[Tdwg-guid] Jena examples?

Steve Perry smperry at ku.edu
Tue Sep 26 16:15:52 CEST 2006

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 

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.


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 at rbgkew.org.uk

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