[GRASS-dev] Re: [GRASS GIS] #498: r.sun2 out of sync / broken svn history

[GRASS GIS]

#498: r.sun2 out of sync / broken svn history
---------------------+------------------------------------------------------
  Reporter:  hamish  |       Owner:  hamish          
      Type:  defect  |      Status:  assigned        
  Priority:  major   |   Milestone:  6.4.0           
 Component:  Raster  |     Version:  svn-develbranch6
Resolution:          |    Keywords:  r.sun           
  Platform:  Linux   |         Cpu:  x86-32          
---------------------+------------------------------------------------------
Comment (by hamish):

 > Q1) how small must the horizonstep be to recreate the beam_rad
 > output map effectively as good as e.g. seen in the r.sun wiki
 > page example?

 trials showing differences between no horizon steps; trying to find the
 ideal "sweet spot" compromise between time and quality.

 note that none are perfect. Standard r.sun with no horizon inputs is
 slightly clipped in lower east wing; the 360x 1 degree horizon map has
 slightly uneven width between inner east & west bands.
 note2 color tables are not constant between maps.

 see attached screenshot (rsun_horizons.png)

 test script:
 {{{
 for DEG in 1 15 30 ; do
    # can take a while to create all maps
    r.horizon elev=gauss horizonstep=$DEG dist=0.7 horizon=horangle$DEG

    time r.sun -s elevin=gauss day=$DAY horizon=horangle$DEG \
      horizonstep=$DEG beam_rad=rad_test.355.beam.Hz${DEG}deg.try5
 done


 # r.sun with no horizon seeds
 real    3m7.571s
 user    3m7.444s
 sys     0m0.060s

 # r.sun with 360x 1 deg seeds
 #  sits quite a while at 0% due to loading sheer number of horizon maps!
 real    1m20.385s
 user    1m18.853s
 sys     0m1.272s

 # r.sun with 24x 15 deg seeds
 real    0m32.185s
 user    0m31.774s
 sys     0m0.248s

 # r.sun with 12x 30 deg seeds
 real    0m29.518s
 user    0m29.382s
 sys     0m0.120s
 #
 }}}

 {{{
 plot_stuff()
 {
 r.colors $MAP -e color=bcyr
 d.rast "$MAP"
 d.vect gauss_200m_contours color=180:180:180
 echo "$1" | d.text color=black
 eval `r.univar -g $MAP`
 echo "sum: $sum" | d.text color=black at=1,5
 d.legend "$MAP" range=1300,1500
 }

 ###
 d.mon x2
 d.resize w=1024 h=768
 d.split.frame 4
 #
 d.frame uno
 MAP=rad_test.355.beam.try5
 plot_stuff "Std."
 #
 d.frame dos
 MAP=rad_test.355.beam.Hz1deg.try5
 plot_stuff "w/ 1 degree horizon seeds"
 #
 d.frame tres
 MAP=rad_test.355.beam.Hz15deg.try5
 plot_stuff "w/ 15 degree horizon seeds"
 #
 d.frame cuatro
 MAP=rad_test.355.beam.Hz30deg.try5
 plot_stuff "w/ 30 degree horizon seeds"
 ###
 d.frame full_screen
 #d.out.file out=rsun_horizons format=png
 }}}

 next I will try std and 1deg horizons with a r.sun time step of 3 min
 instead of 30 minutes. (sun travels ~1deg of sky in 4min)


 Hamish

-- 
Ticket URL: <https://trac.osgeo.org/grass/ticket/498#comment:9>
GRASS GIS <http://grass.osgeo.org>