[Tagging] Tunnels and bridges

[Peter Wendorff]

Am 31.01.2013 16:57, schrieb Janko Mihelić:
>
> Well, having building=bridge and bridge=yes isn't two features. First 
> one is "the" feature (bridge) and the second one is the road with an 
> attribute (it is on a bridge). They are redundant, but I wouldn't call 
> them duplicated.
They are duplicated if you follow the old scheme, where bridge=yes in 
fact was "this is a bridge - or part of a bridge".
But on the other hand if you follow the old scheme (and we don't use 
building=bridge for the area, as stated dangerous above because of the 
nearly-free-text-character of building=*) you would completely ignore 
the bridge area, and thus you don't get a duplicate again.

For the future that would mean:
"man_made=bridge (or whatever) means, that this area is a bridge 
(analogon: building)"
"bridge=yes means, if you are going/driving on that way, you go/drive 
over a bridge"
Please note: The second sentence was true in the past, too.

For data consumers not dealing with the new scheme it follows: nothing 
changed (except probably naming, which was a problem already with the 
name-conflict between highways and bridges name).
For data consumers supporting the new it follows: If there's no 
bridge-area (e.g. man_made=bridge) defined, but there's a bridge=yes, I 
have to assume an error, I might report that as such and/or I should 
fall back to assume a bridge-area at/around the way, which is simple by 
creating a rectangle with the assumed bridge width around the way.

regards
Peter