[Tagging] Are tunnels only below ground? (Was Highway propertyproposal "covered-yes")

Martin Koppenhoefer dieterdreist at gmail.com
Tue Nov 3 00:48:54 GMT 2009

2009/11/3 Randy <rwtnospam-newsgp at yahoo.com>

> I might also tag a short section of the highway as "covered" in your first
> example, http://de.wikipedia.org/wiki/Br%C3%BCckenrasthaus_Frankenwald.
> Granted, that would be tagging for the renderers, because I am aware they
> have a real technical problem with properly rendering layers.

well, they would have less problems if they accepted layers, but their
rulemakers decided to ignore layers and render streets always above
buildings, that's where the problem arises (OK, otherwise the street would
be covered, also not the best solution). The best solution would be if the
rendering engine would itself detect hidden lines and render them as
interrupted lines or the like, but that's for the wishlist ;-)

> And, that if
> I was a purist, I would not do that. However, it is not an untrue tag, and
> I'm an engineer, not a scientist.

I'm also an engineer (well, kind of). In Germany tunnels are defined in some
standard (DIN 1076), but I'm aware that these standards are not valid all
over the world. English wikipedia gives some tunnel definitions:
"A *tunnel* is an underground passageway. The definition of what constitutes
a tunnel is not universally agreed upon. However, in general tunnels are at
least twice as long as they are wide."

till here I think it can be agreed on:
1. underground passage
2. at least twice as long a wide

the rest is more open to variations (e.g. in Germany the min. length for an
underpass that was excavated openly and then closed would be 80 metres to be
called a tunnel), and probably should be dealt with less strict:

"In addition, they should be completely enclosed on all sides, save for the
openings at each end. Some civic planners define a tunnel as 0.1
km <http://en.wikipedia.org/wiki/Kilometre>) in length or longer, while
anything shorter than this should be called an *underpass* or a
For example, the underpass beneath Yahata
Kitakyushu <http://en.wikipedia.org/wiki/Kitakyushu>,
Japan<http://en.wikipedia.org/wiki/Japan>is only 0.08 miles (0.13 km)
long and therefore should not be considered a

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