SPS Home    >   Dgreath    >   Dublin Core Metadata

Dublin Core Metadata

Dublin Core metadata provides a standard indexing scheme for the Semantic Web. The original or unqualified core metadata assumes all content values are literal strings,  that language is irrelevant, and that there is no distinction between repeated elements (a date is a date) all of which is perfectly fine for loose keyword style indexing. True semantic indexing, however, requires either a structural specifications or controlled vocabularies which necessitates schema declaration, distinction of languages, and distinction of difference between repeated elements (date created is distinct from date modified).

Therefore, there are three additional metadata aspects needed to qualify a core element:

  • specification of language for internationalization,
  • specification and use of structural specifications and controlled vocabularies, and
  • specification of element qualifiers.

Internationalization is specified using the xml:lang="en-US" attribute of the meta element. Recommend best practice is to follow RFC-3066, which in conjunction with ISO-639 and ISO-3166, defines two and three letter primary language tags with optional country codes. However, if a language has been specified in either the html or head element, the xml:lang attribute should not be included in each meta element generally unless the specific element requires specification of a different language. Best practice, therefore, is to specify the default language in the html element and omit the xml:lang attributes except where needed.

Specification and use of structural specifications or controlled vocabularies are denoted using the scheme="DCTERMS.W3CDTF" attribute of the meta element. Recommended practice is to specify using values of the NMTOKEN data-type as specified in the DCMI "terms" namespace.

Specification of element qualifiers is accomplished by appending appropriate qualifiers to DC elements using the dot delimiter in the form name="DC.date.modified". Generally, nonstandard or local qualifiers are ignored and should not be used unless there is a specific need.

Dublin Core elements may be repeated as many times as necessary.

A collection of controlled vocabularies and XML/RDF files is available at http://purl.org/scc-wc/

Note, however, that there are issues in conversion of XHTML qualified metadata into RDF structures as Dublin Core lacks the necessary structure to embed schema.

Unqualified Dublin Core Metadata

The following table presents the original fifteen unqualified Dublin Core (DC) elements in a cut and paste format with explanatory notes. The head element declares that the document contains Dublin Core markup. The link element provides the necessary semantic link to element definitions.  Each desired DC element is included in a separate XHTML meta element and can be repeated as necessary.  Unqualified DC is suitable for simple description but should not be used where semantic indexing is the primary intent due to its inherent limitations.

Note 1- Contributor
A person or organization who contributed to the content of this resource.
Note 2 - Coverage
The spatial, temporal, or jurisdictional extent or scope of the content of this resource.
Note 3 - Creator
The person or organization primarily responsible for making the content of this resource.
Note 4 - Date
A date associated with the creation or availability of this resource.
Note 5 - Description
An account of the content of this resource, typically an abstract or table of contents.
Note 6 - Format
The physical or digital manifestation of this resource frequently used to determine the software, hardware, or other requirements needed to use it.
Note 7 - Identifier
An unambiguous reference to this resource within a given context.
Note 8 - Language
The language of the intellectual content of this resource.
Note 9 - Publisher
The person or organization responsible for making this resource available.
Note 10 - Relation
A reference to a another resource related in some way to this resource.
Note 11 - Rights
A statement about rights held in and over this resource.
Note 12 - Source
A reference to a resource from which this resource was derived.
Note 13 - Subject
The topic of the content of this resource.
Note 14 - Title
A name given to this resource by which it is formally known.
Note 15 - Type
The nature or genre of the content of this resource.

Qualified Dublin Core Metadata

Note 1- Contributor
An entity responsible for making contributions to the content of this resource and can be either a person or organization.
* Recommended practice is to list the individual's surname first followed by the given name or, for organizations, the name in full. The schema would be XSD.String. Another alternative would be to set schema to DCTERM.URI and list the url of the contributors's website or FOAF.
 
Note 2 - Coverage
The extent or scope of the content of this resource and can be described spatially, temporally, or jurisdictionally.
* Recommended practice is to either select a value from a controlled vocabulary or describe it using a structural specification.
Qualifiers:
.spatial
Spatial characteristics of the content of this resource.

Qualified Temporal Schemes:
DCTERMS.Box
A structural specification describing a region of space using its geographic bounds.
DCTERMS.ISO3166
A controlled vocabulary of names of countries.
DCTERMS.Point
A structural specification describing a point in space using its geographic coordinates.
DCTERMS.TGN
A controlled vocabulary of geographic names..
.temporal
Temporal characteristics of the content of this resource.

