Evolving MARC 21 for the future Rebecca Guenther CCS Forum, ALA Annual July 10, 2009
Overview of presentation The current MARC environment Successes of MARC Moving to XML RDA and FRBR experimentation Linked data Issues to resolve
Credits Sally McCallum for some slide content John Espley for FRBR implementation Clay Redding for Linked Data content
What is MARC 21? A syntax defined by an international standard for communications with 2 expressions: Classic MARC (MARC 2709) MARCXML A data element set defined by content designation and semantics Institutions do not store “ MARC 21 ”, as it is a communications format Many data elements are defined by external content rules; a common misperception is that it is tied to AACR2 A set of 5 formats for different purposes: Bibliographic, Authority, Holdings, Classification, Community Information
The current MARC environment Billions of rich descriptive records in MARC systems Many national formats have been harmonized with MARC 21 Integrated library systems that support MARC bibliographic, authority and holdings format for different functions Wide sharing of records for 30+ years OCLC is a major source of records MARC records are being reused (sometimes converted) and repackaged
MARC successes Can carry data formulated by different cataloging rules and conventions Multiple descriptive rules, different principles and models Different subject thesauri Multiple languages and scripts Cooperation in record exchange has resulted in widespread use and cost savings Richness of MARC records supports multifaceted retrieval Coded data Parsed data
Problems with MARC MARC 2709 syntax problems Limitation of available fields, subfields, indicator values, etc. Redundant data (fixed vs. variable fields) Controlled values embedded in the standard Ability to link Limits to extensibility Lack of explicit hierarchical levels
Some progress … MARCXML Definition of $u, $w and $0 for linking Definition of $2 to specify source of controlled values Exploration into use of URIs MODS
Streamlining MARC 21 into the future Take advantage of XML Increasingly use MARC 21 in an XML structure Take advantage of freely available XML tools Develop simpler (but compatible) alternatives MODS Allow for interoperability with different XML metadata schemas Assemble coordinated set of tools Provide continuity with current data Provide flexible transition options
MARCXML MARCXML uses the MARC data element set in an XML syntax Lossless roundtrip conversions Simple flexible XML schema, no need to change when MARC 21 changes Interoperability with different XML schemes by taking advantage of free XML tools Collaborative use of metadata for access (e.g.OAI) Continuity with current data and flexible transition options Example:
MARC 21 evolution to XML
More use of MARCXML Transition to exchange in MARCXML instead of MARC 2709 Take advantage of namespaces to allow for extensions (e.g. technical metadata) Potential to extend with new attributes or subfield markers
Other related XML schemas: MODS Eliminates some of the problems with MARC (e.g. lack of tags/subfield codes) More user-friendly (uses language tags) Repackages redundant data elements into one Can carry hierarchical data Less tied to cataloging rules Highly compatible with MARC but simpler, although retaining some richness Widely implemented especially for digital projects Governed by Editorial Committee Example:
Other related XML schemas: METS METS A container/information package Wrapper for MARCXML and MODS descriptions Allows for additional technical and preservation metadata Enables tracking of actions on the metadata itself LC is exploring a native XML database for search and retrieval bringing together records from many internal systems using MODS/MARCXML/METS
Experimentation with RDA, FRBR and RDF MARC changes to accommodate RDA MODS changes to accommodate RDA FRBR experimentation VTLS has implemented a FRBR based system using MARC Other systems are looking at migrating to reflect entity- relationship models Semantic web experiments Modeling MODS and MADS as RDF Modeling MARC as RDF See Martha Yee ’ s article in Information Technoclogy and Libraries (v. 28, no. 2, June 2009)
Example of FRBR implementation of MARC: VTLS Single database can have FRBR and non-FRBR records System is “aware” of FRBR record level and changes displays as needed Display of FRBR records are in tree structure Local level fields have values of W, E, and M to indicate type of FRBR record 001 and 004 used as linking tags
Experimentation with “ Linked data ” Library of Congress Authorities & Vocabularies service: Allows both human-oriented and programmatic access to LC-promulgated authorities and vocabularies Actionable URIs associated with concepts First offering is Library of Congress Subject Headings, but more to come: e.g. Thesaurus of Graphic Materials, ISO 639-2, MARC code lists, etc Advantages Facilitate development and maintenance process for vocabularies Expose vocabularies to wider communities Offer bulk downloads Example:
Issues to resolve for bibliographic formats Actionable vs. descriptive Parsed vs. text Controlled/access vs. transcribed Codes vs. words Library vs. non-library traditions My model vs. your model Stability vs. change Basic retrieval vs. scholar retrieval Cost of change
How do we move forward? Continue RDA/FRBR implementation changes Transition to XML for exchange (syntax) Evolve MARC 21 (data element set) Analyze successes that need to be carried over into a streamlined MARC Consider MODS features to be incorporated Consider use of MARC 21 for different cataloging rules, models and traditions, not just RDA Consider cost implications Assure continuity with current data Evolution will take some time and will be in phases
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