[QGIS-trac] Re: [Quantum GIS] #3184: Strange behavior of dissolve tool

[Quantum GIS]

#3184: Strange behavior of dissolve tool
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        Reporter:  dr                                |         Owner:  cfarmer      
            Type:  bug                               |        Status:  closed       
        Priority:  major: does not work as expected  |     Milestone:  Version 1.6.0
       Component:  MapCanvas                         |       Version:  Trunk        
      Resolution:  duplicate                         |      Keywords:               
Platform_version:                                    |      Platform:  All          
        Must_fix:  Yes                               |   Status_info:  0            
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Changes (by cfarmer):

  * status:  new => closed
  * resolution:  => duplicate


Comment:

 This is really a duplicate of #3126, and appears to boil down to the
 precision of the layers, rather than an actual problem with the dissolve
 tool. Unlike Arc*, QGIS (and GEOS) do not use any tolerance when unioning
 geometries (which is what the dissolve tool uses). As such, layers with
 'nearly' identical geometries will not be dissolved as if they were
 identical. A solution to this is to use the simplify tool beforehand, or
 to reduce the precision of your vector layers.

 I am going to close this one as duplicate.

 Carson

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Ticket URL: <https://trac.osgeo.org/qgis/ticket/3184#comment:3>
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