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Library of Congress Subject Headings as SKOS Linked Data

From: Ed Summers <ehs@pobox.com>
Date: Mon, 9 Jun 2008 09:54:06 -0400
Message-ID: <f032cc060806090654u2a5058b9q1daccd9b94644039@mail.gmail.com>
To: "SWD Working SWD" <public-swd-wg@w3.org>, public-lod@w3.org

I'd like to announce an experimental linked-data, SKOS representation
of the Library of Congress Subject Headings (LCSH) [1] ... and also
ask for some help.

The Library of Congress has been participating in the W3C Semantic Web
Deployment Working Group, and has converted LCSH from the MARC21 data
format [2] to SKOS. LCSH is a controlled vocabulary used to index
materials that have been added to the collections at the Library of
Congress. It has been in active development since 1898, and was first
published in 1914 so that other libraries and bibliographic utilities
could use and adapt it. The lcsh.info service makes 266,857 subject
headings available as SKOS concepts, which amounts to 2,441,494
triples that are separately downloadable [3] (since there isn't a
SPARQL endpoint just yet).

At the last SWDWG telecon some questions came up about the way
concepts are identified, and made available via HTTP. Since we're
hoping lcsh.info can serve as an implementation of SKOS for the W3C
recommendation process we want to make sure we do this right. So I was
hoping interested members of the linked-data and SKOS communities
could take a look and make sure the implementation looks correct.

Each concept is identified with a URI like:


When responding to requests for concept URIs, the server content
negotiates to determine which representation of the concept to return:

  - application/xhtml+xml
  - application/json
  - text/n3
  - application/rdf+xml

This is basically the pattern that Cool URIs for the Semantic Web
discusses as the Hash URI with Content Negotiation [4]. An additional
point that is worth mentioning is that the XHTML representation
includes RDFa, that also describes the concept.

At the moment the LCSH/SKOS data is only linked to itself, through
assertions that involve skos:broader, skos:narrower, and skos:related.
But the hope is that minting URIs for LCSH will allow it to be mapped
and/or linked to concepts in other vocabularies: dbpedia, geonames,

Any feedback, criticisms, ideas are welcome either on either the
public-lod [5] or public-swd-wg [6] discussion lists.

Thanks for reading this far!

[1] http://lcsh.info
[2] http://www.loc.gov/marc/
[3] http://lcsh.info/static/lcsh.nt
[4] http://www.w3.org/TR/cooluris/#hashuri
[5] http://lists.w3.org/Archives/Public/public-lod/
[6] http://lists.w3.org/Archives/Public/public-swd-wg/
Received on Monday, 9 June 2008 13:54:41 UTC

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