[GRASS-dev] [GRASS GIS] #2637: Get direction raster in clockwise degrees starting from the North

[GRASS GIS]

#2637: Get direction raster in clockwise degrees starting from the North
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 Reporter:  cgravelm     |       Owner:  grass-dev@…              
     Type:  enhancement  |      Status:  new                      
 Priority:  normal       |   Milestone:  7.0.1                    
Component:  Raster       |     Version:  7.0.0                    
 Keywords:               |    Platform:  MacOSX                   
      Cpu:  Unspecified  |  
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 I have been looking for a way to create a raster direction map using a DEM
 in GRASS (I am currently using the stable 7.0.0 version). So far, the 3
 different scripts that do so (r.param.scale, r.shaded.aspect, and
 r.fill.dir) assume that 0 is at the East and count counterclockwise from
 there. The only way I can create a clockwise direction map with 0 at the
 North is to use the format "agnps" in r.fill.dir. However, this creates a
 map with directions ranging from 0 (equivalent to 0) to 8 (equivalent to
 360 degrees), which can be easily transformed into a 0-360 scale, but
 lacks precision.

 Would it be possible to add a flag in one of those scripts to create maps
 in degrees that have 0 to the North, 90 to the East and so forth? It would
 make it easier to integrate GRASS rasters to agent-based models.

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Ticket URL: <http://trac.osgeo.org/grass/ticket/2637>
GRASS GIS <http://grass.osgeo.org>