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DCMI Qualifiers

Creators: Dublin Core Usage Committee
Date Issued: 2000-07-11
This Version: http://dublincore.org/specifications/dublin-core/dcmes-qualifiers/
Latest Version: http://www.dublincore.org/specifications/dublin-core/dcmes-qualifiers/
Replaces:
  • http://www.dublincore.org/specifications/dublin-core/dcmes-qualifiers/2000-07-11/
  • Status: recommendation
    Description: This document describes the principles governing Dublin Core qualifiers, the two categories of qualifiers, and lists instances of qualifiers approved by the Dublin Core Usage Committee.

    Introduction

    This document presents the results of a process to develop exemplary qualifiers for the Dublin Core Metadata Element Set ( DCMES). The qualifiers listed here were identified in element-specific working groups of the Dublin Core Metadata Initiative ( DCMI) and judged by the DCMI Usage Committee to be in conformance with principles of good practice for the qualification of Dublin Core metadata elements. Working groups proposed candidate qualifiers judged likely to be of widespread use (and hence to increase the likelihood of interoperability among applications) and these proposals were subsequently debated and balloted by the DCMI Usage Committee.

    In determining the makeup of these qualifiers, preference was given to vocabularies, notations, and terms already maintained by established agencies. It should be emphasized that the list of externally-maintained vocabularies identified here is a preliminary list. There are many more controlled vocabularies or classification systems that are not identified here. The DCMI welcomes suggestions concerning additional existing standards that might serve as qualifiers.

    Inevitably, there will be situations where an agent or client will encounter DCMES descriptions that use unfamiliar qualifiers developed by implementors for specialized local or domain-specific needs. The useful interpretation of such a DCMES description will depend on the ability of an application to ignore the unknown qualifiers and fall back on the broader meaning of the element in its unqualified form. The guiding principle for the qualification of Dublin Core elements, colloquially known as the Dumb-Down Principle, is that a client should be able to ignore any qualifier and use the description as if it were unqualified. While this may result in some loss of specificity, the remaining element value (without the qualifier) should continue to be generally correct and useful for discovery.

    It is expected that implementors will develop additional qualifiers for use within local applications or specific domains. Such qualifiers may not be understood by other applications. However, qualifiers that conform to the principles of qualification defined here are more likely to be reusable by other communities within the broader context of cross-domain discovery.

    At the time of the ratification of this document, the DCMI recognizes two broad classes of qualifiers:

    • Element Refinement. These qualifiers make the meaning of an element narrower or more specific. A refined element shares the meaning of the unqualified element, but with a more restricted scope. A client that does not understand a specific element refinement term should be able to ignore the qualifier and treat the metadata value as if it were an unqualified (broader) element. The definitions of element refinement terms for qualifiers must be publicly available.
    • Encoding Scheme. These qualifiers identify schemes that aid in the interpretation of an element value. These schemes include controlled vocabularies and formal notations or parsing rules. A value expressed using an encoding scheme will thus be a token selected from a controlled vocabulary (e.g., a term from a classification system or set of subject headings) or a string formatted in accordance with a formal notation (e.g., "2000-01-01" as the standard expression of a date). If an encoding scheme is not understood by a client or agent, the value may still be useful to a human reader. The definitive description of an encoding scheme for qualifiers must be clearly identified and available for public use.

    All of the qualifiers listed in this document fall into one of these two categories. Additional qualifier categories may evolve over time and with implementation experience. Proposed qualifiers which appeared to the DCMI Usage Committee to fall outside of these categories, or which fell short in some other respect (e.g., clarity of definition), will become the focus of further discussion and be reconsidered for approval in the future.

    The qualifiers listed here do not constitute a closed set, designed to meet all of the descriptive needs of implementors. Rather, they form the foundation for a larger body of qualifiers that will evolve as additional qualifiers are developed by various communities and submitted to the DCMI Usage Committee for review and approval. Implementors may deploy these qualifiers with confidence that they conform to the Dumb-Down Principle, and are encouraged to use these qualifiers as examples to guide development of local qualifiers for Dublin Core metadata elements.

