VIAF as linked data

Update 2010 May:  See a more recent post about VIAF and linked data: http://outgoing.typepad.com/outgoing/2010/05/viafs-new-linked-data.html.

As promised in an earlier post, VIAF (the Virtual International Authority File) is now available as linked data. For those not familiar with VIAF, it is a merger of nearly 20 national-level name authority files (currently we are only dealing with personal names).  There are some 9.5 million personae described in VIAF and have established more than 4 million links between the files.

To us linked data means:

• URIs for everything
• HTTP 303 redirects for URIs representing the personae our metadata is about 
• HTTP content negotiation for different data formats
• An RDF view of the data
• A rich a set of internal and external links in our data

Here are some example URIs for Lorcan Dempsey in VIAF:

• The canonical VIAF record: http://viaf.org/viaf/3697804
• A MARC -21 version: http://viaf.org/viaf/36978042.m21
• UNIMARC: http://viaf.org/viaf/36978042.unimarc
• RDF: http://viaf.org/viaf/36978042.rdf
• The persona being described: http://viaf.org/viaf/36978042.rwo

In addition to using the extensions (e.g. m21), HTTP content negotiation can be used to get the various versions of the record. 

The canonical URI currently returns an XML version of the VIAF record (which gets rendered into HTML in the browser via XSLT), but in the future we expect to return HTML.  As more of the authority files contributing to VIAF become available on the web we will be including more links to external sites.

For RDF we are currently returning a fairly rudimentary Friend of a Friend (FOAF) record.

The design and implementation of VIAF's linked data was done by Ralph LeVan.

--Th

Comments

[Bruce]

This is really nice Thom!

One comment on the FOAF, though: the foaf:name property is really for the display form of the name, but you're using it for effectively a semi-structured representation of the sort form. Is this something you might work on over time?

[Thom]

I see the VIAF FOAF as primarily a place holder for what might be done in the future, so we're open to suggestions on how it could be improved, especially from someone that would make use of it.

--Th

[Patrick Danowski]

Hi Thom,
Can you provide the ID Numbers of the Person in the different Authority files in the RDF? Or a possibility to get to the page if i know for example the PND Number of the national library. The VIAF is not very much used this would it make easier creating links to VIAF from other sources like the German set of dbpedia (i a lot of wikipeda articled the PND Number is inside.

Just a few ideas for improvement.

Response: That sounds like a reasonable thing to do. Any idea how you would like the RDF to look?
--Th

[Joachim Neubert]

Hi Thom, hi Ralph,

It's great to see VIAF taking the way to linked data. Millions and millions of well-defined entities for author disambiguation are a real treasure, for bibliographic applications as well as for the Linked Data Web as a whole.

I played with your website using the URIs you gave and had a conversation with Richard Cyganiak from http://pedantic-web.org about it. Richards hints had proved very helpful when I built my own Linked-Data application (at http://zbw.eu/stw). He pointed out an issue I observed on viaf.org but could not explain. When asking

curl -ILH "Accept: application/rdf+xml" http://viaf.org/viaf/36978042.rwo

I got a 303 redirect and then a 404. The reason for this seems to be that your web server doesn't support HTTP HEAD requests correctly (GET requests, with curl -iLH, work). This should be fixed, since clients with an own cache often use HTTP HEAD to see if a resource has changed.

Another suggestion about naming the resources: It's a bit a miracle what ".rwo" may denote. In my ears it sounds quite application dependent, and it could be much clearer to use an URI like

http://viaf.org/id/36978042

to designate the person, and a 303 redirect to the actual representation.

Richard raised the question if content negotiation is helpful at all in your situation, because clients normally will not address unimarc or marc21 in HTTP accept headers, so client programmers would probably use self-built URIs anyway. In his page "Frequently observed Problems on the Web of Data" (http://pedantic-web.org/fops.html) he says a lot more about that topic.

One last point: As of now, the XML representation is much richer than the RDF representation. The latter basicly provides links to other representations, but is currently in no way equivalent to them, which could be missleading to clients. But I take your words for that you plan to enrich the RDF representation with all the valuable data you already have in XML - which would be really, really great.

All the best for your work.

Cheers, Joachim