[OSM-talk] [tagging] Bridge proposal

[Lester Caine]

Raphael Studer wrote:
>>> Maybe you should wait some days. There is some activity on the talk
>>> page cause of the Bridge_and_Tunnels Relations proposal:
>>> http://wiki.openstreetmap.org/index.php/Relations/Proposed/Bridges_and_Tunnels
>> A proper definition of what a relation is may be a good start ;(
> 
>> I don't see why a single mapped element should be defined as a 'relation'. A
>> relation would be used to join a number of mapped elements making up a bridge,
>> as where several ways make up the one 'bridge' such as some complex motorway
>> junctions. Adding AREAS to the equation simply reopens the debate whether
>> EVERY way should properly define it's area. i.e. roads carriageways making up
>> the bridge should have widths as well.
>> And then add multi-deck bridges and roadways which are single ways on top of
>> one another ;)
> 
> This multi-deck bridges would be a good example, why having relations
> for bridges.
> An other example are if you have a highway and a cycleway on the same
> bridge. Or a railway and a footway.

Relation should be IN ADDITION to identifying elements that make it up, not as 
a replacement which is what is being proposed.
Areas provide physical with details that are missing from routes, but also do 
not replace the basic elements such as 'railway and footway' that form part of 
the bridge.

-- 
Lester Caine - G8HFL
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