[GRASS-dev] [GRASS GIS] #1798: all relevant vector modules should have cats and where parameters

[GRASS GIS]

#1798: all relevant vector modules should have cats and where parameters
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 Reporter:  mlennert              |       Owner:  grass-dev@…              
     Type:  enhancement           |      Status:  new                      
 Priority:  normal                |   Milestone:  7.0.0                    
Component:  Vector                |     Version:  svn-trunk                
 Keywords:  where cats parameter  |    Platform:  Unspecified              
      Cpu:  Unspecified           |  
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Comment(by glynn):

 Replying to [comment:6 mmetz]:

 > The advantage of a virtual map over using v.extract to get a "permanent"
 selection by cats/where is not clear to me
 Disk usage. A virtual map wouldn't require an extra copy of the
 coordinates and topology.

 > because the result of v.extract can be processed faster than a virtual
 map.
 In the simplest case, a virtual map shouldn't be any slower than providing
 cats=/where= on the command line; they both do the same thing. There may
 be a difference in the case where you use where= when creating the virtual
 map and again when processing it (i.e. you'd have to "compose" the where=
 queries).

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Ticket URL: <http://trac.osgeo.org/grass/ticket/1798#comment:8>
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