[Qgis-user] Manipulating DEM

2018-11-08 Thread Ulrich Kriechbaum 
Dear all!

 

I investigate a Glacial-Lake Outburst Flood and try to back-calculate the event using the simulation tool r.avaflow. During the event there was a big trench eroded. I have a post-event DEM with a clearly visible eroded trench. What i want to do now is to "flatten" out the trench so that i get a pre-event DEM to start my simulation. What i tried to do is to create the contour lines of the post-event DEM, change them so that they would not show the trench and then create a pre-event DEM out of this contour lines. I already asked the question, if anyone knows how to do that, i already got some nice answers but unfortunately none of the inputs really work for me

 

So now to my actual question: Does anyone know another method how to "flatten" out the trench in the DEM? I would be really glad if someone would have an answer, as i have ben struggling a while now with these problem..

 

Best regards,

 

Ulli
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[Qgis-user] Creating DEM from Contour lines

2018-11-08 Thread Ulrich Kriechbaum 
Hello all!

 

I investigate a Glacial Lake Outburst Flood which eroded a lot of material. What i try to do is to backcalculate the event with the simulation tool r.avaflow. For my simulations i need a Pre-Event DEM. I have a Post-Event DEM where the eroded trench is clearly visible. So what i did was to project the Contour lines of the Post-DEM, change them so that the trench is "flattened". Now i try to generate a Pre-Event DEM with these Contour lines. That's the point at which i am struugling. I tried to interpolate the Contour lines (TIN and IDW) but the results were not really satisfying.

 

Does anyone have an idea how to get a nice DEM from contour lines?

 

Best regards,

 

Ulli
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