[geos-devel] [GEOS] #380: Buffer(Geometry, 0) deletes part of the polygon

[GEOS]

#380: Buffer(Geometry,0) deletes part of the polygon
------------------------+---------------------------------------------------
 Reporter:  jaapdekker  |       Owner:  geos-devel@…              
     Type:  defect      |      Status:  new                       
 Priority:  minor       |   Milestone:                            
Component:  Default     |     Version:  3.2.0                     
 Severity:  Unassigned  |    Keywords:                            
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 Using buffer(Geometry,0) to fix wrong polygons is not always working OK
 The polygon that I try to fix has a Self-intersection at or near point -70
 57

 calling
 {{{
 Select AsText(Buffer(MPolyFromText('MULTIPOLYGON(((-66 58,-66 59,-64
 58,-65 58,-66 58),(-70 57,-66 57,-66 58,-68 58,-68 57,-70 57)),((-70
 58,-70 57,-72 57,-72 59,-71 59,-71 58,-70 58)))'),0));
 }}}
 gives as result
 {{{
 MULTIPOLYGON(((-70 57, -72 57, -72 59, -71 59, -71 58, -70 58, -70 57)),
 ((-66 58, -66 59, -64 58, -65 58, -66 58)))
 }}}
 it is missing the part
 {{{
  (-70 57,-66 57,-66 58,-68 58,-68 57,-70 57)
 }}}
 in the output

 I'm Using Spatialite version 2.4rc3 wich is using geos version
 3.2.2-CAPI-1.6.2

-- 
Ticket URL: <http://trac.osgeo.org/geos/ticket/380>
GEOS <http://geos.refractions.net/>
GEOS (Geometry Engine - Open Source) is a C++ port of the Java Topology Suite (JTS).