[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):

 Manual:

 "Each path consist of several lines. If a line is on the shortest path
 from a point then the category of this point is assigned to the line. Note
 that every line may contain more than one category value since a single
 line may be on the shortest path for more than one from feature."

 That means lines are copied directly from input to output, line directions
 are not adjusted and lines are not merged to unique paths for each `from`
 category.

 Unfortunately, the paths as reported by v.net.distance (irrespective of
 the direction) are wrong: the shortest path from 7779 to 7780 should take
 the long route, and the shortest path from 7780 to 7779 should take the
 short route. Fixing this bug would require a new function in
 lib/vector/neta. Hopefully the dglib interface allows for an easy solution
 to provide an inverse to
 lib/vector/neta/path.c:NetA_distance_from_points().

 This ticket should be closed and a new ticket should be opened that
 v.net.distance calculates paths in reverse (from to to from instead of
 from from to to).

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Ticket URL: <http://trac.osgeo.org/grass/ticket/2936#comment:1>
GRASS GIS <https://grass.osgeo.org>