[Qgis-user] Calculate upslope catchment areas for multiple points?

[Ben Jones]

Hello All,

I have used SAGA to generate channel networks and r.watershed to generate catchment sub-basins from Copernicus 30 m DEM data to assist with planning a stream sediment sampling program. Once samples are collected I would like to generate polygons that define the upslope area for each sample point.

I understand that this can be done using SAGA Terrain Analysis ‘Upslope area’ tool that requires manually copying and pasting the X and Y coordinates for each sample point (one point at a time which works but is not practical for 100’s of samples, or in batches which is still not ideal and doesn’t appear to work?).

Is there an easy way to import a point file with multiple points (100’s of points) to SAGA or another tool to automatically calculate upslope catchment areas for each of the points?

I have come across two potential solutions:

1) ‘Qgis SAGA Upslope Area for several points automation’:
https://gis.stackexchange.com/questions/342333/qgis-saga-upslope-area-for-several-points-automation
2) ‘Snap pour points and delineate multiple catchments in QGIS’:
https://www.youtube.com/watch?v=Hqc_1CMadhA

However, both are three years old and it appears there are complications using both these methods in newer versions of QGIS3. Are there alternative methods?

I am using QGIS 3.28.11a on macOS Monterey.

Thanks,

Ben