Qualified Temporal Schemes:
DCTERMS.Period
A structural specification describing the limits of a time interval e.g content="name=foo; start=YYYY-MM-DD; end=YYYY-MM-DD; scheme=W3C-DTF;".
DCTERMS.W3CDTF
A structural specification describing dates and times based on ISO-8601  e.g. content="YYYY-MM-DD" decimal format.
Note 3 - Creator
An entity primarily responsible for making the content of this resource and can be either a person or organization.
* Recommended practice is to list the individual's surname first followed by the given name or, for organizations, the name in full. The schema would be XSD.String. Another alternative would be to set schema to DCTERM.URI and list the url of the creator's website or FOAF.
 
Note 4 - Date
A date associated with the creation or availability of this resource.
* Recommended practice is to follow a structural specification to describe either instances or intervals.
 
Qualifiers:
.available
Date, often a range, that this resource will or did come available.
.created
Date of creation of this resource.
.dateAccepted
Date of acceptance of this resource (i.e. of thesis by university department, of article, or article by journal, etc.).
.dateCopyrighted
Date of submission of this resource (i.e. thesis, articles, etc.).
.dateSubmitted
Date of statement of copyright.
.issued
Date of formal issuance (i.e. publication) of the resource.
.modified
Date on which the resource was changed.
.valid
Date (often a range) of validity of a resource.
Qualified Schemes:
DCTERMS.Period
A structural specification describing the limits of a time interval e.g content="name=foo; start=YYYY-MM-DD; end=YYYY-MM-DD; scheme=W3C-DTF;"..
DCTERMS.W3CDTF
A structural specification describing dates and times based on ISO-8601 e.g. content="YYYY-MM-DD" decimal format.
Note 5 - Description
An account of the content of this resource and may include but is not limited to an abstract, table of contents, or a free-text account of this content. Scheme should be XSD.string
 
Qualifiers:
.abstract
A summary of the content of this resource.
.tableOfContents
A list of the subunits of the content of this resource.
Note 6 - Format
The physical or digital manifestation of this resource frequently used to determine the software, hardware, or other requirements needed to display or operate this resource.
Format may include the media-type, medium, or extent of the resource.
* Recommended best practice is to select a value from a controlled vocabulary.

Qualifiers:
.extent
The size or duration of this resource.
.medium
The material or physical carrier of this resource.
Qualified Schemes:
DCTERMS.IMT
A controlled vocabulary of Internet Media Types that define computer media formats (e.g. "text/html" or "text/css").
XSD.String
Extent and medium can be expressed as simple strings.
Note 7 - Identifier
An unambiguous reference to this resource within a given context.
* Recommended best practice is to identify this resource by means of a string or number conforming to a formal identification system. Example formal identification systems include the Uniform Resource Identifier (URI), the Digital Object Identifier (DOI), and the International Standard Book Number (ISBN). The DOI is a fully qualified Internet resource however ISBN is not.
Qualifiers:
.bibliographicCitation
A bibliographic reference for this resource.
* Recommended best practice is to include sufficient bibliographic detail to identify this resource as unambiguously as possible whether or not the citation is in a standard form. Normally, this would include the missing publication information such as the publication title, volume, issue, and page numbers, etc but not information otherwise referenced in other meta elements.
Qualified Schemes:
DCTERMS.URI
A structural specification describing online Internet resources (Uniform Resource Identifier).
XSD.String
Suitable for offline identification information.
Note 8 - Language
The language of the intellectual content of this resource.
* Recommended practice is to use RFC3066, which in conjunction with ISO639 defines two and three letter primary language tags with optional subtags. Examples include "en" or "eng" for English, "aak" for Akkadian, and "en-GB" for English used in the United Kingdom.
Qualified Schemes:
DCTERMS.ISO639-2
A controlled vocabulary of names of languages maintained by the International Standards Organization (ISO). Use this scheme to indicate the full name of the language e.g. "English."
DCTERMS.RFC1766
A structural specification describing a means of specifying languages in a two by two token format e.g. "en-US". (Note: This specification is non-preferred.)
DCTERMS.RFC3066
A structural specification describing a means of specifying languages in either a two by two token e.g. "en-US" or three by two token e.g. "eng-US". Use the three by two token only when a two by two token is not available. (Note: This specification is preferred.)
Note 9 - Publisher
An entity responsible for making this resource available and can be either a person or organization.
* Recommended practice is to list the individual's surname first followed by the given name or, for organizations, the name in full. The schema would be XSD.String. Another alternative would be to set schema to DCTERM.URI and list the url of the publisher's website or FOAF.

