The LC Linked Data Service is an initiative of the

Library of Congress The Library of Congress (LOC) is the research library that officially serves the United States Congress and is the ''de facto'' national library of the United States. It is the oldest federal cultural institution in the country. The library ...

that publishes authority data as

linked data In computing, linked data (often capitalized as Linked Data) is structured data which is interlinked with other data so it becomes more useful through semantic queries. It builds upon standard Web technologies such as HTTP, RDF and URIs, but ...

. It is commonly referred to by its URI: id.loc.gov. The first offering of the LC Linked Data Service was the

Library of Congress Subject Headings The Library of Congress Subject Headings (LCSH) comprise a thesaurus (in the information science sense, a controlled vocabulary) of subject headings, maintained by the United States Library of Congress, for use in bibliographic records. LC Subject ...

(LCSH) dataset, which was released in April 2009.

Datasets

(LCSH) * Library of Congress Name Authority File (LCNAF) *

Library of Congress Classification The Library of Congress Classification (LCC) is a system of library classification developed by the Library of Congress in the United States, which can be used for shelving books in a library. LCC is mainly used by large research and academic librar ...

—because LC Classification uses a different

MARC Marc or MARC may refer to: People * Marc (given name), people with the first name * Marc (surname), people with the family name Acronyms * MARC standards, a data format used for library cataloging, * MARC Train, a regional commuter rail system o ...

format than LC Authorities, mapping LC Classification to MADS/RDF was more difficult than mapping LCSH or LCNAF. * Library of Congress Thesaurus for Graphic Materials * Various

codes * Various preservation vocabularies

Formats

The service presents data in MADS/RDF and

SKOS Simple Knowledge Organization System (SKOS) is a W3C recommendation designed for representation of thesauri, classification schemes, taxonomies, subject-heading systems, or any other type of structured controlled vocabulary. SKOS is part of the ...

where appropriate, but also uses its own ontology to describe classification resources and relationships more accurately. All records are available individually via content negotiation as XHTML/RDFa,

RDF/XML RDF/XML is a syntax,RDF/XML Syntax Specification
N-Triples N-Triples is a format for storing and transmitting data. It is a line-based, plain text serialisation format for RDF (Resource Description Framework) graphs, and a subset of the Turtle (Terse RDF Triple Language) format. N-Triples should not be ...

, and JSON. Each vocabulary is also available to download in its entirety. Id.loc.gov does not currently provide a

SPARQL SPARQL (pronounced " sparkle" , a recursive acronym for SPARQL Protocol and RDF Query Language) is an RDF query language—that is, a semantic query language for databases—able to retrieve and manipulate data stored in Resource Description ...

endpoint.

Uses

All of LCSH are crosslinked with (), an authority file from the Bibliothèque nationale de France.

Technical aspects

The id.loc.gov site initially used a fairly lightweight

Python Python may refer to: Snakes * Pythonidae, a family of nonvenomous snakes found in Africa, Asia, and Australia ** ''Python'' (genus), a genus of Pythonidae found in Africa and Asia * Python (mythology), a mythical serpent Computing * Python (pro ...

program to serve linked data.

References

External links