[GRASS-dev] Re: [GRASS GIS] #517: v.net.iso loses or does not create a database connection for resulting vector map

GRASS GIS trac at osgeo.org
Fri Mar 6 11:41:35 EST 2009

#517: v.net.iso loses or does not create a database connection for resulting
vector map
  Reporter:  effilc36     |       Owner:  grass-dev at lists.osgeo.org
      Type:  enhancement  |      Status:  new                      
  Priority:  minor        |   Milestone:  7.0.0                    
 Component:  default      |     Version:  svn-trunk                
Resolution:               |    Keywords:  v.net.iso                
  Platform:  All          |         Cpu:  All                      
Changes (by mlennert):

  * platform:  MacOSX => All
  * version:  6.4.0 RCs => svn-trunk
  * type:  defect => enhancement
  * cpu:  OSX/Intel => All
  * milestone:  6.4.0 => 7.0.0


 Reclassifying this as a wish instead of a bug since this is a feature of
 the current version of v.net.iso: all line segments are given the category
 number of the distance class they belong to. Thus they cannot be linked to
 the table of the original input file, as the segment identifiers have
 changed and do not correspond to the original attribute table key field

 However, I do agree that it might be desirable to implement (some of) the

 1) at least create an attribute field containing the min and max distances
 of the class. Otherwise, you might forget which distances you used to
 create the map and then the cat values are useless for anything else but
 ordinal logic.

 2) keep the old category values of the input map and create a new column
 in the table in which you enter the distance class (preferrably in the
 form "min-max") for each line segment. This way one could connect to the
 table of the input map if so desired

 3) add a flag which would allow to do 2) by updating the table of the
 input map instead of creating a new map. No need really to use up disk
 space for a map which only contains distance classes if you can just as
 easily integrate them into the existing attribute table. Even more
 relevant now that Markus' work allows to use quite large networks.


Ticket URL: <http://trac.osgeo.org/grass/ticket/517#comment:1>
GRASS GIS <http://grass.osgeo.org>

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