[postgis-tickets] [PostGIS] #5401: ST_Difference silently giving us wrong results

PostGIS trac at osgeo.org
Thu Jun 15 08:06:00 PDT 2023


#5401: ST_Difference silently giving us wrong results
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  Reporter:  Lars Aksel Opsahl  |      Owner:  pramsey
      Type:  defect             |     Status:  new
  Priority:  medium             |  Milestone:  PostGIS GEOS
 Component:  postgis            |    Version:
Resolution:                     |   Keywords:
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Comment (by Lars Aksel Opsahl):

 Replying to [comment:17 strk]:
 > Just to complete the picture, the debugging logs continue to the
 precision reduction heuristics which end up with the garbage result.
 Detailed logs are in
 https://github.com/libgeos/geos/issues/924#issuecomment-1593160531
 >
 > It turns out this problem is 2-fold:
 >
 >  1. GEOMETRYCOLLECTION should not be passed to ST_Difference but GEOS
 fails to report this ---> https://github.com/libgeos/geos/issues/925
 >  2. GEOS attempts to still support the operation goes too far --->
 https://github.com/libgeos/geos/issues/924

 Thanks, very nice. I then assume then you have what you need, but if you
 need more we create branch for you on https://gitlab.com/nibioopensource
 /resolve-overlap-and-gap .
-- 
Ticket URL: <https://trac.osgeo.org/postgis/ticket/5401#comment:20>
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