If you zoom in you see a length in km next to each river. For small ones it looks like it is the total length of that waterway. For bigger rivers that I'm familiar with I was not able to make sense of that number. It is not the length, it's too big for that. Maybe it's the total length of that waterway and all connected waterways? It also does not change when I travel along that waterway.
My example is the river Neckar close to Heidelberg in Germany. The number there is:2595963 km
In reality the length of each river is measured from it's estuary. For bigger waterways in Germany you see a sign every kilometer with a number. The number is the distance in kilometers to the estuary of that waterway.
My example is the river Neckar close to Heidelberg in Germany. The number there is:2595963 km
In reality the length of each river is measured from it's estuary. For bigger waterways in Germany you see a sign every kilometer with a number. The number is the distance in kilometers to the estuary of that waterway.