[Tagging] How to tag shared waterway highway

[Andy Townsend]

On 08/12/2018 10:31, Joseph Eisenberg wrote:
> I would recommend drawing a separate “way” for the highway. I imagine 
> that the route taken by vehicles or people walking is a few meters off 
> of the center of the waterway, and perhaps a little straighter. If you 
> are coarsest tracing the waterway and road, then the two ways might 
> share most of their nodes.


Drawing separate ways for highway and waterway but sharing the same 
nodes will also lead to problems - there's no way that data consumers 
will know that this highway is also a waterway.  If you're going to do 
that then you'll need to add some other tag to the highway to say "you 
may get wet".

Highways and waterways using exactly the same route is pretty common 
where I am in the UK - they're called "long fords" (we don't have many 
wadis), and a ford=yes tag allows renderers to process them.  I'd 
imagine for wadis some other tag (maybe some sort of "hazard"?) would be 
more appropriate, but it needs something.

Best Regards,

Andy