[Tagging] Mapping cave tunnels passable by human

[Friedrich Volkmann]

On 14.08.2014 07:29, Mateusz Konieczny wrote:
> I added to http://wiki.openstreetmap.org/wiki/Cave#Tagging_in_OSM how
> these may be mapped

Given that you want to discuss wiki changes, you should start the discussion
before you actually do the changes. You should also refer to this mailing
list thread in the comment of your wiki change, or in the talk page. I
received an automated notification that you changed the wiki and did not
know about the mailing list thread, so I corrected the wiki. Now I am
surprised that there's a discussion in another medium.

> ("tunnels that are available for humans but closed for typical
> tourists may be mapped as highway=path with tunnel=yes and access=private,
> and routes available for tourists as highway=footway (highway=steps) with
> tunnel=yes").

I am not sure about English terminology. In German, we call natural cavities
"Höhlen" (caves), and artificial cavities "Stollen" (adits?). A straight
"Stollen" with an entrance on each end is a "Tunnel" (tunnel). I think that
the meaning of the English word "tunnel" is just the same as in German. In
that case, tunnels and caves are mutually exclusive.

I also do not understand why you connect highway=path with private access.
Paths may or may not be publicly accessible, as are footways. Footways are
by definition even more restricted, namely to pedestrians.

> I think that it is an obvious idea, but wiki claimed that "At the moment
> there just a
> tag to map the entrance to a cave." despite fact that existing tags fit well.

No, they do not fit. Caves are complex three-dimenional structures. In most
caves there are no paths. You go or climb or rope down whereever you feel like.

> I am pretty sure that it is a good idea, but maybe there is some superior
> scheme or
> I missed something.

There is no scheme, and I doubt that cave maps belong in a geo database.
Cave maps are very detailed, and there are special applications for cave
rendering. For Austria, there's also a database called Spelix, accessable
via web browser. It contains cave surveys and maps, photos and other data.
Getting all of that data to OSM would mean continuous duplicated effort and
yet the data in OSM will never be as complete as the original data. I have
surveyed a lot of caves and for sure I will not draw all of my cave maps
again only to get them into OSM. If you are interested in caves, get access
to dedicated cave databases.

> I wonder about adding something that would denote that way is part of cave,
> maybe natural=cave_tunnel?

See above. A tunnel is not a cave. If you want to express that a way is
underground, use layer=-1.

-- 
Friedrich K. Volkmann       http://www.volki.at/
Adr.: Davidgasse 76-80/14/10, 1100 Wien, Austria