Hi Steve/all
I agree that we should start trying to nail down the TCS/RDF more
firmly. I know that Roger wants to discuss this at TDWG but I think
some firm proposals are needed to take to the meeting - and some
robust examples as well, for those of us who struggle with RDFS, OWL
et al and need to see actual implementations to properly engage with
the proposals. Otherwise, as you say, we will end up with some de
facto standards based on LSID implementations which were never
intended to be anything more than proof of concepts.
Now is a good time to tackle this for us, because we're re-opening
the LSID implementation that we did for IPNI and trying to bring it
up to something that will be properly releasable and can be more
widely publicised. As part of that work it will be easy to make any
changes to the metadata that's produced. Once released, pressures of
time and other projects will make it hard to re-open the work and
change the metadata output.
Is TAG the best place to discuss this? I'm not on that mailing list
but I can probably join if the discussion is going to be over there.
Let me know
Sally
Hi Sally,
No problem. The task was to create a prototype LSID resolver, not to
solve all the KR issues surrounding taxon concepts. However, I do think
it's time we start talking about these issues. I worry that the
prototype resolvers we set up will become de facto reference
implementations, that other people will start to construct services
modeled on the prototypes without us ever having gone back to talk about
what worked and what didn't.
I know there are several versions of TCS-in-RDF floating around. I
think Roger's is an RDFS document. Rob Gales created an OWL-DL version
for the GBIF demonstration project that Jessie and he worked on this
summer. Early this year I created a partial implementation in OWL-Lite
(that I've since discarded). While each one is "TCS", they're all
substantially different in the way they represent TCS classes and
properties, in part because the different representation languages
(RDFS, OWL-Lite, OWL-DL) have different language features and expressive
powers.
It would be nice if we could devise one standard RDF implementation of
TCS. I don't care which one we use, but I would like to narrow the
field to one so we can get the details sorted out. I'm talking about
details like resolvable namespaces, typed versus non-typed literals, the
use of anonymous resources, and serialization issues like the
references-to-resources problem that cropped up in the IPNI example
Peter Hollas is working from. These details are quite important because
certain decisions taken here can effect the larger network of linked
data providers.
Take the anonymous resources issues: If you look at the example Peter
cites, the typifiedBy property refers to an anonymous NomenclaturalType
that has a dc:title. Within a single data provider, this is no big deal
because many different data objects can refer to this
NomenclaturalType. However the use of anonymous resources can cause big
problems when you try to harvest and index the data from multiple
providers. It also causes problems for the caching use case.
It would be nice to discuss some of these things, perhaps within TAG.
-Steve
Sally Hinchcliffe wrote:
Hi Steve /all
We took that syntax straight from Roger's RDF/TCS examples. I think
Roger was going to do more work on tidying up those sorts of loose
ends. I have to admit that my knowledge of RDF and particularly RDFS
is pretty superficial
We can switch to either the shorter format or the safer fully
qualified URI - what do people think would be better?
Sally
By the way, the IPNI example you cite has an error:
<tn:nomenclaturalCode rdf:resource="&tn;#botanical" />
Many RDF/XML parsers will see &tn; as an entity which cannot be
resolved. Since I don't have a copy of the ontology (and
http://tdwg.org/2006/03/12/TaxonNames does not resolve), I can only take
a guess that it should look something like:
<tn:nomenclaturalCode rdf:resource="tn:botanical" />
However, using XML namespace prefixes in resource references inside
RDF/XML documents tends to cause problems because not all RDF/XML
parsers are smart enough to dereference the namespace prefix and build a
fully-qualified resource URI. A safer form of the above would be the
fully qualified resource URI which looks like:
<tn:nomenclaturalCode rdf:resource="http://tdwg.org/2006/03/12/TaxonNames/botanical" />
-Steve
*** Sally Hinchcliffe
*** Computer section, Royal Botanic Gardens, Kew
*** tel: +44 (0)20 8332 5708
*** S.Hinchcliffe@rbgkew.org.uk
*** Sally Hinchcliffe
*** Computer section, Royal Botanic Gardens, Kew
*** tel: +44 (0)20 8332 5708
*** S.Hinchcliffe@rbgkew.org.uk
_______________________________________________
TDWG-GUID mailing list
TDWG-GUID@mailman.nhm.ku.edu
http://mailman.nhm.ku.edu/mailman/listinfo/tdwg-guid