Thanks guys for the quick response. You were right, the shadow wasn't detected because the region hasn't been set.
Now it seems to be working, but I'm wondering between `r.sunmask` and `r.sun` which one should be used to calculate the shadow mask? Thanks. Hakim. On 4 September 2017 at 15:43, Micha Silver <[email protected]> wrote: > > > On 09/04/2017 05:15 PM, Hakim Benoudjit wrote: > > Hello, > > First of all, I'm new to this mailinglist and to GrassGIS in general. > > Welcome > > > 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@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 ? > > Most likely you need to set the region to your DEM. > g.region -p rast=n46_e006_1arc_v3@PERMANENT > > FAQ #1 when using GRASS: Always set the region first > > > Hakim. > > > _______________________________________________ > grass-user mailing > [email protected]https://lists.osgeo.org/mailman/listinfo/grass-user > > > -- > Micha Silver > Ben Gurion Univ. > Sde Boker, Remote Sensing Lab > cell: +972-523-665918 > >
_______________________________________________ grass-user mailing list [email protected] https://lists.osgeo.org/mailman/listinfo/grass-user
