[GRASS-dev] Re: [GRASS GIS] #831: v.category options sum, del, and add do nothing

[GRASS GIS]

#831: v.category options sum, del, and add do nothing
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  Reporter:  isaacullah   |       Owner:  grass-dev at lists.osgeo.org
      Type:  enhancement  |      Status:  reopened                 
  Priority:  major        |   Milestone:  7.0.0                    
 Component:  Vector       |     Version:  svn-develbranch6         
Resolution:               |    Keywords:  v.category               
  Platform:  All          |         Cpu:  All                      
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Comment (by martinl):

 Replying to [comment:4 cmbarton]:
 > This is worth keeping open as an enhancement request rather than a
 defect. v.category dates to an era when vectors did not routinely have
 attribute tables, but only cat and label values like rasters.

 v.category is dedicated for modifying category values in 'coor' (geometry)
 file, it's not touching attribute data.

 > For vectors with attribute tables, v.category becomes highly
 problematic. If it alters the cat values without altering the
 corresponding cat values in the associated attribute table, all links
 between the vector objects and their attribute data are irretrievably lost
 (or lost with out a great amount of work to retrieve them).

 Use `v.to.db option=cat` to add new records to attribute table.

 > My suggestion is to add a flag that will allow v.category to
 simultaneously change the cat value in the vector AND the corresponding
 cat in the linked attribute table of same layer.

 v.category should do one thing - to manage layer/categories in geometry
 file.

 > Because this enhancement request is a change in functionality, I've also
 bumped this to milestone 7.0

 I would not incline to modify v.category in this way.

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Ticket URL: <http://trac.osgeo.org/grass/ticket/831#comment:5>
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