[OSM-talk] OSM relation ID property in Wikidata

[Peter Wendorff]

Am 07.05.2013 00:47, schrieb Tobias Knerr:
> Am 06.05.2013 23:55, schrieb Peter Wendorff:
>> Am 06.05.2013 23:07, schrieb andrzej zaborowski:
>>> If you're not adding those historical entities to OSM (or a similar
>>> database like that historical osm once discussed) then there's no
>>> issue with linking to Wikidata because there's nothing to be linked.
>>
>> Why not?
> 
> It wouldn't add any information. The hospital should be linked to the
> building _within_ Wikidata anyway because there are more properties that
> can be attached to a building than just a OSM building outline.
> 
> So if we connect the OSM building and the Wikidata building, then the
> hospital is already (though Wikidata) linked to the OSM building, too.
> 
>>> If it doesn't occupy the entire building then you can probably add the
>>> museum tag on the building geometry but later once you want to add a
>>> wikidata tag you'd probably split it out like you'd split a street
>>> object when you want to add an attribute that applies to a part of the
>>> attribute.  If you're into indoor mapping then you'd draw the museum
>>> outline separately anyway.
>> so you propose to split it up because of an external ID you propose to
>> add...
>> While I in general agree that objects of osm are split when they get
>> mapped in more detail (like in this example), I'm not happy to do that
>> for the reason to enable matching to external references.
> 
> Using the same OSM element for two distinct features actually
> contradicts a strict one feature, one OSM element principle. We do it
> anyway because it's convenient, but as soon as you want to add the same
> tag - whether it's name, opening_hours, or wikidata - to both features,
> you create two separate elements.
> 
> That's not a special treatment of external IDs, but consistent with
> other tags, and using two separate elements is semantically better anyway.

I agree from a theoretical point of view. But your failing assumption
here is, that wikidata only would link to perfectly fine mapped stuff.

If you would add that link to wikidata, you probably would divide it to
several osm objects before. But is that realistic to assume, that the
wikidata folks will do that, too?
This would require wikidata people to entirely know the osm model, how
to edit and what might be the drawback of combining features in one object.
And keep in mind it's not clear in every case what to separate and what
not.

regards
Peter