Metadata Schemes

In my last post, I mentioned that there are three types of metadata: descriptive, structural, and administrative. Today, I am going to talk more about metadata schemes.

Many different metadata schemes are being developed in a variety of user environments and disciplines. I will discuss the most common ones in this post.

Dublin Core

The Dublin Core Metadata Element Set arose from discussions at a 1995 workshop sponsored by OCLC and the National Center for Supercomputing Applicatons (NCSA). As the workshop was held in Dublin, Ohio, the element set was named the Dublin core. The continuing development of the Dublin Core and related specifications is managed by the Dublin Core Metadata Initiative (DCMI).

The original objective of the Dublin Core was to define a set of elements that could be used by authors to describe their own Web resources. Faced with a proliferation of electronic resources and the inability of the library profession to catalog all these resources, the goal was to define a few elements and some simple rules that could be applied by noncatalogers. The original 13 core elements were later increased to 15: Title, Creator, Subject, Description, Publisher, Contributor, Date, Type, Format, Identifier, Source, Language, Relation, Coverage, and Rights.

Because of its simplicity, the Dublin Core element set is now used by many outside the library community - researchers, museums, music collectors to name only a few. There are hundreds of projects worldwide that use the Dublin Core either for cataloging or to collect data.

Meanwhile the Dublin Core Metadata Initiative has expanded beyond simply maintaining the Dublin Core Metadata Element Set into an organization that describes itself as "dedicated to promoting the widespread adoption of inter-operable operable metadata standards and developing specialized metadata vocabularies for discovery systems.

The Text Encoding Initiative (TEI)

The Text Encoding Initiative is an international project to develop guidelines for marking up electronic texts such as novels, plays, and poetry, primarily to support research in the humanities.

TEI also specify a header portion, embedded in the resource, that consists of metadata about the work. The TEI header, like the rest of the TEI, is defined as an SGML DTD Document Type Definition) — a set of tags and rules defined in SGML syntax that describes the structure and elements of a document. This SGML mark-up becomes a part of electronic resource itself.

Metadata Encoding and Transmission Standard METS)

The Metadata Encoding and Transmission Standard (METS)was developed to fill the need for a standard data structure for describing complex digital library objects. METS is an XML Schema for creating XML document instances that express the structure of digital library objects, the associated descriptive and administrative metadata, and the names and locations of the files that comprise the digital object.

Next time: architecture for for authoring, producing, and delivering information.