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RE: Different or same Namespace for SOSA/SSN

From: <Simon.Cox@csiro.au>
Date: Thu, 9 Feb 2017 00:52:57 +0000
To: <armin.haller@anu.edu.au>, <maxime.lefrancois@emse.fr>, <janowicz@ucsb.edu>, <kerry.taylor@anu.edu.au>, <public-sdw-wg@w3.org>
Message-ID: <cfec53e030d94a868d2558b273eada05@exch1-mel.nexus.csiro.au>
On ISSUE-80 and https://www.w3.org/2015/spatial/wiki/index.php?title=NamespaceIssue

I can see that the http knitting described by Maxime is a very clever technical solution which might allow use of a single namespace.
But I am very concerned that it deviates significantly from conventional expectations.

The goals of the SDW working group are primarily to make spatial data more visible on the web.
In my opinion we should be very cautious about using techniques which, while technically and theoretically defensible, would surprise time-strapped/lazy web developers and users, and lead them to just go somewhere else.

SSN has had enormous impact in the research community, is cited in a lot of journal papers, but very little outside that milieu.
SOSA is carefully pitched at a broader community, which we generally characterize as the ‘schema.org’ community.
It includes a limited subset of the classes and properties that are required for the whole story, but is still consistent with (a slightly revised version of) SSN, with the expectation that it can therefore serve as its core.
We anticipate use by people who don’t know or care about semantics and entailments and property-chain axioms and the like, but would be happy to tag data using URIs from a coherent set with a coherent identity.

The theory says that namespace != file != ontology != graph
But the practice and common usage and expectations don’t follow the theory, and frankly it is folly to imagine the world is going to change to suit our refined needs.
We know for starters that a separate URI is needed for each graph, and in practice these are expected to also correspond with an ontology URI and then for practical reasons to the namespace for individual items originally defined within the ontology.

I really don’t think a single namespace URI for two different products passes the Pareto principle, even if one builds on the other.
And certainly not the laugh-test.

What exactly is the objection to two namespace URIs? We wouldn’t be the first to go this direction for a core and extensions: Dublin Core, SKOS both have them, and it is a standard tool for both re-use and modularization. Is it essentially around branding?


From: Armin Haller [mailto:armin.haller@anu.edu.au]
Sent: Thursday, 9 February, 2017 10:47
To: Maxime Lefrançois <maxime.lefrancois@emse.fr>; janowicz@ucsb.edu; Kerry Taylor <kerry.taylor@anu.edu.au>; public-sdw-wg@w3.org
Subject: Re: Different or same Namespace for SOSA/SSN

ISSUE-80 is specifically addressed towards the namespace issue. The two proposals are very similar, but have been a point of contention for some. Whatever we chose, does not impact further integration issues, mainly the unresolved issue if we either reuse URIs only (and narrow their semantics) or use equivalence/sub-class relations in SSN.

We were working through Kerry’s architecture proposal in our telco on the 31st of January https://www.w3.org/2017/01/31-sdwssn-minutes  where we got stuck on the URIs, the ontology file (which has been resolved since) and the namespace. If we have a consensus in our next meeting, I will propose to close ISSUE-80. We still have the more general integration issues pending, i.e. https://www.w3.org/2015/spatial/track/issues/115 and https://www.w3.org/2015/spatial/track/issues/139.

From: Maxime Lefrançois <maxime.lefrancois@emse.fr<mailto:maxime.lefrancois@emse.fr>>
Date: Wednesday, 8 February 2017 at 9:16 pm
To: Armin Haller <armin.haller@anu.edu.au<mailto:armin.haller@anu.edu.au>>, "janowicz@ucsb.edu<mailto:janowicz@ucsb.edu>" <janowicz@ucsb.edu<mailto:janowicz@ucsb.edu>>, Kerry Taylor <kerry.taylor@anu.edu.au<mailto:kerry.taylor@anu.edu.au>>, "public-sdw-wg@w3.org<mailto:public-sdw-wg@w3.org>" <public-sdw-wg@w3.org<mailto:public-sdw-wg@w3.org>>
Subject: Re: Different or same Namespace for SOSA/SSN

Please, I would like us to wait and keep ISSUE-80 open for until the integration process is complete,

As you may have noticed, these two proposals are very, very similar technically.
It would be quite easy to swap from one to another.

So would I suggest we keep using two different namespaces for now, and discuss *once the integration process is complete* the pro and cons of these different solutions.
I don't think most of the participants get the full picture and implications of one or the other solutions anyways, for now.

Kind regards,

Le mer. 8 févr. 2017 à 04:44, Armin Haller <armin.haller@anu.edu.au<mailto:armin.haller@anu.edu.au>> a écrit :
Thanks Maxime for the additions to the Wiki!

I think this is now very detailed and we can proceed to vote on the last part of the issue embedded in ISSUE-80 https://www.w3.org/2015/spatial/track/issues/80. Are we using one unifying namespace or are we using different namespaces in our next telco.

From: Maxime Lefrançois <maxime.lefrancois@emse.fr<mailto:maxime.lefrancois@emse.fr>>
Date: Wednesday, 8 February 2017 at 3:52 am
To: "janowicz@ucsb.edu<mailto:janowicz@ucsb.edu>" <janowicz@ucsb.edu<mailto:janowicz@ucsb.edu>>, Kerry Taylor <kerry.taylor@anu.edu.au<mailto:kerry.taylor@anu.edu.au>>, Armin Haller <armin.haller@anu.edu.au<mailto:armin.haller@anu.edu.au>>, "public-sdw-wg@w3.org<mailto:public-sdw-wg@w3.org>" <public-sdw-wg@w3.org<mailto:public-sdw-wg@w3.org>>
Subject: Re: Different or same Namespace for SOSA/SSN

Sure !
I think we agreed on this before ...

Le mar. 7 févr. 2017 à 17:45, Krzysztof Janowicz <janowicz@ucsb.edu<mailto:janowicz@ucsb.edu>> a écrit :
Just to make sure, in all cases we assume that there are two separate files and two separate URLs.

On 02/07/2017 06:58 AM, Kerry Taylor wrote:

From: Armin Haller [mailto:armin.haller@anu.edu.au]
Sent: Tuesday, 7 February 2017 3:09 PM
To: public-sdw-wg@w3.org<mailto:public-sdw-wg@w3.org>
Subject: Different or same Namespace for SOSA/SSN


I have made an attempt to showcase the implementation of using different or the same namespace for SOSA and SSN on a new wiki page:


Currently we have an implementation that follows the two namespace proposal.

Can I ask, in particular, the advocates of only having one namespace for SOSA/SSN to sanity-check the implementation option on the Wiki. As this is rather unusual ontology design, I don’t know if I have captured the intention correctly.

Kind regards,


Krzysztof Janowicz

Geography Department, University of California, Santa Barbara

4830 Ellison Hall, Santa Barbara, CA 93106-4060

Email: jano@geog.ucsb.edu<mailto:jano@geog.ucsb.edu>

Webpage: http://geog.ucsb.edu/~jano/

Semantic Web Journal: http://www.semantic-web-journal.net

Received on Thursday, 9 February 2017 00:53:42 UTC

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