[postgis-tickets] [PostGIS] #3341: Serious rounding issues

[PostGIS]

#3341: Serious rounding issues
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 Reporter:  postgispaul  |      Owner:  pramsey
     Type:  defect       |     Status:  new
 Priority:  medium       |  Milestone:
Component:  postgis      |    Version:  2.2.x
 Keywords:               |
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 I have 3 polygons (in 4326 projection), and when I calculate st_difference
 on those, there appears to be great rounding-issues.

 Query which results in erroneous polygon:
 select st_difference(t1.geom,st_collect(t2.geom))
 from error as t1
 join error t2 on true
 where t1.id=1 and t2.id in (600,1351)
 group by t1.geom

 Screenshot is in attachment.
 Green filled polygon is the result of said query, black outlines are the
 contours of the polygons in the table.

 Table should be filled with the contents of polygons.txt from attachment


 Versions:
 "POSTGIS="2.2.0 r14208" GEOS="3.5.0-CAPI-1.9.0 r4090" PROJ="Rel. 4.9.1, 04
 March 2015" GDAL="GDAL 2.0.1, released 2015/09/15 GDAL_DATA not found"
 LIBXML="2.7.8" LIBJSON="0.12" TOPOLOGY RASTER"
 "PostgreSQL 9.4.1, compiled by Visual C++ build 1800, 64-bit"

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Ticket URL: <http://trac.osgeo.org/postgis/ticket/3341>
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