Friday 1 May 2009

LCSH as Linked Data ... officially!

Yesterday was, in my estimation, pretty historic. The Library of Congress officially launched the LC Authorities and Vocabularies service. You might recall a previous post relating to lcsh.info in which I lamented the LC's decision to pull down a SKOS demonstrator of LCSH, explicitly designed to explore the possibilities of Linked Data and dereferenceable URIs. All the background is in the previous post; but the whole episode appears to have been a PR disaster for LC.

The great news is that the LC Authorities and Vocabularies service (let's call it LCAV henceforth, shall we?) officially re-launched lcsh.info in a bigger, better and much improved form. The service essentially enables both humans and machines to access a plethora of LC authority data. Like lcsh.info, the service employs Semantic Web approaches to exposing this data and implements approaches to Linked Data by exposing and linking data on the Web via dereferenceable URIs.

Five minutes exploring the website reveals that LCAV serves up the entire LCSH for free, with incredible search and browse functionality, leaving Connexion in the shade. The concept URIs point to detailed data modelled in SKOS as RDFa for human readability, but with links to SKOS as RDF/XML, N-Triples and (the less familiar?) JSON for machine processing. RDF graphs can even be visualised by clicking, well, the 'visualize' tab – incredible. Mappings to other vocabularies are also provided.
On top of all this, LCSH can be downloaded in its entirety as RDF/XML or N-Triples (SKOS)! LCAV also indicate that further authority data will be made available soon.

Make no bones about it, this is historic stuff, not only because the service is so good but because this terminological data is no longer locked down. I think it's important to stroke our imaginary beards over the significance of the LC's change of direction. Is this the beginning of the end for locked down terminological data?! Will they be like dominoes henceforth? A fiver says DDC does the same by the end of the year. Any takers???

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