Introduction to Metadata: Pathways to Digital Information
This online publication is the work of the Getty Standards Program of the Getty Research Institute. Several authors contributed to the work which covers such topics as definitions of metadata, metadata and the World Wide Web, metadata mapping and interoperability, and crosswalks of metadata standards. A glossary and a list of acronym definitions are included.

Understanding Metadata
This publication is a "revision and expansion" of an earlier NISO (National Information Standards Organization) report, Metadata Made Simpler: A Guide for Libraries. It presents a general discussion of metadata as it relates to the preservation, discovery, and use of resources in library environments. There are also sections on creating metadata, specific standards, crosswalks, registries, and future trends, as well as a bibliography and glossary.

Institute of Museum & Library Services (IMLS): Framework of Guidance for Building Digital Collections
The IMLS framework paper "is intended as a resource for grant applicants, IMLS and other federal funding agencies, rather than as a set of requirements." Included is a section dealing specifically with metadata which lays out five general principles as well as providing a number of bibliographies.

Digital Libraries: Metadata Resources
This site, sponsored by IFLA (International Federation of Library Associations) offers categorized links to other library-related metadata resources.

Preserving Access to Digital Information (PADI)
PADI is a "subject gateway to digital preservation resources." The site offers pages on metadata in general and preservation metadata in particular. Included on each is a short discussion of the topic followed by extensive annotated bibliographies of related articles, guidelines, projects, etc.

Metadata Principles and Practicalities

Through the use of two specific examples of initiatives, the Dublin Core Metadata Initiative and the IEEE Learning Object Metadata Working Group, the authors discuss in detail the ideas of metadata "principles" and "practicalities." Principles "are those concepts judged to be common to all domains of metadata and which might inform the design of any metadata schema or application." Practicalities, on the other hand, are "the rules of thumb, constraints, and infrastructure issues that emerge from bringing theory into practice in the form of useful and sustainable systems."

Preserving the Whole: A Two-Track Approach to Rescuing Social Science Data and Metadata
As its abstract explains, this paper is "a meticulously detailed case study of migration as a preservation strategy. It explores the options available for migrating both data stored in a technically obsolete format and their associated documentation stored on paper, which may itself be rapidly deteriorating. . . . Moreover, the authors make the important observation that data sets will be indecipherable and cannot survive at all, regardless of the file format in which they are stored, if there is no effort made also to preserve their codebooks. A codebook is essential documentation that relates the numeric data to meaningful fields and values of information."

Metadata Standards & Information Analysis: A Survey of Current Metadata Standards & Underlying Models
As the introduction explains, "This thesis surveys several standards: the Dublin Core Metadata Initiative (DCMI), the Warwick Framework and the Resource Description Framework (RDF), and the Digital Object Identifier (DOI). Although created for different purposes by different groups of people, these standards are closely related. This thesis will describe the standards in detail, and explore the relations between them." The paper also discusses the Functional Requirements for Bibliographic Records (FRBR) and the INDECS metadata model.

MetaMap
MetaMap is maintained by the staff of the University of Montreal's School of Library and Information Sciences. It offers links to information on over 180 metadata initiatives through a graphical interface in the form of a subway map. Topics are represented by subway lines and include Creation, Organisation, Dissemination, Preservation, Archives, Moving Images, and Text.

Centre for Economic and Social Studies on the Environment (CESSE): Metadata Standards Directory
These pages provide visitors with an annotated list of lists dealing with metadata standards, as well as direct links to metadata standard sites.

The Meta-Data and Data Management Information Page
Hosted by the IEEE (Institute of Electrical and Electronics Engineers), this site offers information organized into a number of categories: conferences and projects, working groups, archives of the IEEE metadata listserv, bibliography, and other efforts. The last section offers links to standardization projects, journals, tools, and general metadata projects.

Metacrap: Putting the Torch to the Straw-Men of Meta-Utopia
Author Cory Doctorow offers a short, tongue-in-cheek discussion of metadata, what it is, and the pitfalls of its use.

