This recent announcement by the Structured Data team perhaps ought to be quite a heads-up for us:
https://commons.wikimedia.org/wiki/Commons_talk:Structured_data#Searching_Co...
Essentially the team has given up on the hope of using Wikidata hierarchies to suggest generalised "depicts" values to store for images on Commons, to match against terms in incoming search requests.
i.e. if an image is of a German Shepherd dog, and identified as such, the team has given up on trying to infer in general from Wikidata that 'dog' is also a search term that such an image should score positively with.
Apparently the Wikidata hierarchies were simply too complicated, too unpredictable, and too arbitrary and inconsistent in their design across different subject areas to be readily assimilated (before one even starts on the density of bugs and glitches that then undermine them).
Instead, if that image ought to be considered in a search for 'dog', it looks as though an explicit 'depicts:dog' statement may be going to be needed to be specifically present, in addition to 'depicts:German Shepherd'.
Some of the background behind this assessment can be read in https://phabricator.wikimedia.org/T199119 in particular the first substantive comment on that ticket, by Cparle on 10 July, giving his quick initial read of some of the issues using Wikidata would face.
SDC was considered a flagship end-application for Wikidata. If the data in Wikidata is not usable enough to supply the dogfood that project was expected to be going to be relying on, that should be a serious wake-up call, a red flag we should not ignore.
If the way data is organised across different subjects is currently too inconsistent and confusing to be usable by our own SDC project, are there actions we can take to address that? Are there design principles to be chosen that then need to be applied consistently? Is this something the community can do, or is some more active direction going to need to be applied?
Wikidata's 'ontology' has grown haphazardly, with little oversight, like an untended bank of weeds. Is some more active gardening now required?
-- James.
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