[Tagging] part_of:wikidata key

[Marc Gemis]

Do I understand it correctly that one of the reasons you do not want
to use Wikidata IDs because the data on the item is not verified
according to the same rules as OSM ?

For me Wikidata IDs can be viewed as URLs, just like the URL of a
shop. If I can verify that it describes the same item (more or less
(*)), I can add the Wikidata ID (or shop URL).

regards

m.

(*) Even URLs of hotels can describe too much (e.g. the environment,
things to see, etc.), but I haven't seen anyone complaining about
that.

On Wed, Nov 29, 2017 at 3:08 PM, Christoph Hormann <osm at imagico.de> wrote:
> On Wednesday 29 November 2017, Marc Gemis wrote:
>>
>> I assume you mean verifiable without accessing the Wikidata website.
>> I often hear contradicting information about "verifiable". Some
>> people say it's only "on the ground", others find it OK to ask
>> locals. It would be nice to know what you understand under
>> "verifiable".
>
> Verifiability ultimately has relatively little to with the sources used.
> On the contrary being independent of specific sources is a key aspect
> of it.
>
> For physically observable things this is pretty easy because it often
> boils down to if you can measure something - either directly as a
> quantity (like a geometry or the iconic height tag of a building) or
> using statistics (an area can qualify as natural=wood if it features a
> certain density of trees).  You can usually measure with better
> reliability and more accurately when you are locally on the ground so
> in cases of doubt the observation on the ground stands above remote
> assessment.
>
> For things like a name it is more complex because it is not usually
> observable physically - unless there are signs.  But you can verifiably
> determine the name of a lake for example by spending sufficient time
> around it and asking every local you meet for the name of the lake.  If
> you get consistent results (like 3/4 of the people giving you the same
> name) you have a verifiable name.  No one practically does this test of
> course but as a local mapper you have an intuitive feeling for what the
> test will have as results.
>
> Now the wikidata ID is different - not mainly because you have to look
> it up in a separate database (which you could argue is similar to the
> idea of asking a local for the name of something) but because what you
> look at there is not first hand local knowledge and because you cannot
> independently verify if this information is true or false.
>
> If i assume for a moment that every piece of information in wikidata is
> diligently recorded according to the rules there it would be possible
> to reconstruct this information from the "serious and publicly
> available references" used but in many cases it could *only* be
> reconstructed based on these sources and not independently.  This is
> the main reason why wikidata information is not verifiable according to
> the OSM understanding of verifiability.
>
> In other words: If a sufficient number of "serious and publicly
> available references" assert something is true this qualifies it for
> being recorded in wikidata.  So a lot of things in wikidata are not
> verifiable in the OSM sense because if they are true or false depends
> on what sources exactly you consider for your assessment.  And because
> of that the mapper in OSM cannot verifiably determine if a wikidata
> object created based on such information qualifies for being specified
> in a wikidata tag.
>
> --
> Christoph Hormann
> http://www.imagico.de/
>
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