[Tagging] Thoughts on how to replace or modify an exist/established tag (Was: Feature Proposal - RFC - sluice_gate)

M∡rtin Koppenhoefer dieterdreist at gmail.com
Fri Jan 7 17:56:13 GMT 2011

2011/1/6 Simone Saviolo <simone.saviolo at gmail.com>:
> ...for example, in the last
> few weeks on talk-it we exhumed once again the problem that an amenity=bar
> is not really a "bar" as we conceive it in Italy. Sadly though, despite the
> interesting debate, and notwithstanding the fact that both parties are
> "quite right", this means that in fact bars aren't mapped reliably at least
> in Italy,

Yes, the problem was (is), that some mappers decided to map (italian)
bars as cafes, which they clearly aren't, so now it is even harder to
find a cafe. ;-)

This is just one example of many, that arise when mapping the whole
world. Different cultures are different. We try to describe them all
with tags in british English, but it is hard. We had a similar problem
in Germany some time ago, when we tried to differentiate between
"Schloss" (castle, palace, stately home, château in BE) and "Burg"
(castle in BE). The world is complex. Some words can't be simply
translated, not only does the translation depend on the context, there
is also different general properties of "similar" objects.

IMHO this means that who is looking at the map has to interpret it
according to _where_ he is (and therefor needs some "cultural"
background about the place). If I want to buy tobacco in Germany at
night, I would go to a petrol station. In Italy I would go to a bar.
But we can't (maybe, I'm not sure what the future brings) have
complete lists of all country specific goods and services that are
offered in certain features, or of all of their properties. And we can
not expect of the mappers to go that deep into detail for every
feature (actually there are some attempts to do this, e.g. dozens of
tags for accepted payments at petrol stations).

And currently most of the mapping and tags are still developped by
mappers with similar cultural background, but IMHO OSM should also be
the best map in the rest of the world.

We can try to solve this up to a certain limit though. We should try
to have short, precise definitions of the tags, starting with broad
basic and inclusive definitions on the top level and then refine the
details with subtags. If something doesn't fit into a given
definition, we should invent a new tag / subtag.

Currently our tagging system is very flat, sometimes going into deep
detail on the toplevel (landuse=brownfield). E.g. every new kind of
accomodation offering service goes into amenity (or was it tourism?).
Subtyping could be nice to have the information "facility offering a
place to sleep" in the main tag and "secondary" information like
hotel, guesthouse, etc. in additional tags (the same applies for
"eating and drinking" and a lot of others).

Another problem is tags that don't fit into the main tag. E.g. there
is Key:waterway which states: "Used to describe various waterway
features." Not very specific a definition, but still: How does a tag
"boatyard" fit into this?


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