[OSM-dev] Restrict key names on order to retain reusability of OSM

Jochen Topf jochen at remote.org
Wed Feb 13 09:58:44 GMT 2008

I think the disagreement over the characters allowed in the tag keys
is because of different views, what the keys are:

Stefan sees keys as a sort of identifier, which makes sense from a
programmer point of view, thinking about hashes etc. It is also how many
other systems are structured as Stefan points out. So there is some kind
of attribute, which has an identifier as key and the data is in the

In the OSM world we see the key as data, too. There simply is no
identifier. Key and value both are considered data and so they need to
be unconstrained (or with as few constraints as possible). So
conceptually the key=value thing in OSM is much more just a convient
breakup of a single data entity than an identifier with a data value.

And while currently most keys have a simple form and are in English,
it will not be that way forever as the project gets more international
and people will start to add data that is more "local" in nature.

In Germany there is the word "Flurstück" (note the umlaut). Its a sort
of land parcel and it is used in the land registry. There is a very
specific definition for this word how it is used in the German land
registry and I rather suspect that definition is not in sync with
definitions for similar concepts in other countries. So I should be
allowed to use this exact word as a key instead of using some more
generic "lang_parcel" or something that might have different meanings in
different languages.

Jochen Topf  jochen at remote.org  http://www.remote.org/jochen/  +49-721-388298

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