Another example of Wikidata + schema.org for type enumerations

Here's another example along the lines I sketched recently, after
sitting down with Denny today and looking at Wikidata. It is an
attempt to show how "types" handled externally from schema.org could
be written (in this case in RDFa) alongside basic schema.org types. We
revisit the use case of having more kinds of "place of workship" than
are anticipated in the schema.org core.

A couple of things to note about Wikidata first:

1. it does have basic properties for 'instance of' and 'subclass' but
there is no formal or software-backed understanding of these. Most of
Wikidata views these as simply more data about an entity. The Wikidata
software does not really have a notion of entities having types, this
is something added at a later level as data. Perhaps if type-like
constructs become common and popular in the community some UI or API
support might emerge (by very rough analogy, think about hashtags and
retweets in Twitter, which initially were also "just in the data").
I'll try to write type-like-entity instead of 'type' when talking
about Wikidata.

2. although the factual data in Wikidata is currently often fairly
thin, there are already many mappings to other identifiers, e.g. 1-2
million have Freebase links, which in turns brings in more factual
background data.

So here's an example, we describe the entity
https://www.wikidata.org/entity/Q2046262 (Pagoda Songyue) as falling
into the wikidata type-like-entity
https://www.wikidata.org/entity/Q199451 (Pagoda), and then anchor that
in the schema.org 'PlaceOfWorship' type.

<div vocab="http://schema.org/" typeof="PlaceOfWorship
https://www.wikidata.org/entity/Q199451">
  <span property="name">Pagoda Songyue</span>
   <span property="description">One of the few intact sixth-century
pagodas in China, located at the Songyue Monastery on Mount
Song.</span>
  <link property="url" href="https://www.wikidata.org/entity/Q2046262" />
  <link property="sameAs" href="https://en.wikipedia.org/wiki/Songyue_Pagoda" />
  <link property="sameAs" href="http://www.freebase.com/m/03bz2xf" />
  <div itemprop="geo" itemscope itemtype="http://schema.org/GeoCoordinates">
      <meta itemprop="latitude" content="34.501611" />
      <meta itemprop="longitude" content="113.015917" />
   </div>
 </div>

a) https://www.wikidata.org/entity/Q199451 is the type-like-entity,
"Pagoda" in Wikidata
b) https://www.wikidata.org/wiki/Property:P279 is the subClassOf
relation, ("all of these items are instances of those items; this item
is a class of that item").
c) https://www.wikidata.org/wiki/Q1370598 is "Place of Worship" in
Wikidata. This type-like-entity has associations with 'architectural
structure' and 'religion' within Wikidata. This would be the natural
place also to express a link to 'http://schema.org/PlaceOfWorship',
but that statement hasn't yet been expressed, and there might be some
details to work out on the mechanics.
d) https://www.wikidata.org/wiki/Property:P31 is the instanceOf
relation in Wikidata; ("this item is a concrete object (instance) of
this class, category or object group").


Last time I posted something in this direction (funeral homes,
http://lists.w3.org/Archives/Public/public-vocabs/2014Feb/0007.html)
there was a concern (Aaron's, in
http://lists.w3.org/Archives/Public/public-vocabs/2014Feb/0010.html )
that schema.org search engines might not care about other namespaces
so much. I'd like to explicitly set that aside for now, along with the
concern the lack of UI for these types. It's reasonable to ask
questions about both, but for now I'd like to concentrate on making
sure the representational machinery matches up.

>From looking at this today, it seems already possible to create
descriptions that draw on "types" from Wikidata alongside matching
broader types from schema.org. It seems possible within Wikidata to
talk about an entity being an "instance of" a type that shows up as
another entity within Wikidata, and for that type entity to have
subClass links to broader wikidata types. The Wikidata machinery (and
hopefully community process!) should also make it fairly easy to add
properties linking these type-like entities to other types such as at
schema.org, so that the wider community can keep collective notes on
the relationships between the type-like entitites Q1370598  and
Q199451 in Wikidata and schema.org's 'PlaceOfWorship' type.

In http://blog.schema.org/2012/05/schemaorg-markup-for-external-lists.html
a while back from schema.org, we wrote about the importance of
'external enumerations'. Wikidata barely existed back then. Now that
Wikidata is real, I'd like to encourage people to take a look. The
potential for combining Wikidata and schema.org is well worth some
thought...

Topic for another day: what do we do about enumerations where
instantiation-oriented type hierarchies are not a great fit?  There
are various properties in schema.org where we want to be more
structured than saying "values are a string or url", but where
schema.org as a project  doesn't directly want to draw up a list of
all the possible values. For example restaurant/menu cuisines  (e.g.
http://schema.org/servesCuisine http://schema.org/recipeCuisine) .
Let's come back to that one in the context of MiniSKOS. Wikidata may
have a role to play there too.

cheers,

Dan

ps. for more background on Wikidata, see Denny's recent article at
http://www.computer.org/portal/web/computingnow/content?g=53319&type=article&urlTitle=the-rise-of-wikidata

Received on Saturday, 22 February 2014 03:12:04 UTC