[Qgis-user] An issue with DEM terrain models

[Carlos Cerdán]

Hi Giacomo

Perhaps the SRC of your DEM is ESPG4326 (lat-long) if so, vertical units
are meters and horizontal units are degrees, then the relation between
vertical and horizontal units is 111111, and you must put that value in the
"scale" option. It is because 90° = 10'000,000 m (one cuarter of meridian).

Saludos

Carlos



2017-03-09 11:13 GMT-05:00 Giacomo Fontanelli <giacomofontanelli76 at gmail.com
>:

> Hi everybody
>
> I'm using a SRTM 4 (Geotiff, Int16 - Sixteen bit signed integer) and QGIS
> 2.18.1.
>
> I tried to produce a slope map using Raster > analysis > DEM (terrain
> model).
>
> In case I would like to have degrees as output i obtain a map with values
> from 89.5 to 90 degrees only, so almost impossible to classify.
>
> In case I flag the option"Slope expressed as percent" I obtain a map with
> more pixel values, but the slope is expressd with numbers from 0 to1971690.
>
> What's the problem?
>
> Thank you
>
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