Note 10 - Relation
A reference to a related resource. Related resources accessible via the Internet are qualified relations, those that are not are unqualified.
* Recommended practice is to reference this resource by means of either a string or number conforming to a formal identification system or a URI as follows:
 
Qualifiers:
.conformsTo
This resource conforms to the specified established standard.
.hasFormat
This resource pre-existed the referenced resource which is essentially the same intellectual content presented in another format.
.hasPart
This resource either physically or logically includes the referenced resource .
.hasVersion
This resource has a version, edition, or adaptation, namely, the referenced resource.
.isFormatOf
This resource is the same intellectual content as the referenced resource, but presented in another format, i.e. a web version of a print source.
.isPartOf
This resource is a physical or logical part of the referenced resource.
.isReferencedBy
This resource is referenced, cited, or otherwise pointed to by the referenced resource.
.isReplacedBy
This resource is supplanted, displaced, or superceded by the referenced resource.
.isRequiredBy
This resource is either physically or logically required by the referenced resource.
.isVersionOf
This resource is a version, edition, or adaptation of the referenced resource. (Note: changes in version imply substantive changes in content rather than differences in format.)
.references
This resource references, cites, or otherwise points to the referenced resource.
.replaces
This resource supplants, displaces, or supersedes the referenced resource.
.requires
This resource requires the referenced resource to support its function, delivery, or coherence of content.
Qualified Schemes:
DCTERMS.URI
A structural specification describing Internet resources (Uniform Resource Identifier) for qualified relations.
XSD.String
Suitable for describing unqualified relations.
Note 11 - Rights
Information about rights held in and over this resource.
Typically, a Rights element will contain a rights management statement for this resource, or a reference a a service providing such information. Rights information often encompasses Intellectual Property Rights (IPR), copyright and various property rights. If the Rights statement is absent, no assumptions can be made about the status of these and other rights with respect to this resource.
 
Qualifiers:
.accessRights
Information about who can access this resource or an indication of its security status.
Access rights may include information regarding access or restrictions based on privacy, security, or other regulations.
Possible security status indicators and their meanings:
Unclassified (black border documents)
Information may be freely disclosed.
Restricted (green border documents)
Unclassified information that may be disclosed only to authorized persons.
Confidential (blue border documents)
Information capable of causing damage if disclosed.
Secret (red border documents)
Information capable of causing significant damage if disclosed.
Top Secret (orange border documents)
Information capable of causing exceptionally grave damage if disclosed.
.license
A legal document giving official permission to do something with this resource.
Recommended best practice is to identify the license using a URI. Examples of such licenses can be found at the Creative Commons website.
Qualified Schemes:
DCTERMS.URI
A structural specification describing Internet resources (Uniform Resource Identifier) for qualified rights.
XSD.String
Suitable for describing unqualified rights.
Note 12 - Source
A reference to a resource from which the present resource derived.
The present resource may be derived from the Source resource in whole or in part. Recommended best practice is to reference the resource by means of a string or number conforming to a formal identification system.
Qualified Schemes:
DCTERMS.URI
A structural specification describing Internet resources (Uniform Resource Identifier) suitable for qualified sources.
XSD.String
Suitable for describing unqualified sources.
Note 13 - Subject
The topic of the content of this resource.
Typically, a Subject will be expressed as keywords, key phrases, or classification codes that describe the topic of this resource. Recommended best practice is to select a value from a controlled vocabulary or formal classification scheme such as:
DCTERMS.DDC
The controlled vocabulary of the Dewey Decimal Classification system.
DCTERMS.LCC
The controlled vocabulary of classifications by the Library of Congress.
DCTERMS.LCSH
The controlled vocabulary of subject headings by the Library of Congress.
DCTERMS.MESH
The controlled vocabulary of medical subject headings by the National Institutes of Health.
DCTERMS.NLM
The controlled vocabulary of medical classifications by the National Institutes of Health.
DCTERMS.UDC
The controlled vocabulary of Universal Decimal Classification system.
Note 14 - Title
A name given to this resource by which it is formally known and expressed as a text string.
 
