0))  from kagawa group by  y2000;

 But island polygons were vanished, if these necessary, I should regenerate
these ones using Difference function.

> Have you checked that all your geometries are valid first?
> select * from geomtable where not isvalid(the_geom);
> invalid geometries are the #1 cause of topology failures.

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