Dublin Core Metadata Element Set (ANSI/NISO Z39.85-2001)
The Dublin Core Metadata Element Set (DCMES) became an official ANSI/NISO standard in 2001. The fifteen-element metadata standard is the product of a series of a number of workshops which began in 1995 and is designed to facilitate resource discovery. Intended to serve international users in a flexible manner, the elements are all optional, repeatable, and labeled with descriptive names. Metadata generated from this scheme may be represented in a number of ways (e.g., HTML, RDF) for use on the Internet.

Minnesota Recordkeeping Metadata Standard (Minnesota Office of Technology Standard IRM 20)
The Minnesota Recordkeeping Metadata Standard was developed to facilitate records management by government entities at any level of government. It is based directly on the standard authored by the National Archives of Australia, but has been adapted to meet the Minnesota government environment. The standard is comprised of twenty metadata elements, ten of which are mandatory.

Recordkeeping Metadata Standard for Commonwealth Agencies (Australia)
Released in early 1999, this metadata standard directly addresses recordkeeping requirements through twenty metadata elements, eight of which are mandatory. The standard is intended for use with purely electronic recordkeeping systems as well as those that are hybrid (electronic, paper, and other formats). Many of the standard's metadata elements have counterparts in the Dublin Core Metadata Element Set. The standard is part of a government-wide comprehensive records management scheme that includes a government information locator service.

New South Wales Recordkeeping Metadata Standard
This recordkeeping metadata standard aims, among other things, to enhance effective records management and to support the interchange of records between different organizations and different systems. It is based, in large part, on the National Archives of Australia's Recordkeeping Metadata Standard for Commonwealth Agencies, and is intended to complement two other State Records publications: Standard on Recordkeeping in the Electronic Business Environment and the Manual for Designing and Implementing Recordkeeping Systems.

PROS 99/007 Standard for the Management of Electronic Records, Specification 2: VERS Metadata Scheme (Public Record Office Victoria)
The VERS metadata scheme is an adaptation of the National Archives of Australia's Recordkeeping Metadata Standard for Commonwealth Agencies, but the implementation strategy and goals differ significantly. For example, the VERS scheme advocates the encapsulation of objects at or near the time of their creation using eXtensible Markup Language (XML) such that they are self-documenting.

e-Government Metadata Standard (UK Office of the e-Envoy)

This standard is intended for use by UK government officers "when creating metadata for their information resources or designing search systems for information systems." It features twenty-one metadata elements intended to facilitate information and records management, including Accessibility, Audience, Disposal, Location, Preservation, and Status.

Metadata Encoding Transmission Standard (METS)
The METS standard, developed by the Digital Library Federation and maintained by the Library of Congress, aims at providing "an XML document format for encoding metadata necessary for both management of digital library objects within a repository and exchange of such objects between repositories (or between repositories and their users)." METS documents consist of four primary parts: descriptive metadata, administrative metadata, file groups, and a structural map.

Library of Congress Digital Repository Development: Core Metadata Elements
This list of metadata elements, drawn from other projects, is used to describe objects in digital repositories at the Library of Congress. Metadata elements are categorized as to administrative, descriptive, and structural and may be applied in a hierarchy fashion at various levels of collection.

Metadata Object Description Schema (MODS)
MODS is a project by the Library of Congress' Network Development and MARC Standards Office. The standard, which is still under development, is intended to complement other metadata schemes, including the MARC (Machine Readable Cataloging) and METS (Metadata Encoding Transmission Standard) formats. It is expressed as an eXtensible Markup Language (XML) schema.

Data Dictionary - Tech Metadata for Digital Still Images (Draft Standard, NISO Z39.87-2002; AIIM 20-2002)
The stated purpose of this draft standard is to "define a standard set of metadata elements for digital images. Standardizing the information allows users to develop, exchange, and interpret digital image files. The dictionary has been designed to facilitate interoperability between systems, services, and software as well as to support the long-term management and continuing access to digital image collections." The NISO committee, in conjunction with others including the Library of Congress, is also developing an eXtensible Markup Language (XML) schema for use with the standard (draft entitled "NISO Metadata for Images in XML" or MIX).

