[Tdwg-guid] Jena examples?
roger at tdwg.org
Tue Sep 26 10:49:03 CEST 2006
In the not very comforting words of software vendors these are "known
issues" and will be resolved in the next release ;)
But seriously.The namespaces in the TCS names vocabulary do not resolve
because we didn't have a policy at that time. The use if entity
references was 'borrowed' from an example (probably Protege output) and
I wouldn't mind doing away with it.
I have been thinking long and hard about the namespace issues in the
last few weeks and believe I have a solution that I will propose at TDWG
St Louis. It would be good to have face to face discussions about it and
make a decision there.
To briefly summarize: The issue is getting a namespace convention that
will work across technologies. Suppose we want to serve data in a
technology that "isn't very good at namespaces". As an example - if we
were to have separate namespaces for TaxonNames, TaxonConcepts,
Specimens, Metadata, GeospatialStuff, Collections and we wanted to
validate a document using XML Schema that contained all these things it
would require 6 independent schemas each with it's own target namespace.
If you have ever tried to debug something like this you will know what
total madness it is. We can't just abandon XML Schema because it would
rule out not only our existing technologies but GML and probably
others... It may also be desirable to express our ontology in things
that aren't even XML.
The only solution I can think is that for the TDWG Ontology we should
have a single formal namespace of: http://rs.tdwg.org/ontology/
Within the ontology we have a convention for concepts that goes like this.
A class would be: http://rs.tdwg.org/ontology/tdwg123_MyClass
where 123 is the internal id of the class and MyClass is the class name
A property in MyClass would be:
where 123 is the *class* id not the property id and myProperty is the
An instance would be http://rs.tdwg.org/ontology/tdwg123_789
where 123 is the *class* id and 789 is the instance id (there is nothing
stable about an instance that we could use as an identifier unless we
force a label property and make it immutable).
In a way this is using the part before the _ as a pseudo namespace.
I think this hits the balance between something that is technology
independent and something that will produce reasonably human readable
It is radical which is why I thought it would be good to talk about it.
Any one got an alternative?
We have to have a solution for this by the end of the St Louis meeting
as it is critical path for ontology work.
Most grateful for you patience and any thoughts you have.
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?
>> 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" />
> *** Sally Hinchcliffe
> *** Computer section, Royal Botanic Gardens, Kew
> *** tel: +44 (0)20 8332 5708
> *** S.Hinchcliffe at rbgkew.org.uk
> TDWG-GUID mailing list
> TDWG-GUID at mailman.nhm.ku.edu
Taxonomic Databases Working Group
roger at tdwg.org
+44 1578 722782
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