[Qgis-user] convex and concave areas

[Stefan Giese (WhereGroup)]

one process could be:

  * smooth the DTM by a neigbourhood analysis. The width depends on the
    size of your convex and concave areas. you can use a mean filter or
    lowpass for example
  * substract the filtered from the original
  * select values > or < your cutoff
  * convert this into polygons

see 
https://www.researchgate.net/profile/Hazen-Russell/publication/277324326_A_semi-automated_esker_detection_method_EDM_for_improved_quantification_of_glaciated_landscapes/links/5567b6ca08aeab77721eac23/A-semi-automated-esker-detection-method-EDM-for-improved-quantification-of-glaciated-landscapes.pdf 
for further reading

Hope this helps

Stefan

Am 05.05.2021 um 10:02 schrieb Azzurra Lentini:
> Hi list,
> I need to find the convex and concave areas from a dtm raster file. Do 
> you have any suggestions?
> Thanks
>
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