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

[GEOS]

#380: Buffer(Geometry,0) deletes part of the polygon [JTS affected too]
-------------------------+--------------------------------------------------
 Reporter:  jaapdekker   |       Owner:  geos-devel@…              
     Type:  enhancement  |      Status:  new                       
 Priority:  minor        |   Milestone:  GEOS Future               
Component:  Default      |     Version:  3.2.0                     
 Severity:  Unassigned   |    Keywords:                            
-------------------------+--------------------------------------------------

Comment(by corrado9999):

 Please, notice that the input geometry jaapdekker is using is:

 {{{
 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));
 ^^^
 }}}

 and not what I think he meant:

 {{{
 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));
 ^^^^^
 }}}

 I could only test it using the Python bindings of OGR, but with them I
 experienced the same issue reported. If I use instead the new polygon, the
 output is the following:

 {{{
 'MULTIPOLYGON (((-70 57,-72 57,-72 59,-71 59,-71 58,-70 58,-70 57)),((-68
 57,-68 58,-66 58,-66 57,-68 57)),((-66 58,-66 59,-64 58,-65 58,-66 58)))'
 }}}

-- 
Ticket URL: <http://trac.osgeo.org/geos/ticket/380#comment:7>
GEOS <http://geos.refractions.net/>
GEOS (Geometry Engine - Open Source) is a C++ port of the Java Topology Suite (JTS).