Opened 11 years ago

Last modified 8 years ago

#2081 new defect

r.sun (mode 2): sawtooth bug in diffuse irradiation map

Reported by: hamish Owned by: grass-dev@…
Priority: major Milestone: 6.4.6
Component: Raster Version: svn-develbranch6
Keywords: r.sun Cc:
CPU: x86-64 Platform: Linux

Description

Hi,

in investigating #2014 I noticed there's a bug in the calculation for diffuse sunlight when the sun is at low angles to the horizon. the overall trend seems ok, but there's a sawtooth pattern which follows the curvature of the lines of latitude.

The attached screenshots are for Ross Island in Antarctica, epsg:3286 bounds: 

north:      1437000
south:      1341000
west:       17000
east:       119000
res:        100

?

made with: 

DAY=060
r.sun -s elevin=etopo1.ross_island step=0.05 \
       beam_rad=erebus.direct.$DAY diff=erebus.diffuse.$DAY day=$DAY

thanks, Hamish

Attachments (3)

day060diffuse_annotated.png​ (183.6 KB ) - added by hamish 11 years ago.
nviz view
diffuse60_follows_lat.png​ (118.6 KB ) - added by hamish 11 years ago.
anomaly follows lines of constant lat
diffuse60_profile.png​ (22.0 KB ) - added by hamish 11 years ago.
north-south profile

Download all attachments as: .zip

Change History (4)

by hamish, 11 years ago

Attachment: day060diffuse_annotated.png​ added

nviz view

by hamish, 11 years ago

Attachment: diffuse60_follows_lat.png​ added

anomaly follows lines of constant lat

by hamish, 11 years ago

Attachment: diffuse60_profile.png​ added

north-south profile

comment:1 by neteler, 8 years ago

Milestone: 6.4.4 → 6.4.6
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