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'''Title:''' Audubon Core

'''Date:''' TBD. This document is a proposal

'''Abstract:''' The Audubon Core is a set of vocabularies designed to represent metadata for biodiversity multimedia resources and collections. These vocabularies aim to represent information that will help to determine whether a particular resource or collection will be fit for some particular biodiversity science application before acquiring the media. Among others, the vocabularies address such concerns as the management of the media and collections, descriptions of their content, their taxonomic, geographic, and temporal coverage, and the appropriate ways to retrieve, attribute and reproduce them. This document contains material introductory to the '''[[Audubon Core Term List]]'''

'''Contributors:''' Robert A. Morris, Vijay Barve, Mihail Carausu, Vishwas Chavan, Jose Cuarda, Chris Freeland, Gregor Hagedorn, Patrick Leary, Dimitry Mozzherin, Annette Olson, Greg Riccardi, Ivan Teage

'''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:''' TBD

'''See also:''' The [[Audubon Core Term List]] and the [[Audubon_Core_Non_normative_document]]

This document has version 1.0.1 and MRTG Wiki revision ID {{REVISIONID}} with a permalink http://species-id.net/w/index.php?title=Audubon_Core&oldid={{REVISIONID}}

The version presently under internal review is http://species-id.net/w/index.php?title=Audubon_Core&oldid=189457

Here is the '''[[Audubon Core Term List]]'''.

__TOC__ <!-- table of contents should appear here -->

[[Image:WIP.gif]]   This is the normative documentation for the [http://tdwg.org TDWG] Audubon Core Multimedia Resources Metadata Standard (Audubon Core, or simply AC), During development, it was colloquially known as MRTG, after its developers, the GBIF-TDWG Joint Multimedia Resources Metadata Task Group. Please see the brief non-normative document linked at [[Audubon Core Non normative document]] and also '''[http://www.keytonature.eu/wiki/MRTG_Development_History MRTG Development History]''' for the development history in detail. 

'''If you are unfamiliar with the AudubonCore, ''please'' read the [[Audubon Core Non normative document]] before editing this page.''' It lays out why there is perceived a need for a biodiversity media resource metadata schema, and how the standard attempts to use existing metadata standards where possible.

==Related Information==


* Go here for Discussion of the'''[http://www.keytonature.eu/wiki/XML_Schema_For_MRTG XML Schema For MRTG]'''. This is obsolete and will be revised for compliance with the normative version when it is approved.
* Go here for Discussion of the '''[http://www.keytonature.eu/wiki/MRTG_in_RDF MRTG in RDF].''' This is obsolete and will be revised for compliance with the normative version when it is approved.
* '''[http://www.keytonature.eu/wiki/TDWG09_MRTG_WORKGROUP_REPORT TDWG09 MRTG WORKGROUP REPORT]'''

==Terminology of this specification==

There are many ways to organize metadata specifications, particularly as to the nomenclature of the constituents of the metadata. In this document and the associated non-normative documentation, we will follow closely (sometimes verbatim) a portion of the Dublin Core Metadata Initiative (DCMI) metadata nomenclature as described in Section 2.3 of the DCMI Abstract Model (http://www.dublincore.org/documents/abstract-model/). In addition:

* A ''Multimedia Resource'' is anything that a provider identifies as belonging to one of the possible values of the AC ''Type'' term and one of the ''Subtype'' term values. A mechanism is provided by which providers can supply a privately defined subtype that will not collide with the AC defined Subtype values.
* An AC ''record'' is a set of terms with any values conforming to this document, and which contain at least the six mandatory terms described below, and which describes a single multimedia resource (possibly including a Collection). One of these, the value of ''Identifier'' is a Globally Unique IDentifier (GUID), which may have been assigned to the resource by an external authority or by the provider of the metadata record.
* AC terms are divided into two ''Layers''. Those characterized as in the ''Core Layer'', including the six mandatory terms, should be meaningfully handled by all consuming clients applications. Only wholly complete consuming applications need handle those in the ''Extended Layer'. 

In this document, every AC term has a Name, a URI, a plain text normative Definition, a recommended English Label,  an optional "Details" attribute, and an optional "Comments" attribute. In addition, a term has an attribute telling whether it is mandatory, one telling whether it is repeatable, and one telling whether it is in the "Core" or "Extended" Layer. The Extended Layer comprises terms likely to only occur for certain media. For example, the term ''DateAvailable'' will apply only to media that are embargoed, but for which the provider is prepared to make the metadata immediately available. 

It is strongly recommended that consuming applications be able to meaningfully handle all Core terms, and that only wholly complete consuming applications need handle Extended Layer terms. What is meant by "meaningfully handle" is up to implementers of this normative specification.  It could be as simple as "gracefully ignore". 