    Summary of Qualifiers (non-normative)

    This summary of the qualifiers is provided for the convenience of users. The reference definitions are to be found below.

    DCMES Element

    Element
    Refinement(s)

    Element
    Encoding Scheme(s)

    Title Alternative -
    Creator - -
    Subject -

    LCSH
    MeSH
    DDC
    LCC
    UDC

    Description Table Of Contents
    Abstract
    -
    Publisher - -
    Contributor - -
    Date Created
    Valid
    Available
    Issued
    Modified
    DCMI Period
    W3C-DTF
    Type - DCMI Type Vocabulary
    Format Extent
    -
    Medium IMT
    Identifier - URI
    Source - URI
    Language - ISO 639-2
    RFC 1766
    Relation Is Version Of
    Has Version
    Is Replaced By
    Replaces
    Is Required By
    Requires
    Is Part Of
    Has Part
    Is Referenced By
    References
    Is Format Of
    Has Format
    URI
    Coverage Spatial
    DCMI Point
    ISO 3166
    DCMI Box
    TGN
    Temporal DCMI Period
    W3C-DTF
    Rights - -

     

    Properties of Dublin Core Qualifiers

    Dublin Core qualifiers have the following properties:

    • Name: The unique token assigned to the qualifier.
    • Label: The human-readable label assigned to the qualifier.
    • Definition: A statement that represents the concept and essential nature of the qualifier.
    • Comment: Additional information associated with the qualifier (if available).
    • See Also: A link to more information about the qualifier (if available).

    Note that the properties of qualifiers -- in particular the terms Name and Label -- differ with respect to those defined for the Dublin Core Metadata Element Set Version 1.1. These changes reflect a decision to bring Dublin Core schema terminology in line with terminology in the XML community to promote easier integration of Dublin Core schemas in XML and RDF environments.

    Multiple Language Encodings of Dublin Core Entities

    Dublin Core qualifiers will be expressed in languages other than English. A single invariant token assigned to each qualifier -- the Name property -- stands for a given qualifier concept irrespective of the language in which it is defined. This token can be incorporated into a URI to form a unique identifier for the qualifier. All other properties of a qualifier (Label, Definition, Comment, and aspects of See Also as appropriate) can be translated from English into any other language.

    All other properties of Dublin Core entities (Label, Definition, Comment, and aspects of See Also as appropriate) will be expressed in the language and character set of the translation.

    Dublin Core Qualifiers

    Title
    The qualifiers below are recommended for the Title element.

    Qualifiers that refine Title:

    Alternative

    Name: alternative
    Label: Alternative
    Definition: Any form of the title used as a substitute or alternative to the formal title of the resource.
    Comment: This qualifier can include Title abbreviations as well as translations.

    Subject
    The qualifiers below are recommended for the Subject element.

    Encoding Schemes for Subject:

    LCSH

    Name: LCSH
    Label: LCSH
    Definition: Library of Congress Subject Headings

    MeSH

    Name: MESH
    Label: MeSH
    Definition: Medical Subject Headings
    See also: http://www.nlm.nih.gov/mesh/meshhome.html

    DDC

    Name: DDC
    Label: DDC
    Definition: Dewey Decimal Classification
    See also: http://www.oclc.org/dewey/index.htm

    LCC

    Name: LCC
    Label: LCC
    Definition: Library of Congress Classification See also: http://lcweb.loc.gov/catdir/cpso/lcco/lcco.html

    UDC

    Name: UDC
    Label: UDC
    Definition: Universal Decimal Classification See also: http://www.udcc.org/

    Description
    The qualifiers below are recommended for the Description element.

    Qualifiers that refine Description:

    Table Of Contents

    Name: tableOfContents
    Label: Table Of Contents
    Definition: A list of subunits of the content of the resource.

