[OSM-dev] Using relations to save data

[Roland Olbricht]

Am Dienstag, 4. Mai 2010 22:12:02 schrieb Andreas Kalsch:
> I am still reading some old mailing list posts ...
> 
> What about a relation with type="data", which is a relation that can
> include tags and other relations recusively?

It is a really good idea to store definitions of tags directly into the 
database, but relations leave some drawbacks open:

- A description might easily surpass 255 characters. Or you might want to use 
markup (e.g. for a link or for emphasizing things).

- Often tags apply only to a part of the world. Or, even worse, do have 
different meanings in different part of the worlds. Think of different 
maxspeed restrictions on motorways in different parts of the world.

I'd encourage you to start using those relations now but we should have a more 
versatile solution with the next API. See 
http://wiki.openstreetmap.org/wiki/API_v0.7#Classes

> > [1]http://www.remote.org/frederik/tmp/towards-a-new-data-model-for-osm.pdf

Looks interesting. But I thin it is largely outdated because it does not 
consider relations. And, of course, a couple of new problems have arisen in 
the meantime.

How about starting an updated version of that paper somewhere in the wiki or 
elsewhere?

Cheers,

Roland