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

[GRASS GIS]

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

 Replying to [comment:16 mmetz]:
 > See comment:13 for a suggestion

 (thanks, I'd missed that)

 > > Therefore it may be a good idea to do the adjustment that
 > > g.region currently does in trunk/general/g.region/main.c#L549
 > > and following lines not only for window.north == window.south
 > > etc. but always, to make sure that all vector features are
 > > really inside the current region?

 By "always" you mean just when used with vect=, right? :)

 The idea to round out by 1/2 a grid cell in each direction seems ok at
 first, but I speculate about what the problems might be:

  - as res= is typically not set with vect=, what happens if original res
 is quite large but vector bbox is very small? you get a big region as a
 result when you wanted one orders of magnitude smaller.

  - what if you have a series of vector points broken up by region (lidar
 1km x 1km chunk files) and want to patch their bboxes together? would you
 be better/worse/no worse than now?


 perhaps it is better to expand by some other proportional amount? like the
 lesser of 1/2 a grid cell, or +/- (n-s)*1e-n ?  (where n=6..15), or +/-
 GRASS_EPSILON and change the WIND file (and thus all other G_format_*())
 to record to useless/impracticable/wasteful precision?
 or hardcode the +/- 0.00000001 with a note that it should match the
 precision in format_double()?


 open to suggestions,
 Hamish

 ps- it is wonderful that this longstanding v.voronoi bug is near to being
 fixed!

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Ticket URL: <http://trac.osgeo.org/grass/ticket/957#comment:17>
GRASS GIS <http://grass.osgeo.org>