[GRASS-user] extract slope lower than 25 meters ?

[Moritz Lennert]

On 03/04/15 09:45, image93 wrote:
> Good morning, I have to extract slope lower than 25 meters. But i'm
> working with SRTM raster DEM 30 meters resolution... 1/ Is there a tool
> with qgis in order to extract slope values? 2/ According to you, is it
> possible to extract 25 meters slope values with srtm 30 meters. if it is
> not the case, do you know another way? Another DEM more acurate for
> instance? Thank you very much.

You can always interpolate from 30m resolution data to an estimation of 
higher-resolution data, for example using v.surf.rst. However, this will 
always only be an estimation, not the real altitude data. If you want 
real slope you have to find a higher-resolution DEM. Which region are 
you working on ?

For France, IGN-France has higher-resolution products.

Moritz