February 2, 2001
(A division of the American Library Association)
Cataloging and Classification Section
Committee on Cataloging: Description and Access
The charges to the Task Force on the VRA Core and a summary of actions:
Evaluating the relationship between library metadata (AACR2, USMARC) and the Visual Resources Association/Data Standards Committee Core Categories for describing visual resources collections to determine how well the VRA Core Categories map into AACR2 and MARC.
TF Action: The VRA Data Standards Committee has mapped the Core Categories to MARC as well as to other metadata standards. A section of this report further reviews the mapping to MARC and AACR, category by category.
Identifying the issues surrounding the use of VRA metadata in AACR2 cataloging records. The Task Force shall refer to the four user tasks set forth in the IFLA Functional Requirements for Bibliographic Records and the Computer File Core Record Requirements established by PCC in evaluating the VRA metadata standard.
TF Action: A section of the report analyzes the “user tasks” identified in FRBR as they relate to the VRA Core Categories. The Task Force report does not include comparisons to the PCC Core Record Requirements for Computer Files, or to the PCC Core Record Requirements for Graphic Materials. [The latter comparison was suggested as an addition to the charge in June, 1999. ]
Assessing the consequences and impact of integrating records containing the VRA core categories into library databases, evaluating mechanisms for integration and recommending appropriate measures for libraries.
TF Action: We focus on general issues of record compatibility rather than record integration. Sections of the report address theoretical issues involving library data structures and the VRA Core Categories.
Preparing rule revision proposals and discussion papers as needed.
TF Action: None. The TF feels that the VRA Core is chiefly a data structure standard. Recommendations for changes to library standards would most likely be directed to the MARC Advisory Committee.
Monitoring of projects and activities that use VRA.
TF Action: None. According to one TF member, the VRA Core is used by a number of libraries but mostly as inspiration. We are aware of the IRIS project in New England (using Core 2.0) and the Harvard VIA project (data structure mapped to Core 2.0). There had been some early discussion of providing a VRA Core view in CORC, but that did not happen.
Informing others of library perspectives through a designated liaison to VRA and informing CC:DA about the development of VRA.
TF Action: As a member of the TF and the VRA Data Standards Committee liaison to the the MARC Advisory Committee, Sherman Clarke is a de facto liaison between CC:DA and VRA Data Standards Committee (DSC). At his request, this report will be sent to DSC members prior to the VRA Conference scheduled for the end of February, 2001. The TF has no plans to request that a designated liaison be appointed. The overlap between metadata communities is sufficient to ensure meaningful exchange of information.
The Task Force shall prepare a summary of the VRA metadata standard which shall include the following information
some background on history and community served
description of metadata element set
sample records if possible
citations for more information, implementation projects, etc. Include Web sites.
TF Action: Appendixes to this report provide some background, Core category descriptions, sample records and a brief bibliography.
In the United States, the oldest, richest and most enduring metadata standards are those used in the creation of catalog records located in library catalogs. These are AACR and MARC and are best suited for the description of books or other physical resources traditionally housed in library collections. The advent of networks and the Internet gives rise to enormous potential for record sharing that goes well beyond libraries and catalogers, and well beyond descriptions of traditional library resources. With that potential comes the hope that in a single view, a researcher can find relevant materials through the use of databases of resource descriptions that include more than library catalogs.
For the last several years, librarians have pondered how to achieve a virtual union catalog for records from disparate databases that are based on widely differing standards for element definition and content. In addition to AACR/MARC the resource description records could be based on Dublin Core, TEI headers, CIDOC information categories or the Core Categories for Visual Resources (VRA), among others. The library community, especially catalogers, also saw the desirability of sharing content, of using supplied metadata from other sources and vice versa. The ideal would be to create metadata records that could be used and re-used, rather than creating and maintaining multiple parallel records for a single resource or to represent different functions involving that resource.
To generate a unified view that would result in meaningful discovery and retrieval and to support record sharing, semantic and content “interoperability” is needed. This can be achieved in one of two ways: transporting records to a single, shared database; or, using a single search interface to multiple databases. Either will require mapping or crosswalks that identify fields/tags/labels in each metadata set that correspond closely (if not perfectly) to each other. This semantic mapping is the first essential step in achieving interoperability. A second essential step is to agree on rules governing content, or to agree on mechanisms for resolution. Such rules would apply to the use of controlled vocabularies, name and subject, and to formulation of information that falls outside controlled vocabularies.
Early on, CC:DA began a study of newly emerging metadata standards with the intent of determining the potential for integrating records based on non-library metadata standards with library databases. More recently, CC:DA has shifted its focus of study from the centrality of the library catalog as a tool for resource discovery to the recognition that the library catalog will be one among many tools. From the beginning these studies have occasionally been handicapped by a lack of common terminology and understanding of the various types and uses of metadata. We sometimes found ourselves trying to compare apples to oranges. To avoid confusion and to forge a common understanding for the remainder of this report, the following metadata terms and their descriptions are offered:
data content: governed by standards that provide rules for populating tagged or labeled fields (set of statements that collectively describe a resource). These standards include AACR, ISBD=s, DCRB (Descriptive Cataloging of Rare Books), AMIM (Archival Moving Image Materials), and to a slight extent, MARC21.
: governed by standards that include a defined set of element labels or tag/field names and application rules (semantics; data dictionaries). These include Dublin Core, CDWA (Categories for the Description of Works of Art); VRA Core
; and to some extent, MARC21.
: governed by standards that provide rules for encoding records for transfer from different sources (syntax). These include MARC21, UNIMARC, SGML, XML.
This report continues the CC:DA study of metadata standards by looking at the VRA Core Categories (VRA) and assessing the potential for interoperability with library databases. It is important to keep in mind that the VRA Core is a data structure standard. Control of the data content or values for each element is based on recommendation and suggestion rather than rule. In principle, any comparison of the VRA Core can only be to other, comparable standards such as the Dublin Core, MARC (in part), or the CIDOC Information Categories. In fact, recommended practice for data values is worded strongly enough in the VRA Core to suggest that some assessment of these is possible for compatibility with other data content standards. Sections of this report will consider both by looking at the VRA Core in terms of its success in meeting requirements described in the Functional Requirements for Bibliographic Records (FRBR), evaluating the relationship to library metadata standards (AACR and MARC) and comparison to another metadata data structure standard (Dublin Core Metadata Element Set).
VRA Core categories compared to AACR and to MARC