Data providers and curators provide a great deal of metadata with their data file. This metadata is invaluable for users and for Virtual Observatory software developers. In order to be interoperable, the metadata must refer to common data models. A new specification is being developed by the IVOA Data Modeling Working Group to define a scheme for annotating VOTable instances in a standard, consistent, interoperable fashion, so that each piece of metadata can unambiguously refer to the correct data model element it expresses. With this specification data providers can unambiguously and completely represent metadata in the VOTable format as data model instances, and clients can build faithful representations of such instances. The mapping can be extended to formats other than VOTable.
Link to PDF (may not be available yet): P10-6.pdf