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Re: Clarification required: BP6 "use HTTP URIs for spatial things"

From: Frans Knibbe <frans.knibbe@geodan.nl>
Date: Thu, 1 Sep 2016 17:25:08 +0200
Message-ID: <CAFVDz42KOm7dbM21_Vmhdony0xK1QYaEEyii+BFbMj=aUbEFGw@mail.gmail.com>
To: Jeremy Tandy <jeremy.tandy@gmail.com>
Cc: Simon Cox <Simon.Cox@csiro.au>, Joshua Lieberman <jlieberman@tumblingwalls.com>, SDW WG Public List <public-sdw-wg@w3.org>

> It is tricky - I've been confusing myself for the last couple of days at
> least! So if we _do_ conflate the real world thing (e.g. Eddystone
> Lighthouse) and the discerned feature (e.g. Eddystone Lighthouse seen as
> a vertical obstruction) then it would be acceptable to use <owl:sameAs>
> with no need for the "sameRealWorldEntityAs" property; e.g. ...
>     <http://example.com/sar/features/vo/EDY> owl:sameAs <
> http://example.org/maritime/navaid/2650253> .
> This would align with the common approach used in Linked Data where
> (authoritative) identifiers are reused across different domains, datasets
> and applications with the view to providing common "nodes" in the
> "knowledge graph". The BP doc actively encourages such reuse of identifiers
> (assuming that the data publisher / curator can be 100% sure that the
> identifier identifies the thing they're making statements about!). For
> example, we might want to encourage folks to reuse the identifier for
> Eddystone Lighthouse minted by Google for the Knowledge Graph: <
> https://g.co/kg/m/013qr8> (which I think is derived from an older
> Freebase identifier)
> If I've interpreted correctly (as above), then I will try to include a
> Note in the BP document alluding to feature discernment and the related
> cognitive process.
> Jeremy

We have to be very careful with recommending owl:sameAs for identifying
equivalence of resources (individuals). This page
(Overloading OWL sameAs) summarizes discussion about owl:sameAs in the
semweb community years ago and it specifically says that linking a thing
with data about that thing with owl:sameAs is abuse of owl:sameAs.

The paper When owl:sameAs isn't the Same: An Analysis of Identity in Linked
Data <https://www.w3.org/2009/12/rdf-ws/papers/ws21> goes further and says
that when two resources are linked by owl:sameAs they are expected to have
the same properties, and "[..] any statement that is given to a single URI
is true for every other URI that has an owl:sameAs link".

The reason that a satisfactory solution to asserting resource equivalence
did not seem available on the web was the reason the use case Modelling In
The Construction Sector
contributed, with its deriverd Subject equality requirement

Received on Thursday, 1 September 2016 15:25:40 UTC

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