Library of Congress
LC
The world's largest library, serving as the research arm of the United States Congress and de facto national library.
The Library of Congress is the research library of the United States Congress and the de facto national library of the United States. As the world's largest library, it plays a central role in developing and maintaining metadata standards for libraries, archives, and digital collections. LC is responsible for widely adopted standards including MARC, MODS, METS, EAD, and the Library of Congress Subject Headings (LCSH), which underpin cataloging and resource discovery worldwide.
Standards (24)
Analyzed Layout and Text Object
(ALTO)Encodes the physical layout and recognized text of digitized document pages from OCR output.
AudioMD: Audio Technical Metadata Extension Schema
(AudioMD)An XML schema for recording technical metadata about audio digital objects in preservation systems.
BagIt File Packaging Format
(BagIt)A file packaging convention using manifests and checksums for reliable digital content transfer.
BIBFRAME (Bibliographic Framework Initiative)
(BIBFRAME)A linked data vocabulary built around Work, Instance, and Item to replace MARC for library data.
Contextual Query Language
(CQL)A human-readable query language for information retrieval systems, used with SRU and library search protocols.
Encoded Archival Description
(EAD)The XML standard for encoding hierarchical archival finding aids and publishing them on the web.
Extended Date/Time Format
(EDTF)A syntax for expressing dates with uncertainty, approximation, and ranges beyond ISO 8601.
ISO 20775 Holdings Schema
(ISO 20775)An XML schema for expressing library holdings information in a standardized, interoperable format.
ISO 639 Language Codes
(ISO 639)The international standard for language identification codes used across libraries and information systems.
Library of Congress Classification
(LCC)Organizes knowledge into 21 lettered classes designed for large academic and research libraries.
Library of Congress Name Authority File
(LCNAF)Over eight million authority records for the names of persons, organizations, and titles.
Library of Congress Subject Headings
(LCSH)The world's largest general-purpose subject heading system, maintained continuously since 1898.
MARC 21
(MARC 21)The dominant machine-readable format for exchanging bibliographic and authority data in libraries.
MARCXML: MARC 21 XML Schema
(MARCXML)A lossless XML representation of MARC 21 records for use in web and XML environments.
Metadata Authority Description Schema
(MADS)An XML and RDF schema for authority records describing people, organizations, and subjects.
Metadata Encoding and Transmission Standard
(METS)An XML container for packaging structural, descriptive, and administrative metadata for digital objects.
Metadata Object Description Schema
(MODS)A readable XML alternative to MARC 21 for bibliographic description in digital libraries.
NISO Metadata for Images in XML
(MIX)An XML schema for recording technical metadata about digital still images in preservation workflows.
Preservation Metadata: Implementation Strategies
(PREMIS)Records the metadata essential for ensuring digital objects remain usable and authentic over the long term.
Search/Retrieve via URL
(SRU)A web-service protocol for searching databases and retrieving records using HTTP and standard query syntax.
TextMD: Technical Metadata for Text
(TextMD)An XML schema for recording technical metadata about text-based digital objects in preservation systems.
Thesaurus for Graphic Materials
(TGM)A controlled vocabulary for indexing photographs, prints, and other pictorial materials by subject.
VideoMD: Video Technical Metadata Extension Schema
(VideoMD)An XML schema for recording technical metadata about video digital objects in preservation systems.
Z39.50 Information Retrieval Protocol
(Z39.50)A client-server protocol enabling standardized search and retrieval across remote library databases.
