Metadata for Electronic Information Resources

摘要

The rationale for cataloging and indexing of electronic information is much the same as for print materials. Cataloging and indexing provide a surrogate for the item, which facilitates resource discovery and access. But, what has changed in the electronic information environment is the terminology. In the Internet environment, the terms cataloging and indexing have been replaced with the term metadata. Metadata is often defined as data about data or information about information. The term, which originated with the data and computer science communities, is now in general use for the cataloging and indexing of electronic information sources. Metadata serves three general purposes. It supports resource discovery and locates the actual digital resource by inclusion of a digital identifier. As the number of electronic resources grows, metadata is used to create aggregate sites, bringing similar resources together and distinguishing dissimilar resources. There are a variety of metadata schemes that serve different purposes for different object types, subjects and audiences, including the Dublin Core, Metadata Object Description Schema (MODS), the Global Information Locator Service, the Text Encoding Initiative Header, the Encoded Archival Description, the Content Standard for Digital Geospatial Metadata, the Data Documentation Initiative, and the draft Technical Standard for Still Images. A metadata scheme has three components: semantics, content and syntax. An extension adds elements to an existing scheme to describe a particular resource type, handle material on a particular subject, or address the needs of a particular user community. Profiles are subsets of a larger scheme that are implemented by a particular user community. Metadata can be embedded in an electronic resource or stored in a separate file.