[Tagging] Tunnels and bridges

fly lowflight66 at googlemail.com
Fri Feb 1 15:02:55 GMT 2013

Thanks for the conclusion, Martin.

I have no problem to change my building=bridge into man_made but we have to
straighten our definition of building=*. Same is also true for bridge and tunnel
as for a tunnel you need a certain length to call it tunnel (think it is 80m),
everything else is a bridge. In Germany more and more bridges are built for
animal crossing often without any highway.

Think we are missing some points though:

In my opinion the major problem is that without the relations
(type=bridge/tunnel) we do not have any connection between a way crossing under
a bridge/above a tunnel. Especially for waterways this might be really useful
information not only for boot traffic but also in case of high water and flood.

I know bridges with on name but several parallel independent structures.

The type=tunnel is not wide spread probably due to missing information and no
working routing without GPS, but we really need it.
* For sure to add the proper name and ref as it has nothing to do with the
highway/railway/powerline leading through the tunnel
* to group the different tubes as for example on Swiss motorways they often
belong together and there are also connections between them and escape tubes.
* to add all the escape ways, kilometre signs and maybe the air conditioning system.

My conclusion is:
1. We can introduce man_made=bridge in favour of building=bridge.
2. We either need a relation for almost every bridge/tunnel or a new subtagging
system on the highway/railway etc like bridge:name, bridge:ref ...
3. Rendering might be one problem but the data should also be useful for other
task like: Tell me all bridges crossing a waterway/highway within a certain
distance or along a route.
4. Not only a problem of this thread but we need to get much more developers to
support relations (eg. renderes, editors, search engines and other consumers).
This includes evaluating existing relations and adjusting them to be useful.


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