[GRASS-dev] [GRASS GIS] #2936: v.net.distance: wrong directions in one-way streets

[GRASS GIS]

#2936: v.net.distance: wrong directions in one-way streets
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  Reporter:  mlennert    |      Owner:  grass-dev@…
      Type:  defect      |     Status:  new
  Priority:  normal      |  Milestone:  7.0.4
 Component:  Vector      |    Version:  svn-trunk
Resolution:              |   Keywords:  v.net.distance network one-way
       CPU:              |  direction
  Unspecified            |   Platform:  Unspecified
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Comment (by mmetz):

 Replying to [comment:4 mlennert]:
 > Replying to [comment:3 mmetz]:
 >
 > I don't have a problem with line directions remaining as in the
 original.

 I have, so I adjusted line directions to match path directions in r67990.
 v.net.path also adjusts line directions to match path directions.
 >
 > >Correct paths are created with trunk r67984,5.
 >
 > Thanks, works great now !
 >
 >
 > > There is also a new -l flag that produces a single line for each path
 with appropriate line direction.
 >
 > Nice. Just one remark: the line seems to only have a category value in
 layer 2, not in layer 1. Is that intended ?

 Not really intended, paths got all categories of their from feature.
 Changed in r67990 to match the default output of paths consisting of
 different lines. I got distracted by the directed graph library which is
 only slightly less difficult to read than the wxpython GUI code base.

 AFAICT, v.net.distance is now the only module using version 2 directed
 graphs. All other v.net.* modules use version 1 directed graphs. The
 directed graph library offers to create graphs (networks) of version 1, 2,
 and 3. Only version 1 graphs have been used and tested since 2003 within
 GRASS GIS.

 I have introduced this bug indirectly myself by adding options to define
 different forward and backward costs to lines, without updating the
 underlying code base (GSoC project 2009 by Daniel Bundala, impressive code
 quality and thorough understanding of network analysis).

 It is not clear to me why v.net.distance copies 'from' features to the
 output but not 'to' features. Any opinion?

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Ticket URL: <https://trac.osgeo.org/grass/ticket/2936#comment:5>
GRASS GIS <https://grass.osgeo.org>