Qualifiers:
.alternative
Any form of the title used as a substitute or alternative the formal title of this resource.
This qualifier can include Title abbreviations as well as translations.
Note 15 - Type
The nature or genre of the content of this resource.
Type includes terms describing general categories, functions, genres, or aggregation levels for content. Recommended best practice is to select a value from a controlled vocabulary (for example the DCMI Type Vocabulary). [Note: to describe the physical or digital manifestation of this resource, use the Format element.]
Qualified Schemes:
DCTERMS.DCMIType
A controlled vocabulary of types used to categorize the nature or genre of the content of this resource. The qualified DCMITypes are:
DCMIType.Collection
An aggregation of items. The term Collection means that the resource is described as a group; however,  its respective parts may be separately described and navigated.
DCMIType.Dataset
Information encoded in a defined structures such as lists, tables or databases and intended to be used for direct machine processing.
DCMIType.Event
A non-persistent, time-based occurrence.
DCMIType.Image
A symbolic visual representation (other than text) such as images, photographs of physical objects, paintings, prints, drawings,other images and graphics, animations and moving pictures, film, diagrams, maps, and musical notation and may be in both electronic or physical representations.
DCMIType.InteractiveResource
A resource which requires interaction from the user to be understood, executed, or experienced.
DCMIType.MovingImage
A series of visual representations that, when shown in succession, impart an impression of motion such as animations, movies, television programs, videos, zoetropes, or visual output from a simulation.
DCMIType.PhysicalObject
A inanimate three-dimensional object or substance.
DCMIType.Service
A system that provides one or more functions of value to an end user.
DCMIType.Software
A computer program either in source or compiled form which may be available for installation non-transiently on another machine.
DCMIType.Sound
A resource whose content is intended to be rendered as audio.
DCMIType.StillImage
A static visual representation such as paintings, drawings, graphic designs, plans, and maps.
DCMIType.Text
A resource whose content is primarily words for reading.
 
Note 16 - AccrualMethod
The method by which items are added to a collection.
* Recommended best practice is to select a value from a controlled vocabulary.
 
Note 17 - AccrualPeriodicity
The frequency with which items are added to a collection.
* Recommended practice is to select a value from a controlled vocabulary.
 
Note 18 - AccrualPolicy
The policy governing the addition of items to a collection.
* Recommended practice is to select a value from a controlled vocabulary.
 
Note 19 - Audience
A class of entity for whom the resource is intended or useful and may be determined by the Creator, Publisher, or by a third party.
* Recommended practice is to select a value from a controlled vocabulary.
 
Qualifiers:
.educationLevel
A general statement describing the education or training context. Alternatively, a more specific statement of the location of the audience in terms of its progression through an education or training context.
.mediator
A class of entity that mediates access to this resource and for whom the resource is intended or useful.
The audiences for a resource are of two basic classes: (1) an ultimate beneficiary of this resource, and (2) frequently, an entity that mediates access to this resource. The mediator qualifier represents the second of these two classes.
Note 20 - InstructionalMethod
A process, used to engender knowledge, attitudes, and skills, that the resource is designed to support. Instructional Method will typically include ways of presenting instructional materials or conducting instructional activities, patterns of learner-to-learner and learner-to-instructor interactions, and mechanisms by which group and individual levels of learning are measured. Instructional methods include all aspects of the instruction and learning processes from planning and implementation through evaluation and feedback.
 
Note 21 - Provenance
A statement of any changes in ownership and custody of this resource since its creation that are significant for its authenticity, integrity, and interpretation expressed as a text string. The statement may include a description of any changes successive custodians made to this resource. The XSD.string scheme is appropriate for this.
 
Note 22 - RightsHolder
A person or organization owning or managing the rights to this resource.
* Recommended practice is to use the URI or name of the Rights Holder to indicate the entity. List the individual's surname first followed by the given name or, for organizations, the name in full. The schema would be XSD.String. Another alternative would be to set schema to DCTERM.URI and list the url of the rightsholder's website or FOAF.

Dublin Core Metadata Template

The following table provides a cut and paste rendition of the various DC elements including language specification, complete schema specification, and qualifiers: