Metadata: Dublin Core metadata
A large number of standards have been developed to describe of electronic sources. The majority of these describe highly specific sources and has a complex set-up. This complicates the accessibility and dissemination of these standards. A standard with a relatively simple structure, which is accepted and used worldwide, is the Dublin Core standard.
The Dublin Core standard serves the exchangeability with metadata standards for other applications, such as archiving.
Why Dublin Core metadata?
- Dublin Core is a standard geared to improve the findability of sources.
- It is easy to implement and to have indexed.
- Its use promotes findability, interoperability and standardisation of sources.
- Dublin Core is applied internationally and has a relatively simple structure. It is suitable for use in combination with other, more complex metadata standards, like Record Keeping Metadata, Topic Maps and the Web Ontology Language (OWL).
Dublin Core terms
The Dublin Core metadata set version 1.1 consists of 15 elements for the description of electronic information.
- author or creator
- subject and keyword
- other contributor
- resource type
- resource identifier
- rights management
In certain cases, these elements are not sufficient to adequately describe sources. Likewise, there may be a need for more specific descriptions. It is possible to define refinements or sub-elements, which are more specific. The refinements themselves, however, are not part of the Dublin Core standard. However, the way in which elements can be refined is specified in Dublin Core.
Scheme is used to describe the notation method or the permitted content value. One example is the date notation in the W3C DTF format:
If notation follows a particular pattern, (indexation) applications can use this to good effect. If the pattern is not used, the string that has been filled in will be seen as a piece of independent text that can only be interpreted and manipulated by human intelligence.
In addition, Scheme can be used to refer to a list of permitted values, a vocabulary encoding scheme. In this case too, independent text is not an option, the content must correspond to one of the values in the vocabulary encoding scheme.
HTML for specifying metadata
The 15 elements mentioned above are preceded by the code
DC. - this indicates the Dublin Core standard.
Example of Dublin Core metadata in HTML
<meta name="DC.description" content="ICTU advises government organisations to use metadata">
The content, description, depends on the element: when the element description is used, the content is a description/summary of the cdocument content.
Metadata can be added to an HTML document as follows.
- The metadata is included in the HTML source code within the
- A link to an external file is included. This is not covered in this chapter, nor is adding metadata to multimedia, or metadata from databases. The application of metadata in this way requires the use of a sound metadata management system. If such a system is not available, we advise against this option.