Version 2.5 25.6.1997
Metadata in general
Metadata is data which describes attributes of a resource. Typically, it supports a number of functions: location, discovery,
documentation, evaluation, selection and others. These activities may be carried out by human end-users or their (human or
automated) agents.
Dublin Core Metadata Element Set
Dublin Core homepage, maintained by the OCLC, is available at
http://purl.oclc.org/metadata/dublin_core.
DC was developed by an informal group of computer scientists, network specialist, librarians etc. The work is loosely coordinated by the OCLC and NCSA. Formal (sort of) decisions are made in Dublin Core Workshops, four of which have been arranged:
The fifth Workshop will be held in Helsinki, Finland, 6.-8.10.1997. It will concentrate on implementation issues.
There are already several active projects using DC, many of which are linked to the DC homepage. The Nordic Metadata project (see below) was probably the first one of these which covered all (or most) aspects of metadata usage.
The main idea behind the Dublin Core development was to build a metadata element set so versatile that any Internet document can be described with it, but on the other hand so simple that the authors can provide metadata by themselves.
| Table 1. The Dublin Core Elements | |
|---|---|
| Subject | The topic addressed by the work. | Description | A textual description of the content of the resource | Title | The name of the object. | Author | The person(s) primarily responsible for the intellectual content of the object. | Publisher | The agent or agency responsible for making the object available in its current form. | Other Agent | The person(s), such as editors, transcribers, and illustrators who have made other significant intellectual contributions to the work. | Date | The date of publication. | Object type | The genre of the object, such as novel, poem or dictionary. | Form | The physical manifestation of the object, such as PostScript file or Windows executable file. | Identifier | String or number used to uniquely identify the object. | Relation | Relationship to other objects. | Source | Objects, either print or electronic, from which this object is derived, if applicable. | Language | Language of the intellectual content. | Coverage | The spatial location and/or temporal duration characteristics of the object. | Rights Management | The content of this element is intended to be a link (a URL or other suitable URI as appropriate) to a copyright notice, a rights-management statement, or perhaps a server that would provide such information in a dynamic way |
Usage of most elements is reasonably clear, but some elements need more detailed usage specifications. See for instance the spec for Coverage at http://alexandria.sdc.ucsb.edu/public-documents/metadata/dc_coverage.html
Use of Identifier element is difficult without URN's!
With Scheme qualifier it is possible to specify for instance the subject heading list your subject terms have been picked from, or the identification system (like ISBN or ISSN) used to identify your document.
In the Author tag, you can tell the author's name, e-mail address, telephone number etc. from one another by using Type qualifier.
Qualifier specification is still not quite complete. A draft proposal written by Jon Knight is available at http://www.roads.lut.ac.uk/Metadata/DC-Qualifiers.html
Extensibility of the Dublin Core has also been enhanced by defining a method for using private elements. The names of these must start with "X-". Web indexing robots can then easily recognise and ignore local extensions (if they have not been taught how to use them).
WWW is the strategic application of the Internet at the moment. The Dublin Core community started therefore by specifying a generic way of embedding metadata in HTML (see http://www.oclc.org:5046/~weibel/html-meta.html). Dublin Core is just one metadata element set that can utilise this specification. The convention agreed upon is as follows:
<META NAME = "schema_identifier.element_name.qualifier" CONTENT = "string data">
Example of the Date element:
< Dublin Core has schema identifier DC, so an indexing robot will know that DC.date.current is the Dublin Core Date element, with qualifier "current". Scheme is needed for correct interpretation of of the date information.
The next step will be specification of DC syntax for TIFF or some other tagged image file format.
The Nordic Metadata project
The size of the project is 12 man months, 50.000 USD, duration 1.11.1996-31.5.1998.
The project is funded by NORDINFO (http://www.hut.fi/NORDINFO/).
The software and documentation created in the project is / will be available in public domain
Organizations are people directly involved with the project are:
| Table 2. The Project participants | |
|---|---|
| Bibsys, Norway | Ole Husby |
| Helsinki University Library, Finland | Juha Hakala |
| Lund University Library, NetLab, Sweden | Traugott Koch |
| Munksgaard, Denmark | Anders Geertsen |
| The National and University Library of Iceland | Sigbergur Fridriksson |
| Swedish Institute of Computer Science | Preben Hansen |
The Danish Library Center (http://www.dbc.dk/) is an associated partner in the project.
The project's aims are:
An example of usage of the Finnish Public Library Classification:
<META NAME= "DC.subject" CONTENT=" (SCHEME=YKL) 75">
Thanks to the DC extensibility mechanism it will be easy to incorporate Nordic specialities (if any) into our DC records should the need for this arise.
The converter will be finalised, and other Nordic MARCs added, during Summer 1997. Specification of DC -> FINMARC conversion is available at http://www.lib.helsinki.fi/meta/dcficross.html
The converted will be built in such a way that adding new MARC formats and modifying existing conversions will be easy.
The converter will be available in two guises: as a stand-alone application and as a plug-in that can be utilized as a module in other applications.
It is more difficult to convert from MARC to DC than vice versa: due to complexity of MARCit is hard to convert from MARC to anything else, including DC. We may try this later in the project, anyway.
NetLab collects also statistics on metadata usage in Scandinavia with the NWI. The results can be seen at http://www.ub2.lu.se/metadata/Nordic-MDusage.html