sent from a phone

> On 17. Aug 2018, at 13:43, Christoph Hormann <o...@imagico.de> wrote:
> 
> If you want to map the river width tag width=*, if you don't want to map 
> the width then don't create classes based on width thresholds.


river size is not about width alone, the most generic approach to measure size 
is looking at the quantity of water per time. It accounts for width, depth, 
flow speed in one parameter. For the significance, length is probably also 
interesting.
The width alone depends on factors like the terrain and its geology. 

These numbers are most useful in relation to other waterways nearby. The 
context matters, the same amount of water in one area might be a stream and in 
another a river.

Usually at the confluence the name of the waterway with the most water is the 
one whose name prevails, but sometimes there are exceptions, e.g. for historic 
reasons (e.g. they didn’t know exactly which river brought more water, or 
considered one more important for other reasons)

For navigation it is interesting to know if you can cross the waterway without 
bridge, tunnel or ford by jumping over it (width) or by walking through it 
(depth).


Cheers,
Martin


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