General Metadata Standards for Resource Discovery
Dublin
Core
The Dublin Core (DC) is the most widely used metadata standard
for resource discovery. Developed by the Dublin
Core Metadata Initiative (an open forum composed of individuals
from diverse disciplines and from all over the world), the Dublin
Core is intended to be simple to use, and general enough to
be applied to resources in any discipline. The Dublin Core
defines the categories of information to record about a resource
(such as a Web page, a document, or an image) in order for the
resource to be easily 'discovered'. It has been approved as an ANSI standard (Z39.85-2001), an ISO standard (15836), and has been adopted within the Canadian, Australian, and UK governments among others.
The Dublin
Core Metadata Element Set
consists of 15 elements, which
include Title, Creator, Subject, Description, Publisher, Contributor,
Date, Type, Format, Identifier, Source, Language, Relation, Coverage,
and Rights. These 15 elements are designed for simple resource
discovery. However, in some applications, it may be necessary
to refine or qualify the meanings of the Dublin Core metadata.
A model called the Qualified
Dublin Core has been developed to refine the meanings
of simple Dublin Core elements through the use of element
qualifiers or encoding schemes. For example, the DC.Date element
can be refined to DC.Date.Created. Qualifiers can refine the meanings
of Dublin Core elements, but not extend them.
It is recognized that the Dublin Core will not cover the potential
needs of all users, and will not be sufficient for purposes other
than simple resource discovery (for example, Dublin Core
will not handle all of the information needed for museum collections
management or documentation, rights management, etc.). However,
it is intended that local implementations or communities of users
(such as the museum community) will use Dublin Core as
the "core", and develop their own extensions to meet their discipline-specific
or local needs. In practice, this often happens the other way
around - the museum will use a discipline-specific standard (such
as the CHIN
Data Dictionaries or SPECTRUM)
in order to document and manage their collections, and extract
a subset of their collections records which map to the Dublin
Core Elements. These Dublin Core records can then be used
for purposes of data exchange and simple resource discovery. This
is particularly important for sharing data across disciplines,
or in collaborative projects. The Dublin Core Metadata Element
Set is also available in French.
There are various Dublin
Core Working Groups (e.g. Education, Architecture, Administration,
Collection Description, etc.) working on the development of discipline-specific
element sets to supplement the "core" elements. The Dublin Core
Education Working Group has had an education-specific Dublin Core
element set approved, with additional elements such as "Audience".
Guidelines to help users in the creation of Dublin Core
metadata have been developed and are available in English
and French.
The Dublin Core is becoming more and more widely used in the
museum field. The Consortium for the Interchange of Museum Information
(CIMI) has tested the effectiveness of Dublin Core for museum
data in the CIMI Dublin Core Testbed Project. CIMI has published
a Guide
to Best Practice:Dublin Core 1.1 for museums, available
in English only.
CHIN has completed a mapping from selected
fields of the Humanities Data Dictionary to the Dublin Core
Elements. CHIN has used the Dublin Core in several
of its recent initiatives
and in its involvement with CIMI
testbeds. For example, museums that catalogue their learning
resources in CHIN's Learning With Museums are generating
Dublin Core metadata for their resources. CHIN is also
including Dublin Core metadata in some of its Web pages.
The Dublin Core Metadata Initiative has drafted a Dublin
Core Metadata Glossary which may be helpful.
Darwin
Core
Darwin Core (DwC) is a "profile describing the minimum
set of standards for search and retrieval of natural history collections
and observation databases"1.
Darwin Core is one of a series of tools developed for The
Species Analyst, a research project "developing standards
and software tools for access to the world's natural history collection
and observation databases"2
which is based at the University of Kansas Natural History Museum
and Biodiversity Research Center. As noted on the Darwin Core
Web site, "there is a commonality in the content of almost all
collection and observation databases which may be exploited to
perform ordered search and retrieval from these diverse data sets.
The Darwin Core attempts to provide a set of guidelines
for addressing this commonality regardless of the underlying mechanism
for storing the record content"3.