Metadata Standards
A range of metadata standards have been developed by the repository and archives community that can guide those wishing to establish a schema. Wherever possible, schemas should be open and comply with widely recognised standards to facilitate interoperability and broader reuse of stored resources. The most commonly used standard, and the one required for interoperability and harvesting via the OAI-PMH, is Dublin Core.
Dublin Core
The Dublin Core standard arose from a 1995 workshop held in Dublin, Ohio. Although there are now a larger number of metadata terms defined by the Dublin Core Metadata Initiative (DCMI), the Simple Dublin Core involves the 15 elements given below. Each is optional and repeatable, and may appear in any order the creator of the metadata wishes.
- Title
- Creator
- Subject
- Description
- Publisher
- Contributor
- Date
- Type
- Format
- Identifier
- Source
- Language
- Relation
- Coverage
- Rights
Simple Dublin Core is widely used, simple and easily adopted. It is built into most repository software.
DCMI has, however, now developed an Abstract Model to support the development of Application Profiles and allow richer use of metadata. As such Simple Dublin Core is now regarded as a legacy use of the standard. These 15 elements have been reincarnated as part of the DCMI Metadata Terms. DCMI Metadata Terms is built around this element set but supports other terms which add further levels of detail to metadata; for example to distinguish between additional or translated titles, or define different types of dates or contributors. Many of the additional DCMI Metadata Terms refine the 15 simple elements.
Other Metadata Standards
Other metadata standards are available for fulfilling more complex purposes, for example for collecting preservation metadata. These standards include
MODS
MODS (Metadata Object Description Schema) as an XML schema is 'intended to be able to carry selected data from existing MARC 21 records, as well as to enable the creation of original resource description records'. This schema includes elements of MARC fields and uses language tags, rather than numeric ones.
PREMIS
PREMIS is an XML schema which supports implementation of version 2.0 of the PREMIS Data Dictionary
IEEE LOM
Institute of Electrical and Electronics Engineers Standards Association (IEEE) 1484.12.1 - 2002 Standard for Learning Object Metadata 'is a data model, usually encoded in XML, used to describe a learning object and similar digital resources used to support learning.' It is often used in the context of online learning management systems (LMS) but is also used by some repositories that hold learning materials.
Some metadata standards are designed to describe aggregations of objects.
METS
METS (Metadata Encoding & Transmission Standard) is maintained by the Network Development and MARC Standards Office of the Library of Congress.
DIDL
The Digital Item Declaration Language (DIDL) is a metadata markup standard developed for the accurate description of mutlimedia objects. It was developed by the Moving Picture Experts Group (MPEG) as an ISO standard.
IMS CP
IMS Global Learning consortium - Content Packaging Specification 'provides the functionality to describe and package learning materials, such as an individual course or a collection of courses, into interoperable, distributable packages. Content Packaging addresses the description, structure, and location of online learning materials and the definition of some particular content types.'