    Abstract

    Name: abstract
    Label: Abstract
    Definition: A summary of the content of the resource.

     

    Date
    The qualifiers below are recommended for the Date element.

    Qualifiers that refine Date:

    Created

    Name: created
    Label: Created
    Definition: Date of creation of the resource.

    Valid

    Name: valid
    Label: Valid
    Definition: Date (often a range) of validity of a resource.

    Available

    Name: available
    Label: Available
    Definition: Date (often a range) that the resource will become or did become available.

    Issued

    Name: issued
    Label: Issued
    Definition: Date of formal issuance (e.g., publication) of the resource.

    Modified

    Name: modified
    Label: Modified
    Definition: Date on which the resource was changed.

    Encoding Schemes for Date:

    DCMI Period

    Name: Period
    Label: DCMI Period
    Definition: A specification of the limits of a time interval.
    See also: http://dublincore.org/specifications/dublin-core/dcmi-period/

    W3C-DTF

    Name: W3CDTF
    Label: W3C-DTF
    Definition: W3C Encoding rules for dates and times - a profile based on ISO 8601
    See also: http://www.w3.org/TR/NOTE-datetime

    Resource Type
    The qualifiers below are recommended for the Resource Type element.

    Encoding Schemes for Resource Type:

    DCMI Type Vocabulary

    Name: DCMIType
    Label: DCMI Type Vocabulary
    Definition: A list of types used to categorize the nature or genre of the content of the resource.
    See also: http://dublincore.org/specifications/dublin-core/dcmi-type-vocabulary/

    Format
    The qualifiers below are recommended for the Format element.

    Qualifiers that refine Format:

    Extent

    Name: extent
    Label: Extent
    Definition: The size or duration of the resource.

    Medium

    Name: medium
    Label: Medium
    Definition: The material or physical carrier of the resource.

    Encoding Schemes for Format:

    IMT

    Name: IMT
    Label: IMT
    Definition: The Internet media type of the resource.
    See also: http://www.isi.edu/in-notes/iana/assignments/media-types/media-types

    Resource Identifier
    The qualifiers below are recommended for the Resource Identifier element.

    Encoding Schemes for Resource Identifier:

    URI

    Name: URI
    Label: URI
    Definition: A URI Uniform Resource Identifier
    See also: http://www.ietf.org/rfc/rfc2396.txt

    Language
    The qualifiers below are recommended for the Language element.

    Encoding Schemes for Language:

    ISO 639-2

    Name: ISO639-2
    Label: ISO 639-2
    Definition: ISO 639-2: Codes for the representation of names of languages.
    See also: http://lcweb.loc.gov/standards/iso639-2/langhome.html

    RFC 1766

    Name: RFC1766
    Label: RFC 1766
    Definition: Internet RFC 1766 'Tags for the identification of Language' specifies a two letter code taken from ISO 639, followed optionally by a two letter country code taken from ISO 3166.
    See also: http://www.ietf.org/rfc/rfc1766.txt

    Relation
    The qualifiers below are recommended for the Relation element.

    Qualifiers that refine Relation:

    Is Version Of

    Name: isVersionOf
    Label: Is Version Of
    Definition: The described resource is a version, edition, or adaptation of the referenced resource. Changes in version imply substantive changes in content rather than differences in format.

    Has Version

    Name: hasVersion
    Label: Has Version
    Definition: The described resource has a version, edition, or adaptation, namely, the referenced resource.

    Is Replaced By

    Name: isReplacedBy
    Label: Is Replaced By
    Definition: The described resource is supplanted, displaced, or superceded by the referenced resource.

    Replaces

    Name: replaces
    Label: Replaces
    Definition: The described resource supplants, displaces, or supersedes the referenced resource.

    Is Required By

    Name: isRequiredBy
    Label: Is Required By
    Definition: The described resource is required by the referenced resource, either physically or logically.

