As the number, size and complexity of metadata standards continues to grow, supplying metadata for each standard becomes repetitious, time consuming and tedious. In order to minimize the amount of time needed to create and maintain metadata and to maximize usefulness to the widest community of users, there is a need for the metadata created and maintained in one standard to be accessible via related content standards. As methods of mapping one metadata standard to another, crosswalks provide the ability to make contents of elements defined in one standard available to communities using related standards. In this case, the crosswalk would enable users of MARC to translate between it and the Dublin Core or GILS and vice versa. The fifteen elements of the Dublin Core constitute a set of unqualified descriptive metadata.
All elements are optional and repeatable.
When compared with the large number of elements available in MARC, they seem inadequate. The creators of the Dublin Core have attempted to address this by allowing the elements to be qualified. This narrows the focus of the element and allows for a more specific mapping between standards. An example of a mapping between MARC and the Dublin Core is the Dublin Core tag Contributor. The Dublin Core defines Contributor as an entity responsible for contributing to the content of the resource.