AC metadata can describe either individual multimedia resources or collections of resources. A few, but not many, of the AC properties have different values for collections than for individual media. If no such distinction is mentioned, AC does not assume one.

Term Names for terms borrowed from other vocabularies are those in use for the corresponding term in those vocabularies. Term names are intended principally for navigation in this document. Term Labels are suggestions for English labels in applications.  They are recommendations only and are offered only in English, with the added expectation that they may clarify intended usage of the term.  Communities may wish to promulgate recommendations for Labels in other languages, or even alternative English Labels for specialized audiences, e.g. school children.

URI's for terms conform to the http URI scheme (See, http://en.wikipedia.org/wiki/URI_scheme, http://www.w3.org/TR/uri-clarification/, or http://www.ietf.org/rfc/rfc2396.txt ). Informally, one may understand this as follows: an http URI has the syntax of an http URL, but there is no expectation that putting it in a web browser will result in any information being returned to the browser, and if there is, it may have no relevance. This conformance requirement applies only to the URIs that identify AC terms. A few AC terms permit '''values''' to be taken from another controlled vocabulary chosen by the user. In this case, those values may involve URIs conforming to a scheme given by that external vocabulary, and AC is silent on what that scheme is. 

The Details field of a term's documentation points to further information, if any exists, about the term. In particular, for terms borrowed from other vocabularies, this field generally carries a link to the originating vocabulary's documentation for that term.

==Media Collections==
A few, but not many, of the AC terms have different values for collections than for individual media. If no such distinction is mentioned, AC does not assume one.

==Multiplicity==
A number of terms do not permit repetition within a single AC metadata record, sometimes in cases where there seems a compelling case for more than one value for a term.  A typical example is the term [[#Reviewer| Reviewer]], being the name of an individual providing some natural language expert review of a resource, typically given as the value of the term [[#Reviewer_Comments | Reviewer Comments]].   Clearly, more than one person might provide such a review, but in this case something has to specify which reviewer made which comments. There are several solutions to this kind of problem, which is endemic to many kinds of descriptive metadata. One is to have some kind of linkage between the related terms. This alone is not sufficient, as we see from this example: a reviewer might make several comments, several reviewers might together make several comments, and some other group of reviewers might make some other group of comments, etc. This the linkage approach requires not only linkages between many terms, but also container objects holding multiples, and linkages between those containers and other objects. Other even more complex ways to allow aggregation of terms to provide relations between them are possible. MRTG has chosen instead to have entirely flat terminology (with the sole exception of the [[#Access_Point |Access Point]]) but this does ''not'' preclude multiple values. At the small cost of having to repeat some of the term values (including the required ones), a description can contain several metadata records for the same Multimedia Resource. Consider for example the following pseudo-code in an imaginary spreadsheet implementation of AC. In this example, the implementing language requires an additional spreadsheet term named EOR ("End of Record") separating several metadata records for the same image (because they have the same Identifier) from one another. Note that this entire issue is principally an issue for machine parsing of attribute values. Nothing in AC prevents a metadata provider from having a well documented punctuation mechanism suited for human readability that, for example, allows both a reviewer comment and reviewer name in the same text, and even multiple such pairs all in a single Reviewer_Comments. In that context, the AC multi-record approach illustrated below may be regarded as a standardized way of atomizing such a punctuation convention, and mapping back and forth between this atomization and a punctuation based single piece of text would not be difficult.
{| border="1" summary="Example spreadsheet implementation with two metadata records for the same image"
|+ align="bottom" " |''Example spreadsheet implementation with two metadata records for the same image''
! Term !! Value
|-
|Identifier ||	http://bit.ly/pwrmwD
|-
|Type ||	image
|-
| … (many terms) ||	…
|-
|Reviewer || Susan Grogan
|-
|Comments ||	Excellent Image
|-
|EOR ||	Yes
|-
|Identifier ||	http://bit.ly/pwrmwD
|-
|Type ||	image
|-
|… (required terms only)||	…
|-
|Reviewer ||	Jonathan Smythe
|-
|Reviewer Comments ||	Colors are inaccurate
|-
|EOR ||	Yes
|}

==Plain Text Lists==

Some AC terms permit values that are lists to be represented as plain text. The choice of how to
separate list items is necessarily left to the implementors of AC. For
example, an XML implementation of AC might choose to use standard XML
container methods whereas an implementer of a spreadsheet version, in which
cells may contain lists, might specify a punctuation
mark, e.g. comma, and supply some special escape syntax for use when
the comma is part of the metadata value. An implementation might even
make different such choices depending on the term involved, the languages supported, etc.

==Term List==
Go here: [[Audubon Core Term List]]