[GRASS-dev] Re: [GRASS GIS] #425: v.out.ogr: don't use random access to find attributes

[GRASS GIS]

#425: v.out.ogr: don't use random access to find attributes
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  Reporter:  neteler      |       Owner:  grass-dev at lists.osgeo.org
      Type:  enhancement  |      Status:  new                      
  Priority:  major        |   Milestone:  6.5.0                    
 Component:  Vector       |     Version:  unspecified              
Resolution:               |    Keywords:                           
  Platform:  All          |         Cpu:  All                      
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Comment (by mlennert):

 Replying to [ticket:425 neteler]:
 > Moved here from
 http://trac.osgeo.org/grass/browser/grass/trunk/doc/vector/TODO#L250
 >
 > Radim suggested:
 >
 > v.out.ogr is very slow because it is using random access to the
 attributes. It should be rewritten so that all attributes are selected by
 one query, geometry for each attribute can be searched by category index
 (which is fast).

 I've implemented something like this in a long-ago rewrite (never
 committed) of d.vect.chart [1] - see plot.c. It uses db_open_select_cursor
 to access the table in one query and then for each row Vect_cidx_find_all
 to find the geometries associated to the cat value in that row.



 Moritz



 [1] http://lists.osgeo.org/pipermail/grass-dev/2006-October/026624.html

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Ticket URL: <http://trac.osgeo.org/grass/ticket/425#comment:1>
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