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

Quantum GIS qgis at qgis.org
Mon Nov 8 18:44:12 EST 2010

#3126: Sliver holes remain after dissolve
        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            

Comment(by cfarmer):

 From a relatively quick Googling around, it appears as though GEOS *does
 not* employ any sort of tolerance when performing unions (which is what
 dissolve uses). There was some talk about snap-rounding to fix *some*
 issues with slivers, but this isn't really a sure-fire fix. One way around
 these sorts of issues (similar to snap-rounding) could be to simply round
 off the geometry coordinates at some level. This would likely reduce the
 number of high-precision slivers, but wouldn't get ride of all of them,
 and might not be great in cases where a high level of precision is needed
 (i.e. the distortion might be too large).


Ticket URL: <https://trac.osgeo.org/qgis/ticket/3126#comment:15>
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