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

From: Jeremy Tandy <jeremy.tandy@gmail.com>
Date: Thu, 01 Sep 2016 16:18:59 +0000
Message-ID: <CADtUq_0aFfMvYUet1jcPpXF7LnRB3GdQ=wkOxuihG5wWnMt-ig@mail.gmail.com>
To: Frans Knibbe <frans.knibbe@geodan.nl>
Cc: Simon Cox <Simon.Cox@csiro.au>, Joshua Lieberman <jlieberman@tumblingwalls.com>, SDW WG Public List <public-sdw-wg@w3.org>

I totally agree with your comments about being careful with <owl:sameAs>!

I've re-read the construction sector use case and think that this is
related to the topic that @robatkinson raised in his email [1]. See my
response [2].

I think that it is important that we can distinguish between the various
"representations" of a spatial thing - both when requesting a particular
representation from a server that can provide multiple representations or
when trying to determine what representation a server is able (or willing)
to provide.


[1]: https://lists.w3.org/Archives/Public/public-sdw-wg/2016Aug/0250.html
[2]: https://lists.w3.org/Archives/Public/public-sdw-wg/2016Sep/0018.html

On Thu, 1 Sep 2016 at 16:25 Frans Knibbe <frans.knibbe@geodan.nl> wrote:

> [snip]
>> 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
> <http://ontologydesignpatterns.org/wiki/Community:Overloading_OWL_sameAs>
> (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
> <http://w3c.github.io/sdw/UseCases/SDWUseCasesAndRequirements.html#ModellingInTheConstructionSector> was
> contributed, with its deriverd Subject equality requirement
> <http://w3c.github.io/sdw/UseCases/SDWUseCasesAndRequirements.html#SubjectEquality>
> .
> Regards,
> Frans
Received on Thursday, 1 September 2016 16:19:40 UTC

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