Derive all subcatchments from a DEM using PCRaster in QGIS
Channel: Hans van der Kwast
Date: 2021-05-24

This video shows how to use the PCRaster QGIS tools to derive all subcatchments from a DEM.
We'll convert a DEM in GeoTIFF format to PCRaster format. Then we'll derive the local drain direction map. Next, the streamorder tool is used to derive the Strahler orders. After calibration we determine the orders of the channels from which we derive the outlets of the subcatchments.

**NOTE THAT THE WORKFLOW CAN NOW BE DONE WITH THE PCRASTER TOOLS PLUGIN, WHICH HAS SOME BUGS FIXED**

0:00 Introduction and workflow
1:53 Convert to PCRaster format
2:20 Create local drain direction map (lddcreate)
3:20 Calculate Strahler orders (streamorder)
4:07 Derive channels from Strahler orders
5:32 Create lookup table with RAT
6:37 Reclassify Strahler orders (lookup)
7:24 Find downstream Strahler order (downstream)
7:52 Use raster calculator to find junctions
9:07 Give outlets unique ID (uniqueid)
9:56 Convert layer data type
10:30 Create nominal zero map (spatial)
10:49 Fill nodata (cover)
11:24 Derive subcatchments (catchment)
12:00 Derive subcatchments (subcatchment)
12:44 Give subcatchments their Strahler order (areamaximum)

Link to repository: https://github.com/jvdkwast/qgisrepository

Linkt to PCRaster: http://www.pcraster.eu

#PCRaster #QGIS