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<p>Hi Ulli:</p>
<p>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.</p>
<p>Hope this helps</p>
<p><br>
</p>
<p>Kirk<br>
</p>
<div class="moz-cite-prefix">On 11/8/2018 9:49 AM, Ulrich Kriechbaum
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:trinity-4b7e5630-0968-48bd-a04d-b7c241d44423-1541684952067@3c-app-gmx-bs54">
<div>
<div>Dear all!</div>
<div> </div>
<div>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....</div>
<div> </div>
<div>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..</div>
<div> </div>
<div>Best regards,</div>
<div> </div>
<div>Ulli</div>
</div>
<br>
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<pre class="moz-signature" cols="72">--
Kirk Schmidt, MScF, BScF, RPF
General Manager
Nortek Resource Solutions Inc.
RR # 1
Thorburn, NS
B0K 1W0
Tel (902) 922.3607
Email: <a class="moz-txt-link-abbreviated" href="mailto:kirk@nortekresources.com">kirk@nortekresources.com</a>
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