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Re: Example RDF linking species concepts to photo gallery RDF, Suggestions or Comments Appreciated

From: Peter DeVries <pete.devries@gmail.com>
Date: Fri, 8 May 2009 14:00:46 -0500
Message-ID: <3833bf630905081200n7c5adea9i930999980e35043a@mail.gmail.com>
To: Dan Brickley <danbri@danbri.org>
Cc: Toby A Inkster <tai@g5n.co.uk>, "public-lod@w3.org" <public-lod@w3.org>
Thanks Dan and Toby,
I had used the ontology for this, but after realizing that some ontologies
don't work well with others I thought it best to
be explicit in the data. Also, I did not want to require people to load my
ontology for this to work. I have done the same
with links with geonames etc. which you can see in the species and
observation examples below.

A mosquito species:

An observation of an American Toad:

I found this made my SPARQL queries work better, but it may be that I was
just not being clever enough in writing
my queries.

Sometimes I want *stateExpectedSpecies*, other times I want *
speciesExpectedInState*. Counties work the same way.

To be clear, the linkeddata recommendation is to not link back or that I
should need to make two predicates?


- Pete

On Fri, May 8, 2009 at 2:48 AM, Dan Brickley <danbri@danbri.org> wrote:

> On 8/5/09 09:14, Toby A Inkster wrote:
>> On 8 May 2009, at 01:30, Peter DeVries wrote:
>>  With the except of the predicates speciesHasGallery, galleryHasSpecies.
>> In <http://dig.csail.mit.edu/breadcrumbs/node/72> Tim Berners-Lee writes:
>>  On the other hand, also one should not encourage people having to
>>> declare both a property and its inverse, which would simply double the
>>> number of definitions out there, and give one more axis of arbitrary
>>> variation in the way information is expressed.
>> In other words, there isn't really a need to define both
>> speciesHasGallery *and* galleryHasSpecies. You only need one of them.
>> I've fallen into the trap of defining inverse properties before and when
>> it comes to actually working with the data (e.g. performing SPARQL
>> queries), it ends up complicating things.
> Yep. Historically, the asymetric nature of the RDF/XML serialization made
> inverses somewhat necessary, at least when aesthetic considerations were
> relevant to adoption. In fact some graphs (containing bnodes) couldn't be
> written in pre-RDFCore RDF/XML, until we added rdf:nodeID to the syntax.
> Even today, with rev="..." threatened in the HTML5 (re RDFa) world, that
> issue hasn't quite gone away. This is why FOAF has foaf:depiction and
> foaf:depicts, fwiw: some data is very image centric, and mentions of a
> person are an "in passing" matter. Other data is very person centric, and
> mention of images they're in is also something you do "in passing". So we
> had a fair amount of pushback when the RDF/XML required a whole separate top
> level element rather than a sub-element. You're right it makes more work for
> aggregators though.
> I've often thought of hacks like canonicalising on load, eg. by chosing the
> alphabetically 1st one of the two inverses. But then I get to thinking, ...
> couldn't the SPARQL engine just handle that.
> So ... what's the state of play w.r.t. SPARQL systems having the smarts to
> understand OWL inverse properties?
> Dan

Pete DeVries
Department of Entomology
University of Wisconsin - Madison
445 Russell Laboratories
1630 Linden Drive
Madison, WI 53706
Received on Friday, 8 May 2009 19:01:26 UTC

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