Linked Data

Linked Data is a set of best practices for publishing and connecting structured data on the web. It is about making data on the web machine-readable and providing connections and links to other data sets.

In the library community, much of the data is stored in proprietary databases (ILS's, digital repositories, etc), and web search engines cannot index this data. This means that users cannot discover much library content on the web. Studies have shown that most people begin their search on the web, not by visiting a library webpage or catalog (See OCLC's Perceptions of Libraries, 2010: Context and Community  report to the membership).

The library community has made great strides in recent years in recognizing and finding solutions to this issue. Some of the latest projects include the Library of Congress-led BIBFRAME initiative to replace the MARC format using linked data technologies, OCLC linked data research projects, and the Linked Data for Libraries (LD4L) collaborative, to name just a few.

This page includes links to introductory resources, linked data communities, datasets, and examples of library catalogs and other applications using linked data.

Introductory Resources

  • W3C Linked Data
    Find out more about what linked data is, what it is used for, examples of linked data, and the current status of various linked data specifications (RDF, RDFa, etc.) and groups.
  • Linked Data for Libraries
    Created by OCLC, this 15-minute YouTube video introduces the concepts and technology behind linked data, including the benefits it brings to libraries.
  • Linked Open Data - What is it?
    Created by Europeana, a 3 minute animation that explains what linked open data is and why it’s a good thing for users and data providers.
  • Tim Berners-Lee on the Next Web
    Watch the TED talk by Tim Berners-Lee (inventor of the World Wide Web) from 2009, which kicked off the "raw data now" movement.

Publications

Linked Data Communities

  • ALA Linked Data Interest Group
    A forum for discussion of issues related to linked library data and the role of library metadata in the semantic web. This is a joint interest group (ALCTS/LITA) of the American Library Association.
  • Linked Open Data in Libraries Archives and Museums (LODLAM)
    LODLAM.net is an informal, borderless network of enthusiasts, technicians, professionals and any number of other people who are interested in or working with Linked Open Data pertaining to galleries, libraries, archives, and museums.
  • Linked Data for Libraries (LD4L)
    Begun in 2014 and funded by the Andrew W. Mellon Foundation, LD4L was a collaboration between Cornell University Library, the Harvard Innovation Lab, and the Stanford University Libraries. It has since expanded and morphed into additional collaborations.

Datasets

  • Library of Congress Linked Data Service
    Interactive and machine access to Library of Congress ontologies, controlled vocabularies, and other lists for bibliographic description.
  • The Linked Open Data Cloud
    An interactive graph view of thousands of datasets that have been published in a linked data format.
  • Virtual International Authority File (VIAF)
    VIAF is hosted by OCLC, and a joint project of several national libraries.
  • Wikidata
    A knowledge base of structured data that can be read and edited by both humans and machines.
  • WorldCat Works
    OCLC made millions of bibliographic work descriptions available as linked data. Works are high level descriptions of resources containing information such as author, name, descriptions, and subjects, etc. common to all editions of a work.

Publishing and Consuming Linked Data

These are all organizations that have either published their data as linked data, or are consuming it to enhance local discovery of their library catalog resources or other repositories.

  • The British National Bibliography as Linked Open Data
    This is a subset of the full British National Bibliography and currently includes published books (including monographs published over time) and serial publications, representing approximately 4.4 million records.
  • Evergreen and Koha ILS
    Record details are expressed in the schema.org vocabulary using RDFa.
  • Linked Data for Production (LD4P2): Discovery Group
    The LD4P2 Discovery Working Group is looking at enhancing discovery of library resources by consuming external data. Find examples of enhanced discovery features powered by linked data at several organizations.
  • National Library of France
    Online since June 2011, the data.bnf.fr project endeavours to make the data produced by Bibliothèque nationale de France (French National Library) more useful on the web. 
  • National Library of Spain
    The National LIbrary of Spain published the full catalog as RDF.
  • Open Library
    An Internet Archive initiative, Open Library is an open, editable library catalog, building towards a webpage for every book ever published.
  • WorldCat.org
    Since June 2012, OCLC has been adding Schema.org descriptive mark-up to WordCat.org pages, making it the largest set of linked bibliographic data on the web.