Open Archives Initiative Protocol for Metadata Harvesting (OAI-PMH)
The OAI is supported by the Digital Library Federation, the Coalition for Networked Information, and the National Science Foundation. Its goal is to develop and promote "interoperability standards that aim to facilitate the efficient dissemination of content." The OAI-PMH "defines a mechanism for harvesting XML-formatted metadata from repositories. The protocol does not provide a mechanism for harvesting data (content) that is not encoded in XML. The protocol also does not mandate the means of association between that metadata and related content. Since many clients may want to access the content associated with harvested metadata, data providers may deem it appropriate to define a link in the metadata to the content. The mandatory Dublin Core format provides the identifier element that can be used for this purpose."

Reference Model for an Open Archival Information System (NASA, Consultative Committee for Space Data Systems (CCSDS), ISO/DIS 14721.2)
Although still in draft form, the OAIS reference model serves as a foundation for much other work in the areas of long-term digital preservation and access. An OAIS is defined as "an archive, consisting of an organization of people and systems, that has accepted the responsibility to preserve information and make it available for a designated community." As the draft explains, "The reference model address a full range of archival preservation functions including ingest, archival storage, data management, access, and dissemination. It also address the migration of digital information to new media and forms, the data models used to represent the information, the role of software in information preservation and the exchange of digital information among archives. It identifies both internal and external interfaces to the archive functions, and it identifies a number of high-level services at these interfaces. It provides various illustrative examples and some 'best practice' recommendations. Finally, it attempts to define a maximal archive to provide a broad set of useful terms and concepts, but it defines a minimal set of responsibilities for an archive to be called an OAIS." The OAIS reference model is under consideration as an ISO standard (ISO/DIS 14721.2). For more general information, visit the "Open Archival Information System (OAIS) Resources" page hosted by the RLG (http://www.rlg.org/longterm/oais.html).

W3C (World Wide Web Consortium): The Semantic Web / Resource Description Framework (RDF)
RDF is a framework for describing and interchanging metadata on the Web through the use of eXtensible Markup Language (XML). The W3C web site offers access to the specifications, technical reports, related articles, developer resources, and links to implementation projects.

Western States Dublic Core Metadata Best Practices (WSDCMBP)

The WSDCMBP is an extension and application of the basic Dublin Core metadata element set. It was developed and is maintained in conjuction with the Colorado Digitization Program, which aims to bring together digital resources from various cultural institutions in the state.

Preservation Metadata for Digital Collections: Exposure Draft
This proposed metadata standard, developed by the National Library of Australia, is comprised of twenty-five metadata elements and a number of sub-elements concerned only with preservation. The authors point out that the set is "intended to be a statement of the information we believe is needed to manage preservation of digital collections. It is meant to be a data output model, not a data input model. It indicates the information we want out of a metadata system, not necessarily what data should be entered, how it should be entered, by whom and at what time; nor does it concern itself with how the metadata should be associated with what it is describing. We believe this model should be applicable to many implementations that may decide to record this information in a variety of ways. This model simply says: 'however you do it, this is what you have to deliver so we can manage preservation.'"

Machine Readable Cataloging (MARC 21)

MARC 21, maintained by the Library of Congress, allows bibliographic and related information to be represented, managed, and communicated in machine-readable, or digital, form.

Global Information Locator Service (GILS)
This is the home page of the U.S. Federal GILS project, which is based upon the international information search standard ISO 10163 (ANSI Z39.50). The site offers general information about the project, as well as links to other federal, state, and international GILS ventures.

AGLS (Australian Government Locator Service)
This is the official site for the Australian Government Locator Service maintained by the National Archives of Australia. The AGLS metadata standard, which is based upon the Dublin Core scheme, consists of nineteen elements. The goal of the project is to increase the visibility and accessibility of government services and information on the Internet. A users manual is offered in both PDF and HTML formats. Additionally, the NAA plans on developing an interactive thesaurus to facilitate user-friendly, natural-language searching. Other links lead visitors to additional information about metadata research and the evolution of AGLS.