Strahler stream order

The stream order according to Strahler specifies the degree of branching of a hydrographic network. It forms the basis for morphological studies and descriptions of a watercourse. --- According to Strahler, watercourse sources are assigned a stream order of 1. If two tributaries of the same stream order join, the order increases by 1. The Rhine and the River Aare have a stream order of 9, whereas the Rhône has a stream order of 7. --- The stream order was calculated using the VECTOR25 hydrographic network.