[GRASS-dev] r.sun artifacts

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1

Hi, this is my first post and I hope someone could help me.
I'm using r.sun for computing a solarmap of the alpine arch in Friuli
Venezia Giulia (IT).
I'm using this command:

r.sun -s elevin=dem_40_fvg_wgs84 aspin=asp_fvg_wgs84 slopein=slo_fvg_wgs84
lin=1.5 alb=0.2 horizonstep=10 beam_rad=irr_fvg1 insol_time=ins_fvg1
diff_rad=diffuse_irr__fvg1 refl_rad=ground_refl_fvg1
glob_rad=total_irr_fvg1 day=1 step=0.25 dist=1.0 numpartitions=1
--overwrite

But the resultant map have a lot of artifacts (lines of pixels with wrong
values, see the attachment)
http://osgeo-org.1803224.n2.nabble.com/file/n6917645/r.sun.jpg

I've tried to delete "aspin" and "slopein" parameters and i've changed
"step" and "dist" with no results.
What can i do for remove this artifacts? Except for this problem the map is
good.

I'm using Grass6.4.1. My OS is W7 64bit.

thx

Sergio

p.s. sorry for my english

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2

On Fri, Oct 21, 2011 at 7:08 PM, Sergio Gollino <gollinosergio@gmail.com> wrote:

Hi, this is my first post and I hope someone could help me.

Welcome here!

I'm using r.sun for computing a solarmap of the alpine arch in Friuli
Venezia Giulia (IT).
I'm using this command:

r.sun -s elevin=dem_40_fvg_wgs84 aspin=asp_fvg_wgs84 slopein=slo_fvg_wgs84

try to avoid aspin= and slopein= since r.sun can also calculate
those internally.

lin=1.5 alb=0.2 horizonstep=10 beam_rad=irr_fvg1 insol_time=ins_fvg1
diff_rad=diffuse_irr__fvg1 refl_rad=ground_refl_fvg1
glob_rad=total_irr_fvg1 day=1 step=0.25 dist=1.0 numpartitions=1
--overwrite

... this part looks ok.

But the resultant map have a lot of artifacts (lines of pixels with wrong
values, see the attachment)
http://osgeo-org.1803224.n2.nabble.com/file/n6917645/r.sun.jpg

I've tried to delete "aspin" and "slopein" parameters and i've changed
"step" and "dist" with no results.

Mhh. So please check the DEM then bu calculating a shaded map with
r.shaded.relief. Perhaps the artifacts are therein?

I'm using Grass6.4.1. My OS is W7 64bit.

I had no such problems in a close-by area with the same version (but Linux
which should not matter here).

Markus

3

Thx for your reply. As you sad, the problem was in the DEM (but I don't know
why).
I created a new mapset (equal than the old) and I reprojected the DEM (with
r.proj) again. So, now, there aren't any artifacts. The map it's all good.

Thank you!

Sergio Gollino

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