[GRASS-dev] Re: [GRASS GIS] #957: v.voronoi has extra lines in output

GRASS GIS trac at osgeo.org
Tue Sep 20 05:48:43 EDT 2011


#957: v.voronoi has extra lines in output
--------------------+-------------------------------------------------------
 Reporter:  helena  |       Owner:  grass-dev@…              
     Type:  defect  |      Status:  new                      
 Priority:  major   |   Milestone:  6.4.2                    
Component:  Vector  |     Version:  svn-develbranch6         
 Keywords:          |    Platform:  All                      
      Cpu:  All     |  
--------------------+-------------------------------------------------------

Comment(by mlennert):

 Replying to [comment:9 mmetz]:
 > Replying to [comment:8 mlennert]:
 > >
 > > g.region vect=precip_30ynormals
 > > v.voronoi in=precip_30ynormals out=precip_voronoi
 > >
 > > still gives me a polygon containing two points (39 and 82 - see
 bug_voronoi3.png)
 > >
 > The output is correct, no duplicate centroids. I guess in the screenshot
 you have overlaid precip_30ynormals and not the centroids of
 precip_voronoi.

 Yes, sorry for not being clear.

 >
 > The reason why point 82 (and point 112) is missing is that even though
 g.region vect=precip_30ynormals does set the region extents exactly to the
 vector extents, the extents are stored with insufficient precision in
 WIND:
 {{{
 > region north: 306221.83019368
 > vector north: 306221.830193683563
 >
 > region south: 27606.895351356
 > vector south: 27606.895351000000
 >
 > region east: 917004.82916485
 > vector east: 917004.829164845869
 >
 > region west: 151768.56824561
 > vector west: 151768.568245610630
 }}}
 >
 > which in this case causes two points to be excluded.

 Yes, that was it.

 g.region vect=precip_30ynormals res=1 -a

 does the trick for me.

 Should the precision in the WIND file be increased ? Or the value of
 GRASS_EPSILON to take into account the lesser precision in WIND ?

 Moritz

-- 
Ticket URL: <http://trac.osgeo.org/grass/ticket/957#comment:10>
GRASS GIS <http://grass.osgeo.org>



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