[Tagging] Part/whole confusion with Wikidata tag, and the need for enveloping parts into a whole

Christoph Hormann osm at imagico.de
Tue Aug 7 08:00:40 UTC 2018

On Monday 06 August 2018, peterkrauss wrote:
> Seems a commom quality problem of part/whole confusion in the
> Wikidata attribution or OSM's POI reference... And where there are a
> need for "enveloping parts into a whole".
> [...]

The fact that there is no agreement on the nature of the relationship 
between Wikidata objects and OSM objects has been an important point of 
critique of the whole 'adding wikidata IDs to OSM' movement.  You can 
read this up in the previous discussion here and in talk.

OSM aims to map based on local verifiability.  Therefore many things we 
map in OSM have no equivalent in Wikidata (because they do not satisfy 
the criteria for inclusion there) and many things in Wikidata cannot be 
mapped verifiably in OSM.  And inventing some kind of collector 
relation that collects all objects that by some wikidata 
interpretation 'belong to' a certain Wikidata ID and thereby implements 
a 1:n relationship would not change that (it would just be pointless 
non-maintainable, non-verifiable dead weight in the database).

My favourite example for this is the Amazon rainforest (but you can use 
other large eco-regions like the Sahara desert as well).  You won't be 
able to verifiably map the Amazon rain forest in OSM as an entity.  
What we aim to do in OSM is to accurately map the woodlands of South 
America - which is still a very long way to go.  But if this should 
happen it will happen locally because natural=wood/landuse=forest is 
locally verifiable while the abstract concept of naming some of this 
woodland the Amazon rainforest is not.

Christoph Hormann

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