Metadata can be defined as:

  • Data that describes one or more resources, or as
  • Data that is connected to an object and describes said object.
In general, metadata is a description of documents, objects or services, and contains information about content, structure or form of the same. In a more abstract way, metadata describes data or "data about data". Bibliographical sets of data and catalogue entries in libraries can be seen as a form of metadata.

The basis for the metadata in OPUS is a Dublin Core Metadata Element Set (in short Dublin Core or DC) which consists of a maximum of 15 basic elements. It is the result of international efforts to find common ground to describe electronic documents.

All metadata that has been entered in OPUS is summarised in the Front door. For OPUS publications, the front door is the first page with the link to the full text. The metadata contains necessary details about the content and a formal description of the document. Once members of staff of the University Library have formally checked the bibliographical details, they will be added to the OPUS server and thus be made publically accessible. In the process, the bibliographical data is also adjusted to current standards for alphabetical cataloguing in academic libraries.

In addition to the metadata in the front door, OPUS publications also contain metadata directly in the PDF document. When you do the PDF conversion, please ensure that the document properties contain useful details at least about the Title and Author. Go to File -> Properties or File -> Document properties. Search machines pull this metadata from the PDF files; it will show up in the search results.