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
--
Adjunct Professor University "Roma Tre"
Gis Applied for Environmental studies
Risk modelling & Hydrogeology
Consultant DFID-UK, United Nations, EU projects
AZZURRA LENTINI
++++++++++++++++++++++++++
Italy Mobile Tel.: **(39) 338 24 40 676
++++++++++++++++++++++++++
SKYPE azzurrahydro
++++++++++++++++++++++++++
*[email protected] <mailto:[email protected]>_*
*[email protected] <mailto:[email protected]> _**__*
++++++++++++++++++++++++++
*Par respect pour l'environnement,*
*n'imprimez ce mail qu'en cas d'absolue nécessité*
_______________________________________________
Qgis-user mailing list
[email protected]
List info: https://lists.osgeo.org/mailman/listinfo/qgis-user
Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user
--
Mit freundlichen Grüßen
Stefan Giese
Projektleiter/Consultant
----------------------------------------------------
Aufwind durch Wissen!
Web-Seminare und Online-Schulungen
bei der www.foss-academy.com
----------------------------------------------------
WhereGroup GmbH
Schwimmbadstr. 2
79100 Freiburg
Germany
Fon: +49 (0)761 / 519 102 - 61
Fax: +49 (0)761 / 519 102 - 11
[email protected]
www.wheregroup.com
Geschäftsführer:
Olaf Knopp, Peter Stamm
Amtsgericht Bonn, HRB 9885
_______________________________________________
Qgis-user mailing list
[email protected]
List info: https://lists.osgeo.org/mailman/listinfo/qgis-user
Unsubscribe: https://lists.osgeo.org/mailman/listinfo/qgis-user
