Wikidata is very much a "working database". Its relevance is exactly because of this. Without the connection to the interwiki links, it would not be the same, it would not have the coverage and it would not have the same sized community.

Considerations about secondary use are secondary. Yes, people may use it for their own purposes and when it fits their needs, well and good. When it does not, that is fine too. As it is, we do have all kind of Wiki "junk" in there. We have disambiguation pages, list articles, templates, categories. The challenge is to find a use for them. 

When I add statements based on categories, I "document" many categories [1]. As a result over 900 items for categories will show the result of a query in the Reasonator. The results is what I think a category could contain given the subject of a category. For Wikipedians they are articles not categorised, red links and blue links.

There are several reasons why this is not (yet) a perfect fit. The most obvious one is including articles that are not part of the selection eg a list in a category full of humans. Currently not everything can be expressed in a way that allows Reasonator to pick things up in a query.. dates come to mind. Then there are the categories that have an "arbitrary" set of entries.

I am not going to speculate on what kind of qualifiers Commons will come up with. In essence when you can sort it / select it Wikidata will do a better job for you. The "only" thing we have to do is identify the items that fit the mold. This is something that you can often find the basis for in existing categories.

[1] http://ultimategerardm.blogspot.nl/2014/08/wikidata-my-workflow-enriching-wikidata.html

On 1 September 2014 00:42, James Heald <j.heald@ucl.ac.uk> wrote:
Hi everybody,

Sorry to open up an old thread again after ten days, but there were some things in Lydia's reply below that I wanted to come back to.

So, first, a couple of examples of the kind of Commons Categories I had in mind:



Despite their names, both these cats effectively identify images from particular photosets on Flickr.  The first category relates to a particular set of images released by a particular institution on a particular date.  The second relates to a particular set of scans from a particular edition of a particular book.  Both (IMO) would (and, moreover *should*) currently fail Wikidata:Notability.

The book, and even the edition, might be notable. But a particular set of scans surely would not. Similarly, the first category is really just a photoset from Flickr, again something that wouldn't currently get a Wikidata Q-number.

Now in the email below, Lydia effectively said: no problem, just give each Commons Category a Wikidata Q-number anyway.  ("Imho they should be on Wikidata. I fear if we introduce another layer it'll be considerably harder to use and maintain.")

GerardM, in sessions at Wikimania, also argued strongly simply for putting everything in Wikidata.

But I think this would be a mistake, because IMO Wikidata:Notability is a positive virtue, which should be defended.  It is *useful* to people that they can download a dump of Wikidata for their own purposes, and get real-world relevant items, rather than the dump being bloated with wiki junk.

So in my opinion, Commons categories should generally *not* get Q-numbers on Wikidata (unless they pass WD:N), but should instead get items on the Commons Wikibase which is being created expressly for the purpose of holding structured data on things which really only have a commonswiki significance, and are not real-world notable.

A second point relates to Magnus's issue about how much of this could be replaced by queries.

Yes, if one were progressively building up a topic search on images from books in the 1-million image BL Mechanical Curator release, one might ask for books about London, then books published in a particular date range.  But within that, the natural query to specify scans from this particular copy of 'Metropolitan Improvements' is the image's membership of this particular set -- membership of the set in itself is something that should be queryable, and such a query is the kind of query that, at the right stage, should be offerable to the user trying to refine their search.

In fact, most current Commons categories will not be WD-notable.  But even for the most egregious of Commons intersection categories, IMO it will still be worth the Commons Wikibase tracking category membership for an image, not least for the ability that will give to easily present the category's files in different ways -- eg perhaps sorted by filename; or by original creation date; or by upload date; or by uploader; or by geographical proximity... etc.  Holding the category membership in the wikibase then allows people to write gadgets to sort or filter or re-present the category in multiple ways.  So it's useful to have the category as an entity that can be a target for a property.

But there are also reasons for a category to have an item in its own right -- because there is structured data that one may wish to associate with the category:  one example would be access stats to members of the category (eg which categories in the Mechanical Curator collection have had the most file views?) -- the kind of thing of great interest to GLAMs.

