[GRASS-dev] [GRASS GIS] #2007: v.to.db azimuth direction

GRASS GIS trac at osgeo.org
Sat Jun 15 16:24:30 PDT 2013

#2007: v.to.db azimuth direction
 Reporter:  davidinosauro  |       Owner:  grass-dev@…              
     Type:  defect         |      Status:  new                      
 Priority:  trivial        |   Milestone:  6.4.4                    
Component:  Docs           |     Version:  unspecified              
 Keywords:  v.to.db        |    Platform:  Unspecified              
      Cpu:  Unspecified    |  

Comment(by hamish):

 v.to.db is a bit backward in this respect, elsewhere in grass the
 convention is always cartesian (theta CCW from the +x axis) not nautical
 (degrees CW from north). Without saying that one way is more appropriate
 than the other, I believe that for consistency v.to.db should be changed
 in trunk to match the rest.

 I've been slowly adding options to modules to allow both, but default to

       aspect_type   Direction map aspect type
                     options: cartesian,compass
                     default: cartesian

 where `cartesian = 90 - compass` and vice versa. you can do that in
 db.execute to add the alternate convention into a new column.

 and if v.to.db+azimuth doesn't already error-out in a lat/lon location, it
 should. (even if using geodesics, great circle azimuth has two diff't
 answers depending on which endpoint you use, and it transitions along the

 patches for docs always welcome,

Ticket URL: <http://trac.osgeo.org/grass/ticket/2007#comment:2>
GRASS GIS <http://grass.osgeo.org>

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