    Requires

    Name: requires
    Label: Requires
    Definition: The described resource requires the referenced resource to support its function, delivery, or coherence of content.

    Is Part Of

    Name: isPartOf
    Label: Is Part Of
    Definition: The described resource is a physical or logical part of the referenced resource.

    Has Part

    Name: hasPart
    Label: Has Part
    Definition: The described resource includes the referenced resource either physically or logically.

    Is Referenced By

    Name: isReferencedBy
    Label: Is Referenced By
    Definition: The described resource is referenced, cited, or otherwise pointed to by the referenced resource.

    References

    Name: references
    Label: References
    Definition: The described resource references, cites, or otherwise points to the referenced resource.

    Is Format Of

    Name: isFormatOf
    Label: Is Format Of
    Definition: The described resource is the same intellectual content of the referenced resource, but presented in another format.

    Has Format

    Name: hasFormat
    Label: Has Format
    Definition: The described resource pre-existed the referenced resource, which is essentially the same intellectual content presented in another format.

    Encoding Schemes for Relation:

    URI

    Name: URI
    Label: URI
    Definition: A URI Uniform Resource Identifier
    See also: http://www.ietf.org/rfc/rfc2396.txt

    Coverage
    The qualifiers below are recommended for the Coverage element.

    Qualifiers that refine Coverage:

    Spatial

    Name: spatial
    Label: Spatial
    Definition: Spatial characteristics of the intellectual content of the resoure.

    Encoding Schemes for Spatial:

    DCMI Point

    Name: Point
    Label: DCMI Point
    Definition: The DCMI Point identifies a point in space using its geographic coordinates.
    See also: http://dublincore.org/specifications/dublin-core/dcmi-point/

    ISO 3166

    Name: ISO3166
    Label: ISO 3166
    Definition: ISO 3166 Codes for the representation of names of countries
    See also: http://www.din.de/gremien/nas/nabd/iso3166ma/codlstp1/index.html

    DCMI Box

    Name: Box
    Label: DCMI Box
    Definition: The DCMI Box identifies a region of space using its geographic limits.
    See also: http://dublincore.org/specifications/dublin-core/dcmi-box/

    TGN

    Name: TGN
    Label: TGN
    Definition: The Getty Thesaurus of Geographic Names
    See also: http://shiva.pub.getty.edu/tgn_browser/

    Temporal

    Name: temporal
    Label: Temporal
    Definition: Temporal characteristics of the intellectual content of the resource.

    Encoding Schemes for Temporal:

    DCMI Period

    Name: Period
    Label: DCMI Period
    Definition: A specification of the limits of a time interval.
    See also : http://dublincore.org/specifications/dublin-core/dcmi-period/

    W3C-DTF > Name: W3CDTF
    Label: W3C-DTF
    Definition: W3C Encoding rules for dates and times - a profile based on ISO 8601
    See also: http://www.w3.org/TR/NOTE-datetime


    Acknowledgements

    This document represents the accumulated efforts of working group participants and working group chairs over a long period of time. In addition, the DCMI Usage Committee labored long and hard to integrate the efforts of these groups into a coherent recommendation. Thanks are due to these participants for the committment of their time and expertise in bringing this recommendation to fruition.

    The following are the members of the DCMI Usage Committee: Leif Andresen, Tom Baker, David Bearman, Priscilla Caplan, Warwick Cathro, Eric Childress, Simon Cox, Makx Dekkers, Rebecca Guenther, Juha Hakala, Rachel Heery, Diane Hillmann, Renato Iannella, Erik Jul, Traugott Koch, John Kunze, Carl Lagoze, Sigfrid Lundberg, Jon Mason, Eric Miller, Andy Powell, Diann Rusch-Feja, Roland Schwaenzl, Shigeo Sugimoto, Stuart Sutton, Stuart Weibel.

    Errata
    2008-11-03. Added "superseded" banner. 2018-06-12. Corrected headers after Hugo migration.