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OGGM / oggm

Open Global Glacier Model
http://oggm.org
BSD 3-Clause "New" or "Revised" License
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No distinction between glacier and its surroundings when creating topo_smoothed #1437

Open anoukvlug opened 2 years ago

anoukvlug commented 2 years ago

The procedure that smooths the DEM, smooths both the glacier and its surrounding at the same time, without making a distinction between the two. As a result you get odd elevation contours in some cases, where the glacier tongue is located between steep walls. I don't have the overview of where this might have an impact, but it might be worth to reconsider/ to take into account when reconsidering the smoothing (#673).

See the Hintereisferner tongue as example. tongue_smoothed_hintereisferner

The reason that I ran into this issue, is that when redistributing the glacier covered area onto a map, having smoothed topo is useful. However having a glacier surface that is curved into the wrong direction leads to other issues.

fmaussion commented 2 years ago

when redistributing the glacier covered area onto a map, having smoothed topo is useful

Why?

it might be worth to reconsider/ to take into account when reconsidering the smoothing

You can also do any kind of smoothing you want in the distribute task? Since its all about "cosmetics" anyway...

anoukvlug commented 2 years ago

Why? I use the topo_smoothed to link all grid points based on their height to a specific point along the flowline. I use these sections (combined with other details) later on to assign which grid points become ice free first as the glacier evolves.

You can also do any kind of smoothing you want in the distribute task? Since its all about "cosmetics" anyway... Yes, that is true. I was just thinking if I should work around the issue or solve it ;)