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<div class="moz-cite-prefix">On 09/04/2017 05:15 PM, Hakim Benoudjit
wrote:<br>
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cite="mid:CAC0V5F-eAszJ4Cyhw7kTqEZF=1vrAjKNy3a4XXDE7OiZcz9LLg@mail.gmail.com">
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<div>Hello,<br>
<br>
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First of all, I'm new to this mailinglist and to GrassGIS in
general.</div>
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Welcome<br>
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cite="mid:CAC0V5F-eAszJ4Cyhw7kTqEZF=1vrAjKNy3a4XXDE7OiZcz9LLg@mail.gmail.com">
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<div>So, I'm trying to use the `r.sunmask` command in order to
extract the shadow from an `SRTM DEM` of the Alps mountains
(Switzerland).</div>
<div>The image had to be first `reprojected` when I've
imported it to a `EPSG:21781` location, in order to get both
the (lat, lon) in meters (similarly to the elevation). <br>
</div>
<br>
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<div>Here is the command I'm executing (note that the time of
the day was chosen at 09:00 in the morning to maximize the
shadow):</div>
<div><br>
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<pre><code>r.sunmask elevation=n46_e006_1arc_v3@PERMANENT output=alps-sunmask.tif year=2014 month=9 day=23 hour=9 minute=0 timezone=1</code></pre>
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<div><br>
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<div>The problem I have is that the image produced is emtpy
(no-data everywhere).</div>
<div>Is there a parameter I'm forgetting to add to the
`r.sunmask` command?</div>
<div>Or should I use `r.sun` command instead, even though I'm
not sure about the parameters I should provide to it either ?<br>
</div>
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Most likely you need to set the region to your DEM.<br>
<font size="+1"><tt>g.region -p </tt></font><tt><font size="+1"><code>rast=n46_e006_1arc_v3@PERMANENT<br>
<br>
</code></font></tt>FAQ #1 when using GRASS: Always set the
region first<tt><font size="+1"><code><br>
</code></font></tt>
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cite="mid:CAC0V5F-eAszJ4Cyhw7kTqEZF=1vrAjKNy3a4XXDE7OiZcz9LLg@mail.gmail.com">
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Hakim.<br>
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<br>
<pre class="moz-signature" cols="72">--
Micha Silver
Ben Gurion Univ.
Sde Boker, Remote Sensing Lab
cell: +972-523-665918</pre>
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