[GRASS-dev] [GRASS GIS] #2014: r.sun using EPSG:3031 projection gives strange results

GRASS GIS trac at osgeo.org
Fri Jun 21 21:09:49 PDT 2013

#2014: r.sun using EPSG:3031 projection gives strange results
 Reporter:  pierreroudier  |       Owner:  grass-dev@…              
     Type:  defect         |      Status:  new                      
 Priority:  normal         |   Milestone:  7.0.0                    
Component:  Raster         |     Version:  svn-trunk                
 Keywords:  r.sun          |    Platform:  Linux                    
      Cpu:  x86-64         |  
Changes (by hamish):

  * keywords:  => r.sun



 I saw the post on the mailing list and will have a look at it -- it might
 take me a little while to get to it though. You might try to compare with
 the version of r.sun in GRASS 6.4.3svn, as in GRASS 7 some map projection
 calculations have been moved out of the main loop to allow the
 GPU/multiprocessor acceleration to work.

 It won't necessarily fix it, but it may be useful to test.

 A couple other things to look at: is the sun over or under the horizon
 when it happens (there may be no direct sun but still some diffuse
 radiation?), and if PROJ.4 is handling the projection properly
 (projections not "north up" (which way is north in a polar
 stereographic?), non-Greenwich prime meridians etc.)

 in general, polar stereographic is known to work, at least with v.proj:


Ticket URL: <https://trac.osgeo.org/grass/ticket/2014#comment:1>
GRASS GIS <http://grass.osgeo.org>

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