[OSM-talk] Could we just pause any wikidata edits for a month or two?

[Christoph Hormann]

On Wednesday 11 October 2017, Minh Nguyen wrote:
> Great questions. I've attempted to answer a few of them below:

Thanks for the effort - but from my point of view these answers mostly 
do not actually address the key points of my questions.  

I have made some progress getting answers to some of the core questions 
on the German forum 
(https://forum.openstreetmap.org/viewtopic.php?id=59910&p=3) so far 
resulting in the following conclusions from my side.

* stability of Wikidata IDs seems limited.  There seems to be a concept 
of redirects so an ID can point to a Wikidata object with a different 
ID and the object formerly under that ID is not necessarily identical 
to the one it redirects to.  To what extent re-structuring of 
information on Wikidata (that would primarily mean merging and 
splitting of Wikidata objects) leading to the creation of redirects 
happens and how much more or less common it is to OSM IDs changing i 
don't know (and given Wikidata is still very young such information 
would also be quite unreliable for the future).

* there definitely is no 1:1 relationship between Wikidata IDs and OSM 
objects in general.  In particular this is not the case for Wikidata 
objects covering several concepts that are separately mapped in OSM 
(where several features in OSM correctly refer to the same Wikidata 
ID).  Also in case of redirects in Wikidata there would be several 
Wikidata IDs corresponding to the same OSM feature (although you could 
of course formally define redirects as invalid Wikidata IDs - which 
however would further limit the stability of those IDs as explained 
above).

* Wikidata is definitely not suited as an universal meta-database 
connecting OSM with other open data sets.  This is because of the 
Notability concept (https://www.wikidata.org/wiki/Wikidata:Notability) 
which practically means the vast majority of the >500 million tagged 
features in OSM will never be able to get a Wikidata ID and will 
therefore never be able to be connected to other data sets through 
Wikidata.

There are still a lot of things that are unclear to me about the 
whole "Wikidata in OSM" subject so any further insights into this are 
welcome.  Given that Wikidata cannot function as an universal connector 
of OSM to other databases (something i was not really aware before) i 
would in particular like to re-emphasize the question:

> * What is the qualification of Wikidata for having its IDs in OSM
> (both for wikidata=* and X:wikidata=*)?  Is there a particular
> objective criterion that qualifies it?  Would there be other external
> IDs that would also qualify under these criteria?  Is there a limit
> in the number of different external IDs OSM is going to accept?

Please understand that from my side this is truly an open question, not 
a means to press for removing wikidata IDs from OSM.  But it is a 
question that needs a good answer from my point of view.  And 
deflecting by pointing to other IDs we already have in OSM like 
leftovers from imports and IDs for specific real world uses does not 
really help here.

> > * To what extent has there been information transferred
> > systematically from Wikidata and Wikipedia to OSM based on wikidata
> > ID references (like adding names in different languages).  As
> > others have explained this would be legally problematic and it
> > would be important to know how common this is.
>
> I agree that there are questions about OSM's acceptance of labels and
> statements copied from Wikidata, though I would've expected this
> phenomenon to be at least as common with Wikipedia long before the
> introduction of the wikidata tag.

But my question was specifically to what extent data has been 
transferred based on wikidata ID references.  The question if such data 
transfer happened before based on other connections has nothing to do 
with this.

We definitely have under-the-radar data imports from Wikidata, sometimes 
partly disguised by moving nodes - but the names matching in all 
inconsistencies is a clear indicator.  Like here:

http://www.openstreetmap.org/node/4996439821
http://www.openstreetmap.org/node/5073632521
http://www.openstreetmap.org/node/5121933121

But this is also a different matter unrelated to the Wikidata IDs in 
OSM.

-- 
Christoph Hormann
http://www.imagico.de/