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Darwin Core Namespace Policy

Title: Darwin Core Namespace Policy
Date Issued: 2009-02-12
Date Modified: 2009-07-06
Abstract: All terms in the Darwin Core must be assigned a unique Uniform Resource Identifier (URI). For convenience, the term URIs that are assigned and managed by the Darwin Core Task Group are grouped into collections known as Darwin Core namespaces. This document describes how term URIs are allocated by the Darwin Core Task Group and the policies associated with Darwin Core namespaces.
Contributors: John Wieczorek (MVZ), Markus Döring (GBIF), Renato De Giovanni (CRIA), Tim Robertson (GBIF), Dave Vieglais (KUNHM)
Legal: This document is governed by the standard legal, copyright, licensing provisions and disclaimers issued by the Taxonomic Databases Working Group.
Part of TDWG Standard: ***URL to DwC Standard*** will go here
Creator: Darwin Core Task Group
Identifier: http://rs.tdwg.org/dwc/2009-07-06/terms/namespace/
Latest Version: http://rs.tdwg.org/dwc/terms/namespace/
Replaces: http://rs.tdwg.org/dwc/2009-05-25/terms/namespace/
Document Status: For Public Review.

1. Introduction

Audience: This document is targeted toward those who want to make changes to the Darwin Core, either by refining terms that already exist or by adding new terms to increase the capabilities of the standard.

This document and the policies contained herein are modeled on the Dublin Core Metadata Initiative Namespace Policy [DCMINAMESPACEPOLICY]. All terms in the Darwin Core must be identified with a unique Uniform Resource Identifier (URI). For convenience, the term URIs are grouped into collections known as Darwin Core namespaces. This document describes the policies associated with Darwin Core namespaces and how term URIs are allocated by the Darwin Core Task Group [DWC-TASK].

2. Namespace URIs

The Darwin Core namespace URI for the collection of all Darwin Core properties, classes, and encoding schemes is:

http://rs.tdwg.org/dwc/terms/

The Darwin Core namespace URI for the collection of classes in the Darwin Core Type Vocabulary [DWC-TYPE] is:

http://rs.tdwg.org/dwc/dwctype/

All future Darwin Core namespace URIs (additional Darwin Core controlled vocabularies for example) will conform to this pattern:

http://rs.tdwg.org/dwc/namespace_label/

The term identifier for the current (recommended) version of a term is a URI based on the namespace and the term name without version information. Some example Darwin Core term identifiers follow:

http://rs.tdwg.org/dwc/terms/scientificName

is the Darwin Core term identifier for the scientificName property.

http://rs.tdwg.org/dwc/dwctype/PreservedSpecimen

is the Darwin Core term identifier for the PreservedSpecimen class in the Darwin Core Type Vocabulary.

All Darwin Core identifiers will dereference to a Darwin Core term declaration for the identified term.

3. Term Change Policy

Changes to Darwin Core terms or term declarations will occur from time to time for a variety of reasons. Such changes have varying implications for Darwin Core term URIs and Darwin Core namespaces. The classes of changes are identified and explained in the following sections along with examples and associated implications.

Any change to Darwin Core terms or term declarations will result in an update to the versioning information carried in the Darwin Core recommendation and/or Darwin Core term declaration associated with that term. Specifically, a new version of the term will be created with appropriate information in the Version, Replaces, and DateModified attributes of the new term, and with the identifying version information of the new term in the Is Replaced By attribute of the term being updated.

3.1. Minor editorial errata

Errors of spelling, punctuation, or other clerical mistakes discovered in Darwin Core recommendations and/or Darwin Core term declarations will be corrected without a comment period, following notification to the TDWG Architecture Group [DWC-USAGE], as long as, in the judgment of the TDWG Architecture Group, there are no implications for negative impact on users or applications that rely on those Darwin Core term declarations. Minor editorial changes of this type will result in no changes to Darwin Core term URIs, will not undergo a request for comments, and will not result in a decision [DECISIONS].

3.2. Substantive editorial errata

Errors of substance discovered in Darwin Core recommendations and/or Darwin Core term declarations will trigger public notification of the correction to the Darwin Core mailing list [DWC-SUBSCRIBE]. Errors that, in the judgment of the TDWG Architecture Group, compromise the immediate usefulness or accuracy of systems based on Darwin Core will be corrected immediately (for example, an incorrect URL to a resource external to Darwin Core). Others will be corrected following a 30-day public comment period to assure that changes do not adversely effect systems or applications which rely on the Darwin Core namespace infrastructure. Substantive editorial changes of this type will result in no changes to Darwin Core term URIs, and will not result in a decision [DECISIONS].

3.3. Semantic changes in Darwin Core terms

Changes of definitions within Darwin Core recommendations and/or Darwin Core term declarations will be reflected in the affected Darwin Core recommendation and/or Darwin Core term declaration. Semantic changes of this type will undergo a request for comments, and will result in a decision [DECISIONS]. If, in the judgment of the TDWG Architecture Group, such changes of meaning are likely to have substantial impact on either machine processing of Darwin Core terms or the functional semantics of the terms, then these changes will be reflected in a change of URI for the Darwin Core term or terms in question. The URIs for any new Darwin Core namespaces resulting from such changes will conform to the Darwin Core namespace URI pattern defined above.

Requests for semantic changes to a term should be made to the Technical Architecture Group [DWC-USAGE], and should consist of a complete list of attributes to be changed along with a statement of justification for the changes.

3.4. Addition of Darwin Core term declarations to existing Darwin Core namespaces

New terms may be added to existing Darwin Core namespaces based on public demand. Addition of terms to existing Darwin Core namespaces will not trigger changes in Darwin Core Namespace URIs. Additional term requests that have been determined by the Technical Architecture Group to have merit will undergo a request for comments and will not result in a decision [DECISIONS].

Requests for additional terms should be made to the Technical Architecture Group [DWC-USAGE], and should consist of a complete list of attributes as given in the term definitions section of the Darwin Core Terms Complete History [HISTORY] along with a statement of justification for the new term, including an explanation of why no existing term will suffice.

4. Persistence Policy

TDWG recognizes that people and applications depend on the persistence of formal documents and machine processable schemas that have been made publicly available. In particular, the stability of Darwin Core term URIs and Darwin Core namespace URIs is critical to interoperability over time. Thus, the wide promulgation of this set of URIs dictates that they be maintained to support legacy applications that have adopted them.


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