This is, admittedly, confusing and I still get tripped up by it. (In
fact, I just realized something I need to change _right now_).
Essentially, it's the distinction between information and
non-information resources:
http://www.rdfabout.com/intro/?section=8#Terminology
So, in this case you can't link to
"Italy--History--1492-1559--Fiction". That's not something that
exists on the web. It's an abstract concept. So the linked data
people came up with this convention for indirection using hashes.
So, the uri: http://id.loc.gov/authorities/sh2008115565 identifies a
web document that has information about a Library of Congress subject
heading.
http://id.loc.gov/authorities/sh2008115565#concept identifies the
concept "Italy--History--1492-1559--Fiction".
But they're different things.
dbpedia takes a different approach of using redirects from the URI.
So the URI for Italy is:
http://dbpedia.org/resource/Italy
if you load in your browser, you'll see:
http://dbpedia.org/page/Italy
and you had an RDF-aware browser (like, say, Redland's rapper), you'd
be redirected to:
http://dbpedia.org/data/Italy
Now, in the case of the conceptSchemes, Ed Jones found the RDFa
serialization, but you can see it as RDF/XML here:
http://www.w3.org/2007/08/pyRdfa/extract?uri=http%3A//id.loc.gov/authorities/
-Ross.
On Wed, Nov 11, 2009 at 2:39 PM, Jonathan Rochkind <rochkind_at_jhu.edu> wrote:
> I'm confused too. As I understand it, as far as RDF is concerned:
>
> http://id.loc.gov/authorities/sh2008115565#concept
>
> and
>
> http://id.loc.gov/authorities/sh2008115565
>
>
> are _different identifiers_. So either id.loc.gov is using different
> identifiers to refer to the same thing; in which case maybe this is
> accidental on id.loc.gov's part, or maybe there's a reason for that we don't
> understand. (There is in general no prohibition on using different
> identifiers to refer to the same thing, but it IS confusing. Using one
> identifier to refer to two different things, on the other hand, is
> prohibited). OR, those two URIs don't in fact refer to the same thing, they
> refer to two different things, but we don't understand what. OR we're just
> even more confused.
>
> We should ask Ed maybe? I am also confused. But personally hash URI's often
> confuse me.
>
> Jonathan
>
>
> Karen Coyle wrote:
>>
>> Quoting Jonathan Rochkind <rochkind_at_JHU.EDU>:
>>
>>
>>>
>>> Yeah, that's a confusing thing. The RDF world seems to like using hash
>>> URIs to represent things. As far as RDF is concerned, the URI's
>>> uniqueness is determined including the hash. Two URIs identical except
>>> that they end in two different hashes are two different identifiers as
>>> far as RDF is concerned.
>>>
>>
>> So in the example that Ross gave,
>>
>> <rdf:Description
>> rdf:about="http://id.loc.gov/authorities/sh2008115565#concept">
>>
>> identifies the same thing as:
>>
>> <rdf:Description rdf:about="http://id.loc.gov/authorities/sh2008115565">
>>
>> ?
>>
>> But
>>
>> <skos:inScheme
>> rdf:resource="http://id.loc.gov/authorities#conceptScheme"/>
>> <skos:inScheme
>> rdf:resource="http://id.loc.gov/authorities#geographicNames"/>
>>
>> do not either identify the same thing as:
>>
>> <skos:inScheme rdf:resource="http://id.loc.gov/authorities"/>
>>
>> ?
>>
>> If so, then, yes, that is very confusing.
>>
>
Received on Wed Nov 11 2009 - 15:13:47 EST