Hi Ulli:
If I understand your project correctly, you only have the post DEM and
you want to remove the new trench so that you can perform some
additional analysis. SO, off the top of my head, I would digitize a
polygon whoch defines the extent of the trench. I would use this
polygon to erase the points derived from the contour lines and then
create your DEM from the resulting pointg layer without elevations
inside the trench. You can try different techniques for creating the
dem using the saga griding functions within the processing toolbox. By
using a TIN approach, the result may be a bit blocky. If yopu try a
B-spline interpretation, the results will be smoother, however
individual elevations are interpreted along a spline and therefore may
over or underestimate the actual elevations.
Hope this helps
Kirk
On 11/8/2018 9:49 AM, Ulrich Kriechbaum wrote:
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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Kirk Schmidt, MScF, BScF, RPF
General Manager
Nortek Resource Solutions Inc.
RR # 1
Thorburn, NS
B0K 1W0
Tel (902) 922.3607
Email: [email protected]
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