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Hi Kevin,<br>
<br>
Thanks for your thoughts. It does seem a bit of a hack the way I am
suggesting - more elegant solutions are welcome but I am not sure we
can get the hierarchy in the namespace.<br>
<br>
The classes would still be part of a regular inheritance hierarchy but
you wouldn't see it in the namespace.<br>
<br>
The only way you would see the hierarchy is if you had namespaces that
went something like this:<br>
<br>
<a class="moz-txt-link-freetext" href="http://rs.tdwg.org/ontology/BaseThing/MyClass/MySubclass/MySubSubClass/myproperty">http://rs.tdwg.org/ontology/BaseThing/MyClass/MySubclass/MySubSubClass/myproperty</a><br>
<br>
Kind of like an xpath down the hierarchy for every concept. I am not
sure how you would then handle targetNamespaces in XML Schema.<br>
<br>
I believe most people in the semantic world seem to have a namespace
per ontology and no indication of the class structure within the
ontology from the namespaces.<br>
<br>
I am curious about what a huge list of classes is - I have a general
question in the back of my mind about how big people think the TDWG
ontology needs to be. But that is a question for another day!<br>
<br>
Thanks,<br>
<br>
Roger<br>
<br>
<br>
Kevin Richards wrote:
<blockquote cite="mids519a01b.021@smtp.landcareresearch.co.nz"
type="cite">
<pre wrap="">My only thought is that it seems a bit like a hack and may be too
restrictive when trying to categorise classes. Ie it looks like you
intend to have ALL RDF classes under the namespace
<a class="moz-txt-link-freetext" href="http://rs.tdwg.org/ontology/">http://rs.tdwg.org/ontology/</a> (correct me if I am wrong). This will
result in a huge list of classes at the one level, and hence, again
diminishing the human readability of the ontology. I wouldnt know, but
it sounds like it also might cause ontology management headaches later
on?
Kevin
</pre>
<blockquote type="cite">
<blockquote type="cite">
<blockquote type="cite">
<pre wrap="">Roger Hyam <a class="moz-txt-link-rfc2396E" href="mailto:roger@tdwg.org"><roger@tdwg.org></a> 09/26/06 8:49 PM >>>
</pre>
</blockquote>
</blockquote>
</blockquote>
<pre wrap=""><!---->
Hi Everyone,
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: <a class="moz-txt-link-freetext" href="http://rs.tdwg.org/ontology/">http://rs.tdwg.org/ontology/</a>
Within the ontology we have a convention for concepts that goes like
this.
A class would be: <a class="moz-txt-link-freetext" href="http://rs.tdwg.org/ontology/tdwg123_MyClass">http://rs.tdwg.org/ontology/tdwg123_MyClass</a>
where 123 is the internal id of the class and MyClass is the class name
A property in MyClass would be:
<a class="moz-txt-link-freetext" href="http://rs.tdwg.org/ontology/tdwg123_myProperty">http://rs.tdwg.org/ontology/tdwg123_myProperty</a>
where 123 is the *class* id not the property id and myProperty is the
property name.
An instance would be <a class="moz-txt-link-freetext" href="http://rs.tdwg.org/ontology/tdwg123_789">http://rs.tdwg.org/ontology/tdwg123_789</a>
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
documents.
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.
Roger
Sally Hinchcliffe wrote:
</pre>
<blockquote type="cite">
<pre wrap="">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
</pre>
<blockquote type="cite">
<pre wrap="">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
<a class="moz-txt-link-freetext" href="http://tdwg.org/2006/03/12/TaxonNames">http://tdwg.org/2006/03/12/TaxonNames</a> does not resolve), I can only
</pre>
</blockquote>
</blockquote>
<pre wrap=""><!---->take
</pre>
<blockquote type="cite">
<blockquote type="cite">
<pre wrap="">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
</pre>
</blockquote>
</blockquote>
<pre wrap=""><!---->build a
</pre>
<blockquote type="cite">
<blockquote type="cite">
<pre wrap="">fully-qualified resource URI. A safer form of the above would be the
</pre>
</blockquote>
</blockquote>
<pre wrap=""><!---->
</pre>
<blockquote type="cite">
<blockquote type="cite">
<pre wrap="">fully qualified resource URI which looks like:
<tn:nomenclaturalCode
</pre>
</blockquote>
</blockquote>
<pre wrap=""><!---->rdf:resource=<a class="moz-txt-link-rfc2396E" href="http://tdwg.org/2006/03/12/TaxonNames/botanical">"http://tdwg.org/2006/03/12/TaxonNames/botanical"</a> />
</pre>
<blockquote type="cite">
<blockquote type="cite">
<pre wrap="">
-Steve
</pre>
</blockquote>
<pre wrap="">*** Sally Hinchcliffe
*** Computer section, Royal Botanic Gardens, Kew
*** tel: +44 (0)20 8332 5708
*** <a class="moz-txt-link-abbreviated" href="mailto:S.Hinchcliffe@rbgkew.org.uk">S.Hinchcliffe@rbgkew.org.uk</a>
_______________________________________________
TDWG-GUID mailing list
<a class="moz-txt-link-abbreviated" href="mailto:TDWG-GUID@mailman.nhm.ku.edu">TDWG-GUID@mailman.nhm.ku.edu</a>
<a class="moz-txt-link-freetext" href="http://mailman.nhm.ku.edu/mailman/listinfo/tdwg-guid">http://mailman.nhm.ku.edu/mailman/listinfo/tdwg-guid</a>
</pre>
</blockquote>
<pre wrap=""><!---->
</pre>
</blockquote>
<br>
<br>
<pre class="moz-signature" cols="72">--
-------------------------------------
Roger Hyam
Technical Architect
Taxonomic Databases Working Group
-------------------------------------
<a class="moz-txt-link-freetext" href="http://www.tdwg.org">http://www.tdwg.org</a>
<a class="moz-txt-link-abbreviated" href="mailto:roger@tdwg.org">roger@tdwg.org</a>
+44 1578 722782
-------------------------------------
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