[Tagging] waterway=wadi problem

[Richard Z.]

On Sat, Jan 17, 2015 at 12:14:53PM -0800, Tod Fitch wrote:

> > 
> > usually you will assume it if there are ponds of open water or swamps 
> > in several places along a valley.
> 
> A pond/swamp/oasis/cienega in an arid or even semi-arid area is a significant feature that deserve mapping in its own right. Using that to infer information about a nearby or connected item seems a stretch to me.

ponds and such should be mapped. Infering an underground waterflow from them
may or may not be a stretch depending on the information that you have available. 
Often the underground waterflow is locally well known or can be inferred from
many other informations.

> The more I think about this issue the more I am coming to the feeling that waterway=wadi ought to be deprecated and we should come up with a way of further defining "intermittent" to distinguish between seasonal and ephemeral flow patterns. Based on other responses on this thread maybe:

that would be the best thing to do.. seems like otherwise every single mapper
would use wadi in a different way.

> waterway=*
> intermittent=yes/no (default assumption of "no")
> intermittent:frequency=winter/spring/summer/fall/seasonal/ephemeral/unknown (default assumption of "unknown")

  +intermittent:frequency=random_rare/random_frequent ?

We are still missing a definition of natural=valley afaics. There are
some old proposals but I have been told on some other mailing list that
valeys are nowadays mapped as a line natural=valley along the valley 
bottom.
So maybe we should also document this or make a proposal to that effect.

Richard