A common analysis from a DEM is to compute hydrological elements, such as the channel network or the set of watersheds. This recipe shows you the steps to do these analysis.
In the Processing Toolbox option, find the Fill Sinks algorithm and double-click on it to open it:
Select the DEM in the DEM field and run the algorithm. This will generate a new filtered DEM layer. From now on, we will just use this DEM in the recipe and not the original one.
Open Catchment Area and select the filtered DEM in the Elevation field:
Run the algorithm. This will generate a catchment area layer:
Open the Channel network algorithm and fill it in, as shown in the following screenshot:
Run the algorithm. This will extract the channel network from the DEM, based on the catchment area, and it will then generate it as both a raster and vector layer:
