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Re: Different or same Namespace for SOSA/SSN

From: Rob Atkinson <rob@metalinkage.com.au>
Date: Thu, 09 Feb 2017 04:35:37 +0000
Message-ID: <CACfF9LxLLLGbYZdFQ6gaP0P9Ju+0b06FHC52Os=jZJ+dBqkKBA@mail.gmail.com>
To: janowicz@ucsb.edu, Simon.Cox@csiro.au, armin.haller@anu.edu.au, maxime.lefrancois@emse.fr, kerry.taylor@anu.edu.au, public-sdw-wg@w3.org
I agree that where an ontology defines terms, it should do so in adisctinct
namesapce and both the ontology and the namespace IRIs should dereference
to the same set of artefacts via content-negotiation.  This is standard
behaviour and shouldnt be a suprise to anybody.

There are additonal optional behaviours we could add, if we so desired:

1) asking for the SOSA ontology using OWL MIMEtype could return the SSN
Ontology - with its richer and SOSA-compatible axioms - BUT if SSN imports
SOSA this probably doesnt work, unless the import is a specific OWL
artefact URL (i.e. does not use the content-negotiation)
2) We could use "profiles" or linked data views or other modifiers on the
IRI to get compatible sub-or-supersets of an ontology - for example we
could get just SKOS view of the terms.

I dont think either of these options are part of the normative
specification - and in particular #2 could wait till a standard emerges,
but perhaps we should decide on whether #1 is useful and will help us cut
through the expectation.

Note that #1 works neatly for the three artefact solution - SOSA, SOSA with
OWL axioms, SSN extensions. if SOSA (content-type= owl+xml) ->
SOSA_with_OWL.rdf



On Thu, 9 Feb 2017 at 14:48 Krzysztof Janowicz <janowicz@ucsb.edu> wrote:

> 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 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
> <armin.haller@anu.edu.au>]
> *Sent:* Thursday, 9 February, 2017 10:47
> *To:* Maxime Lefrançois <maxime.lefrancois@emse.fr>
> <maxime.lefrancois@emse.fr>; janowicz@ucsb.edu; Kerry Taylor
> <kerry.taylor@anu.edu.au> <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>
> *Date: *Wednesday, 8 February 2017 at 9:16 pm
> *To: *Armin Haller <armin.haller@anu.edu.au>, "janowicz@ucsb.edu" <
> janowicz@ucsb.edu>, Kerry Taylor <kerry.taylor@anu.edu.au>, "
> public-sdw-wg@w3.org" <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> 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>
> *Date: *Wednesday, 8 February 2017 at 3:52 am
> *To: *"janowicz@ucsb.edu" <janowicz@ucsb.edu>, Kerry Taylor <
> kerry.taylor@anu.edu.au>, Armin Haller <armin.haller@anu.edu.au>, "
> public-sdw-wg@w3.org" <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> 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
> <armin.haller@anu.edu.au> <armin.haller@anu.edu.au>]
> *Sent:* Tuesday, 7 February 2017 3:09 PM
> *To:* 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
>
> Webpage: http://geog.ucsb.edu/~jano/
>
> 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
> Webpage: http://geog.ucsb.edu/~jano/
> Semantic Web Journal: http://www.semantic-web-journal.net
>
>
Received on Thursday, 9 February 2017 04:36:29 UTC

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