Many categories also contain information defining them -- for example, for the book scans category, one would want a property that this category contained scans of the particular book (pointed to by its Q-number), probably a particular edition (probably a qualifier).  One might also want to associate linked data -- pointers to entries for the book in (possibly multiple) catalogues of its original host institution.

So for all these reasons it may well be useful, as a matter of course, to have a container for structured information associated with each commonscat.

This is why I think each and every category on Commons should have its own Commons Wikibase item, with an associated C-number.

Queries are important, but I'd suggest they are best seen as an *addition* to the present category system, rather than a *replacement* for it.

A particular way forward, it seems to me,  might be to allow categories to be *augmented* with specific queries -- i.e. to allow rules to be specified for particular categories, so that files whose structured-data topic information matched the rules would automatically be added to the categories, alongside the files already there.

Categories, including intersection categories, would therefore effectively auto-update, without human intervention, to include new files if they had appropriate topic information.

Existing legacy categorisation information would survive, allowing the new augmentation approach to slowly come into play if topic information were initially weak.  And categories should still be specifiable by hand (or automatically through templates, e.g. as source categories are often specified through source templates) -- because this can still be the most efficient way to specify naturally closed sets.

This would effectively allow a transition pathway towards categorisation / sets-of-interest becoming more determined by the structured data.

One thing in particular it could allow would be a gadget to highlight images that were in a category directly, *not* by virtue of any rule on any metadata, which could then allow such images to be investigated and/or have their topic metadata improved.

It's easy to mock the sometimes extraordinary depths of intersection categories on Commons; such intersection categories are a pain to determine for categorisation, not a very good fit for retrieval, and nor does it well match how the rest of the world does things, which makes metadata import harder and less effective than it should be.

But there are virtues in the category system too. There is a wealth of hard-won information encoded in it. And some categories do match natural groupings of images. The hand-curated category sets and hierarchies, reflecting context knowledge, will often do better than even the best AI-driven suggestions will ever be able to match for search refinement.

Such an approach as I've suggested above would combine categories and topics in an evolutionary rather than revolutionary way.  Categories would not all go away -- ever -- but would continue to exist side-by-side with topics in a symbiotic way, that IMO would make the transition smoother and more likely to engage and involve the existing community, to an end-point that it seems to me would have additional strengths over a pure query system.

I'm interested to know what other people think.

  -- James.  (User:Jheald)

On 19/08/2014 15:27, Lydia Pintscher wrote:
Hey :)

On Mon, Aug 18, 2014 at 4:22 PM, James Heald <j.heald@ucl.ac.uk> wrote:
Thanks Lydia!

Something that occurs to me is that one may well want to include Commons
categories in such a database, not just files, which presumably might be
stored on a page like

   Info:Category:Insert random Commons category intersection here

so that one could then ask whether a file belongs to such a category or not,
and the data would all be in the database.

So what you want is to be able to make the category one possible
search criteria when searching for images? We don't need an entity
type for that I think. We "just" have to build the search interface in
a way that it can take those into account as well from where they are
already now.
Or is that missing something important you had in mind?

Such categories (or sets) may well not be Wikidata notable, for example:

   Category:Pictures I took on my cellphone one midsummer morning

so we cannot assume they have Q-numbers.

My assumption so far was that we can assume every topic we use to tag
images to be in Wikidata. Are there some examples currently in use on
Commons that you think would not be covered? Because Wikidata will be
used to tag much more than just Commons images in the future. So we
should have a really huge vocabulary.

But it would be nice if we could describe such properties using the existing
Wikidata syntax, ie via a property Pxyz = "belongs to set", and then an item
number for the set it belonged to.

What set is this for example? Like "everything takes as part of Wiki
Loves Monuments 2012"? Or some other kind of set?

Since the items wouldn't be on Wikidata, it would be useful if they had a
different namespace,  eg   C nnnnnn

Imho they should be on Wikidata. I fear if we introduce another layer
it'll be considerably harder to use and maintain.


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