User:Yurik/Wikidata OSM questions

= Questions =

General

 * Same WP/WD tags on relation and on member ways
 * Same WP/WD tags on relation and on member nodes. For example, the relation with the city boundary and city center node has the same tag as the center node.
 * Same WP/WD tags on relation and on super relations

Rivers

 * a river could consist of multiple relations (multipolygon water and waterways) and simple ways

Maritime borders

 * Some objects have both maritime and coastal borders. Which should have WP/WD tags?

Tunnels

 * Some tunnels are marked with  and also have   tag that sometimes match (and I feel should be deleted), or when it doesn't, it is due to main tag describing the whole route rather than the way portion. I suspect it should be using relation instead.

Dealing with "wikipedia" tags when there is no perfect match
Sometimes, Wikipedia tag does not point to a perfect 1:1 -- a Wikipedia page often describes more than one OSM object. OSM has  and other tags to indicate that the article is not about the object, but instead only relates to the object, but we may need to expand that:
 * Wikipedia tag points to a list of locations, e.g. list of subway yards or list of cathedrals
 * Wikipedia tag points to a redirect, that in turns point to a list, e.g. Concourse Yard
 * Wikipedia tag points to an anchor within an article (similar to above, but the "#' is explicit in the tag value)
 * Wikipedia tag points to a concept larger than the object, e.g. there is a "historical" (area + city center) and "administrative" (area without city center) boundary of a parish, but both use the same article about the parish.

Data quality benefits

 * Get all Wikipedia links in all languages for a given object
 * In case a Wikipedia article is renamed or deleted, Wikidata is more likely to stay intact. It will link to other languages or simply provide a placeholder for the future articles.
 * Easier to validate Wikipedia links, e.g. detect that link points to a disambiguation page instead of a place page when the original wiki page got renamed
 * Easier to validate administrative boundaries and admini_levels, to see that both Wikidata and OSM area hierarchy matches


 * Add multilingual names to any OSM objects

Usage benefits

 * Wikipedia can show object outline in various articles based on Wikidata ID