[GRASS-user] No Data everywhere when I extract the shadow from a DEM using r.sunmask

[Hakim Benoudjit]

Hello,

First of all, I'm new to this mailinglist and to GrassGIS in general.

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).
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).

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):

r.sunmask elevation=n46_e006_1arc_v3 at PERMANENT output=alps-sunmask.tif
year=2014 month=9 day=23 hour=9 minute=0 timezone=1


The problem I have is that the image produced is emtpy (no-data everywhere).
Is there a parameter I'm forgetting to add to the `r.sunmask` command?
Or should I use `r.sun` command instead, even though I'm not sure about the
parameters I should provide to it either ?

Hakim.
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