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RE: Different or same Namespace for SOSA/SSN

From: Kerry Taylor <kerry.taylor@anu.edu.au>
Date: Thu, 9 Feb 2017 05:14:30 +0000
To: "janowicz@ucsb.edu" <janowicz@ucsb.edu>, "Simon.Cox@csiro.au" <Simon.Cox@csiro.au>, Armin Haller <armin.haller@anu.edu.au>, "maxime.lefrancois@emse.fr" <maxime.lefrancois@emse.fr>, "public-sdw-wg@w3.org" <public-sdw-wg@w3.org>
Message-ID: <SYXPR01MB1536C404B80838E882C546A7A4450@SYXPR01MB1536.ausprd01.prod.outlook.com>
Responding to Simon’s question:
>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?

Not necessarily in any order:
(0): Are you sure about SKOS having multiple namespaces? – I don’t think so http://www.w3.org/2004/02/skos/core#

(1):  Well DC is not exactly a practice we would like to follow. – the multiple namespaces are shockingly confusing (my view).
(2)  PROV, otoh would have greatly benefited from some modularity  in practice  that supported  the modularity it claims  in documentation. We can do better.
(3) We have the opportunity here to get “modularisation” right – I think it was Josh that expressed his hope to have it as the most important outcome of the group!
(4) We know a scalable way to have as many separate ontology modules/graphs/files interacting as we wish --- great design for “modularity”. By using the term-at-a time  rewrites to map each term to  the ontology module that introduces it in its most simple form.  We can direct the term resolving to the “easiest” place.
(5) By this method sosa users will get exactly  the behaviour the practitioners are used to.  You can get the sosa ontology from a sosa uri. You can resolve any sosa term in the namespace in the usual way – and get straight back to the sosa ontology (or the namespace doc , as convention dictates).
(6) Only more sophisticated ssn users would see any difference to the norm.  If you are looking at the ssn ontology and you  resolve a term that is not in sosa then you get the ssn full ontology – standard expected behaviour, surely!  But if you resolve a term that is first introduced in sosa you get the sosa core –this is the only case that might be surprising – but it is a case for those who know what they are doing and looking for.
(7) Branding?  Not  an issue as far as I know. “ i.e., a clear signal that SOSA is usable on its own. “ . Conflating matters. A “clear signal that sosa is usable on its own” is much more clearly sent in other ways
(8) texttt{sosa:sensor}: Such a corner use case in an academic presentation?  (and not an argument  I have ever met before!) Irrelevant  in most cases because the term means the same thing whichever ontology URI you find it in, by design.

-Kerry
From: Krzysztof Janowicz [mailto:janowicz@ucsb.edu]
Sent: Thursday, 9 February 2017 2:49 PM
To: Simon.Cox@csiro.au; Armin Haller <armin.haller@anu.edu.au>; maxime.lefrancois@emse.fr; Kerry Taylor <kerry.taylor@anu.edu.au>; public-sdw-wg@w3.org
Subject: Re: Different or same Namespace for SOSA/SSN

Thanks Simon, I fully support and agree with everything what you said.

Let me just add two more aspects.

One is the branding, i.e., a clear signal that SOSA is usable on its own.

Secondly, and more importantly, what about academic papers, documentations, slides, source code fragments, and so forth. Clearly, if I have a code snippet, slides, or a text fragment in a paper (such as "Lorem ipsum dolor sit amet, consectetur adipiscing elit \texttt{sosa:sensor} Duis sed sollicitudin metus, eu vulputate magna.") then two namespaces are easier to use while a one namespace solution suddenly becomes a problem if I would like to immediately know which of the two ontologies are being used.

Best,
Jano



On 02/08/2017 04:52 PM, Simon.Cox@csiro.au<mailto:Simon.Cox@csiro.au> wrote:
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?

Simon



From: Armin Haller [mailto:armin.haller@anu.edu.au]
Sent: Thursday, 9 February, 2017 10:47
To: Maxime Lefrançois <maxime.lefrancois@emse.fr><mailto:maxime.lefrancois@emse.fr>; 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>
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,
Maxime

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:
Sanity-checked!

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

Hi,

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:

https://www.w3.org/2015/spatial/wiki/NamespaceIssue


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,
Armin




--

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/<http://geog.ucsb.edu/%7Ejano/>

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





--

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 05:15:13 UTC

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