[Tagging] Tunnels and bridges

Martin Koppenhoefer dieterdreist at gmail.com
Fri Feb 1 15:13:56 GMT 2013

2013/2/1 fly <lowflight66 at googlemail.com>:
> 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),

This is a misconception, there are actually no international (unified)
standards for this, it depends on the country (or locally valid
standards) and the 80 meter limit (in Germany) is not a general
minimum limit for tunnels but is an exception for tunnels not drilled
into the ground but created by excavating from above and covering
succesively (the latter are also considered tunnels by the German DIN
1076 if longer than 80 meters).

> 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 wouldn't add the ways below into a bridge relation, astonished that
this is proposed. The relevant information for boat traffic below the
bridge is the clearance (that depends other than on the bridge also on
the water level) and should be tagged on the way it applies to (the
part of the waterway below the bridge). The relation between the
crossing way below and above is given by the geometry (and layer

> I know bridges with one name but several parallel independent structures.

yes, clearly the common name shouldn't be the only criterium


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