[OSM-talk] Bridges / viaducts for railways

[Steven te Brinke]

Hello,

As a sailor I like to know if a bridge is a moveable one, and I think 
this is also interesting for cars, because they might need to wait. So I 
agree that bridge=true is not enough, I would like to be able to have a 
bridge=moveable. It is also possible to add the type of bridge (lift, 
swing, bascule, ... - wikipedia has some beautiful animations of them: 
http://en.wikipedia.org/wiki/Moveable_bridge).
So I think a viaduct=yes or a viaduct=<type> would be a good idea. At 
least the current way viaduct is used doesn't seem to be a good one. And 
I think a viaduct and a bridge are quite different things, so it's no 
problem to give them their own tag.

Steven


Dave Stubbs schreef:
>
> That's usually the plan I think. The main problem we have with putting 
> this into practice, is that to maintain an optimal number of tags we 
> need to know the entire tagging domain before we start... which we 
> don't.  So taking your example, if instead of bridge=yes we allow 
> bridge=suspension, we don't actually have a problem (assuming 
> everybody agrees to assume the existence of the bridge tag implies a 
> bridge regardless of the value, maybe excluding "no"). But if we had 
> started with transit=bridge/tunnel/ferry, then we'd still need the 
> bridge tag anyway because it's probably not sensible to add the 
> transit=suspension_bridge etc, simply for the ease of processing. 
> Ofcourse you could argue we need the transit tag, and just don't have it.
>
> I think for many of these things where we have x=yes/no, we find that 
> there is often a number of subtypes that could be substituted for the 
> "yes". Although most people probably wouldn't know how to classify 
> them, and just want to record the main type.
>  
> Dave