[geos-devel] Re: [GEOS] #527: Union and UnaryUnion both fail at correctly node input lines

[GEOS]

#527: Union and UnaryUnion both fail at correctly node input lines
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 Reporter:  strk        |       Owner:  geos-devel@…              
     Type:  defect      |      Status:  new                       
 Priority:  major       |   Milestone:  3.3.4                     
Component:  Default     |     Version:  3.3.3                     
 Severity:  Unassigned  |    Keywords:                            
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Comment(by strk):

 Further analysis: the first attempt at running the union overlay op fails
 the internal noding validator step:
 {{{
 EdgeNodingValidator found noding invalid: TopologyException: found non-
 noded intersection between LINESTRING (1.72506e+06 4.81909e+06,
 1.72506e+06 4.81909e+06) and LINESTRING (1.72506e+06 4.81909e+06,
 1.72506e+06 4.81909e+06) at 1725064.1365604457 4819094.70235069
 }}}

 So SnapIfNeededOverlayOp switches on snapping, which seems to pass the
 check:
 {{{
 EdgeNodingValidator accepted the noding
 }}}

 Now it'd be interesting to see _why_ the internal edge noding validator
 passes while our own checking fails it !

-- 
Ticket URL: <http://trac.osgeo.org/geos/ticket/527#comment:5>
GEOS <http://geos.refractions.net/>
GEOS (Geometry Engine - Open Source) is a C++ port of the Java Topology Suite (JTS).