Library of Congress Classification as linked data

In 2009 and in 2011, the Library of Congress made two of its largestauthority files –Subject Headings and Names available as linked data via LC’slinked data service, id.loc.gov. Both are offered in MADS/RDF and SKOS. It isLC’s objective, in 2012, to publish another of its largest authority files as linkeddata: LC Classification. However, whereas the source records for Subject Headingsand Names are encoded in the MARC Authority format, from which there is arelatively straightforward mapping to MADS/RDF and SKOS, LC Classificationrecords rely on the MARC Classification format. Mapping from LC Classificationto MADS/RDF or SKOS has been a little more challenging. For example, recordsthat represent classification ranges, which are not Concepts intended to be assigned,are not easily accommodated in SKOS. This presents additional problems whenneeding to accurately represent the relationships in RDF for LC Classification. Withcomparison to the publication of LCSH and Names at id.loc.gov, this paper willexamine issues encountered – and how those challenges were addressed – during theconversion of LC Classification to MADS/RDF and SKOS for release as linked dataat id.loc.gov.