[GRASS-dev] [GRASS GIS] #2358: Strange behaviour with v.net on GRASS GIS 7

[GRASS GIS]

#2358: Strange behaviour with v.net on GRASS GIS 7
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  Reporter:  lluis    |      Owner:  grass-dev@…
      Type:  defect   |     Status:  closed
  Priority:  normal   |  Milestone:  7.0.0
 Component:  Vector   |    Version:  svn-releasebranch70
Resolution:  wontfix  |   Keywords:  Ubuntu 14.04, v.net, attributes
       CPU:  x86-64   |   Platform:  Linux
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Changes (by mlennert):

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


Comment:

 Replying to [ticket:2358 lluis]:
 > Hi,
 >
 > I'm working with GRASS GIS 7.0.0svn (r59969) on Ubuntu 14.04 LTS and I'm
 experiencing a strange behaviour when using v.net. I have set of nodes
 that I want to connect to a collection of streets on a network.
 >
 > When I execute "v.net streets points=libraries out=net op=connect
 thresh=150" on GRASS GIS 6.4.4, the new arc(s)/line(s) that connect the
 points to the network, inherit all the attributes (even the 'cat' value)
 of the pre-existing arcs. But, when I execute the same command on GRASS
 GIS 7.0.0 that expected behaviour doesn't take place. The new
 arc(s)/line(s) generated with GRASS 7 doesn't have attributes, a new cat
 value is generated for each new line but they doesn't appear on the
 attribute table...

 This is not a bug, but a feature, although maybe not documented enough.
 The previous behaviour could be considered a bug, as there is no real
 reason to believe that attributes of the line connected to are valid for
 the line created for the connection. This was, therefore, corrected two
 years ago in v.net. Now v.net attributes new, unique, cat values to the
 new arcs, but these values do not have entries in the attribute table.

 The easiest way to add extra lines into the attribute table for these new
 arcs is to use


 {{{
 v.to.db map op=cat
 }}}

 It is then the responsibility of the user to fill in the other attribute
 fields for these new arcs (using v.db.update).

 However, grass7 also provides the new '-s' flag which, instead of creating
 connection arcs, snaps the points to the closest line. In many
 applications this is more realistic then the connection arcs, and it has
 the added value that the points are then on potential paths and thus one
 can calculate centrality indicators for these points.

 I will file an enhancement ticket that proposes to make this behaviour the
 default behaviour, as I believe that this will avoid many headaches for
 many users. In the meantime, I'm closing this bug.

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Ticket URL: <https://trac.osgeo.org/grass/ticket/2358#comment:1>
GRASS GIS <https://grass.osgeo.org>