[QGIS-trac] Re: [Quantum GIS] #3126: Sliver holes remain after dissolve

[Quantum GIS]

#3126: Sliver holes remain after dissolve
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        Reporter:  gislab                            |         Owner:  jef          
            Type:  bug                               |        Status:  closed       
        Priority:  major: does not work as expected  |     Milestone:  Version 1.6.0
       Component:  Vectors                           |       Version:  Trunk        
      Resolution:  invalid                           |      Keywords:               
Platform_version:                                    |      Platform:  All          
        Must_fix:  No                                |   Status_info:  0            
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Comment(by strk):

 GEOS only employs snaprounding IFF w/out it it could not properly node the
 input, so it's a fallback rather than a feature. The approach is to keep
 as much precision as possible during union operations.

 Starting with GEOS-3.3.0 an entry point for snapping is available in the
 C-Api.
 Not sure it's needed as Qgis might be perfectly capable of doing the
 snapping part itself.

 I guess it might make sense to expose an option in the qgis gui to do some
 snapping/renoding before running an union.

 Mind you: this is not a bug, as the vertices of those slivers are most
 likely _not_ exactly the same, altought they might look like identical
 when converted from binary to decimal representation.

-- 
Ticket URL: <https://trac.osgeo.org/qgis/ticket/3126#comment:16>
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