1. Introduction
The Darwin Core is body of standards. It includes a glossary of terms (in other contexts these might be called properties, elements, fields, columns, attributes, or concepts) intended to facilitate the sharing of information about biological diversity by providing reference definitions, examples, and commentaries. The Darwin Core is primarily based on taxa, their occurrence in nature as documented by observations, specimens, samples, and related information. Included are documents describing how these terms are managed, how the set of terms can be extended for new purposes, and how the terms can be used. The normative document for the terms [RDF-NORMATIVE] is written in the Resource Description Framework (RDF) and is the definitive resource to understand the term definitions and their relationships to each other. The Simple Darwin Core [SIMPLEDWC] is a specification for one particular way to use the terms - to share data about taxa and their occurrences in a simply structured way - and is probably what is meant if someone suggests to "format your data according to the Darwin Core".
2. Motivation
The Darwin Core standard was originally conceived to facilitate the discovery, retrieval, and integration of information about modern biological specimens, their spatiotemporal occurrence, and their supporting evidence housed in collections (physical or digital). The Darwin Core today is broader in scope and more versatile. It is meant to provide a stable standard reference for sharing information on biological diversity. As a glossary of terms, the Darwin Core is meant to provide stable semantic definitions with the goal of being maximally reusable in a variety of contexts.
3. Rationale
The Darwin Core is based on the standards developed by the Dublin Core Metadata Initiative [DCMI] and can be viewed as an extension of the Dublin Core for biodiversity information. The purpose of these terms is to facilitate data sharing by providing a well-defined standard core vocabulary in a flexible framework to minimize the barriers to adoption and to maximize reusability. The terms described in this standard are a part of a larger set of vocabularies and technical specifications under development [TDWG-DEV] and maintained by Biodiversity Information Standards (TDWG) [TDWG-STANDARDS].
4. Guiding principles
Each term has a definition and commentaries that are meant to promote the consistent use of the terms across applications and disciplines. Evolving commentaries that discuss, refine, expand, or translate the definitions and examples are referred to through links in the Comments attribute of each term. This means of documentation allows the standard to adapt to new purposes without disrupting existing applications. There is meant to be a clear separation between the terms defined in this standard and the applications that make use of them. For example, though the data types and constraints are not provided in the term definitions, recommendations are made about how to restrict the values where appropriate.
5. Content
The standard consists of a vocabulary of terms (properties, elements, fields, concepts) [TERMS], the policy governing the maintenance of these terms [NAMESPACEPOLICY], the decisions that resulted in changes to terms [DECISIONS], the complete history of terms including detailed attributes [HISTORY], a Generic Darwin Core XML schema [TERMSXMLSCHEMA] from which other schemas can be constructed, a Simple Darwin Core XML schema [SIMPLEXMLSCHEMA] as a complete schema ready for use, a schema to allow Darwin Core data transfer in text files [TEXTSCHEMA], and associated reference schemas for the construction of more structured content. These pages also describe mappings between the current standard and pre-standard historical versions [VERSIONS], including mappings [DWCTOABCD] to concepts in the Access to Biological Collections Data standard [ABCD].
6. Extension
Though the Darwin Core is insufficient for the needs of all biological disciplines, it can be adapted to serve new purposes. Darwin Core can be extended by adding new terms to share additional information. To do so you should be familiar with the recommendations and procedures defined in the Darwin Core Namespace Policy [NAMESPACEPOLICY]. Basically, before proposing a new term, consider the existing terms in this and other compatible standards to determine if the new concept can be accommodated by a simple revision of the description and comments for an existing term, without losing the existing meaning of that term.
7. Participation
To receive notification of activity or participate in discussions about Darwin Core, join the tdwg-content mailing list [TDWG-CONTENT] and watch the Darwin Core Project [DWC-PROJECT]. For discussion or commentary on the definition of recommended terms, consult the link inside the Comment section in the listing for the term in the Quick Reference Guide [TERMS] or search for the relevant content in the auxiliary Darwin Core Documentation [DWC-WIKI].
To make a formal request for a change to or addition of a term to the Darwin Core, read and follow the recommendations in the Darwin Core Namespace Policy [NAMESPACEPOLICY]. For those who wish to construct and submit as a standard any application profile, such as an XML schema, that extends the capabilities of the Darwin Core, adding new terms to the Darwin Core vocabulary that don't already exist in a compatible vocabulary will be a prerequisite. Consult the appropriate guideline, such as the XML Guide [XMLGUIDE], for information about the construction of a new application profile. The rules of submission of proposed standards can be found in the Biodiversity Information Standards (TDWG) process document [PROCESS].