MMA Version of MARC21 Elements and Vocabularies in RDF

Just posted by Diane Hillmann over at Metadata Matters.

Metadata Management Associates (MMA) is pleased to announce a new resource for the library community: The MMA version of MARC 21 elements and vocabularies in RDF, hosted by the Open Metadata Registry (OMR). Given the need for libraries to move beyond the MARC standard, and the desire for increased innovation as we move toward a successor, we felt this was a good time to make this data available to all. The MMA version of MARC 21 in RDF has been exclusively developed by Metadata Management Associates, and has not, as yet, been shared with the Library of Congress, although the recent announcements on MARC made it even more desirable to move in this direction.

So why did we spend the time to do this, given the intention to leave MARC behind? Most importantly, we want to make it easier for innovators to ‘play’ with this data, and to have URIs to use when they do so. We ourselves want to include MARC21 elements in our research into semantic mapping between bibliographic namespaces, and to inform proposed work on representing UNIMARC in RDF. We also want to provide inspiration for those eager to experiment with the issues around the transition from MARC 21 to the new environment of RDA and other bibliographic standards, and trust that the reassurance that it WILL happen–and is not rocket science–will help everyone interested in participating in that future.

What you see in the OMR now is what we’re calling ‘Level0’, the most basic loss-less way to transition MARC 21 data into the Resource Description Framework (RDF). It does not reflect the layers we think ought to be added on top:

  • Level1 may contain properties that gather sub-properties with similar semantics from Level0.
  • Level2 may contain properties and classes that represent aggregated statements composed of sub-properties from Level0 and Level1.
  • Level3+ can contain properties and classes that represent broader-level semantics and provide equivalence mappings to other namespaces for bibliographic metadata, such as Dublin Core terms, ISBD, and RDA.

Special thanks to Karen Coyle, whose work on the analysis of MARC 21 (most recently seen in Code4Lib Journal) inspired us greatly and whose questions pushed us in some important directions. Karen’s insights and ideas will be far more visible in Level1 and subsequent levels, when we build on the basics.

This initiative is also intended to inform the proposal to develop an RDF representation of MARC 21’s cousin, UNIMARC, presented at IFLA this year.

Please note that not all MARC21 elements are currently represented in the OMR. Some of the lesser-used tags in 00X-8XX have not yet been registered, and we are still looking into 76X-78X Linking entry fields.

We welcome feedback on this effort. Information on errors and specific issues is best communicated via the “FEEDBACK” links on all OMR pages. We’re happy to participate in discussions on the DCMI/RDA Task Group discussion list (, or anywhere else–just be sure we know that you’ve posted something, and we’ll respond.

Those of you headed for the DC-2011 conference are likely to see us presenting information on our new mapping initiative, and demonstrating how the MARC21 data in RDF supports useful mapping from MARC21 to RDA. We’ll post slides and links after that conference.

Metadata Management Associates
Diane Hillmann
Jon Phipps
Gordon Dunsire