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

[PostGIS]

#5401: ST_Difference silently giving us wrong results
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  Reporter:  laopsahl  |      Owner:  pramsey
      Type:  defect    |     Status:  new
  Priority:  medium    |  Milestone:  PostGIS 3.3.4
 Component:  postgis   |    Version:  3.3.x
Resolution:            |   Keywords:
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Comment (by laopsahl):

 Replying to [comment:3 strk]:
 > The shown image suggests it's the GEOS heuristic overlay reducing the
 precision of input way too much. What's the output of {{{ SELECT
 postgis_full_version() }}} ?

 Here is an list

 {{{

 --Wrong result db09test
 --POSTGIS="3.2.0 c3e3cc0" [EXTENSION] PGSQL="120"
 GEOS="3.10.1-CAPI-1.16.0" SFCGAL="1.3.7" PROJ="8.2.0" GDAL="GDAL 3.4.0,
 released 2021/11/04" LIBXML="2.9.10" LIBJSON="0.13.1" LIBPROTOBUF="1.3.3"
 WAGYU="0.5.0 (Internal)" TOPOLOGY RASTER
 --ON Postgresql 12
 --result = difference_test_01 sum|9|12374747|72

 --Wrong result localhost
 --POSTGIS="3.2.3 2f97b6c" [EXTENSION] PGSQL="140"
 GEOS="3.11.0-CAPI-1.17.0" PROJ="9.0.1" LIBXML="2.9.14" LIBJSON="0.16"
 LIBPROTOBUF="1.4.1" WAGYU="0.5.0 (Internal)" TOPOLOGY
 --ON Postgresql 14
 --result = difference_test_01 sum|9|12374747|72

 --Wrong result CI
 --POSTGIS="3.3.3 2355e8e" [EXTENSION] PGSQL="120"
 GEOS="3.10.2-CAPI-1.16.0" PROJ="8.2.1" LIBXML="2.9.13" LIBJSON="0.15"
 LIBPROTOBUF="1.3.3" WAGYU="0.5.0 (Internal)" TOPOLOGY
 --ON Postgresql 12, 13 and 14
 --result = difference_test_01 sum|8|11848089|67

 --But it seems to work on a local server by Sandro with lates code from
 source (db01tempdb)
 --POSTGIS="3.4.0dev 3.3.0rc2-958-g4c776d418" [EXTENSION] PGSQL="120"
 GEOS="3.9.1-CAPI-1.14.2" SFCGAL="1.3.7" PROJ="7.2.1" LIBXML="2.9.10"
 LIBJSON="0.13.1" LIBPROTOBUF="1.3.3" WAGYU="0.5.0 (Internal)" TOPOLOGY
 --ON Postgresql 12
 --result = difference_test_01 sum|1551|15799749|412840


 }}}
-- 
Ticket URL: <https://trac.osgeo.org/postgis/ticket/5401#comment:6>
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