[geos-devel] [GEOS] #1045: Buffer returns unexpected geometry

[GEOS]

#1045: Buffer returns unexpected geometry
------------------------+--------------------------
 Reporter:  Mike Taves  |      Owner:  geos-devel@…
     Type:  defect      |     Status:  new
 Priority:  major       |  Milestone:
Component:  Default     |    Version:  master
 Severity:  Unassigned  |   Keywords:
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 Take a valid circular Polygon:
 {{{
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
 }}}
 Buffering with -1.047e-13 and 8 quadrant segments returns an unexpected
 collapsed 1-D Polygon (if that's a thing) with zero area:
 {{{
 POLYGON ((30.429740079806265 -0.2475618833526883, 30.429740079806265
 -0.2475618833526937, 30.429740079806265 -0.2475618833526936,
 30.429740079806265 -0.2475618833526911, 30.429740079806265
 -0.2475618833526842, 30.429740079806265 -0.2475618833526821,
 30.429740079806265 -0.247561883352682, 30.429740079806265
 -0.2475618833526883))
 }}}
 JTS has the same behaviour with this specific example.

 Other buffer distances like -1.04e-13 are not an issue with this polygon.
 This is perhaps related (but not identical) to #1032.

-- 
Ticket URL: <https://trac.osgeo.org/geos/ticket/1045>
GEOS <http://trac.osgeo.org/geos>
GEOS (Geometry Engine - Open Source) is a C++ port of the Java Topology Suite (JTS).