The METS Editorial Board just met and discussed your change request. The consensus among the Board members was that RDF by itself did not represent a good MDTYPE value. There were two basic issues. One is that RDF is more of a framework or model for representing arbitrary metadata schema, as opposed to a metadata schema itself. For example, RDF is used for lots of different metadata schema; Dublin Core can be represented in RDF, SKOS is an RDF schema, OAI-ORE is an RDF schema, and so is the Open Annotation standard, and many others. So just by using RDF you still have a lot of uncertainty regarding what kind of metadata a section contains. A second argument is that MIMETYPE might be a better way to advertise that the wrapped metadata uses the RDF model, especially since there is an official MIME Type for RDF XML: application/rdf+xml. So for example, if you were wrapping some specific RDF-based metadata schema, you could use something like this:
<mdWrap MDTYPE="OTHER" MIMETYPE="application/rdf+xml" OTHERMDTYPE="SOME_SPECIFIC_RDF_SCHEMA">
Let me know if you would like additional clarification.
METS Board, Technical Co-chair
From: Metadata Encoding and Transmission Standard [mailto:[log in to unmask]] On Behalf Of Vicky Phillips
Sent: Wednesday, August 14, 2013 6:38 AM
To: [log in to unmask]
Subject: Re: [METS] METS schema change requests
Would it also be possible to include RDF as a recognised MDTYPE attribute value? At present we are placing this as follows MDTYPE="OTHER"
OTHERMDTYPE="RDF" but as we use RDF in all our METS documents it would be nice to have this as a recognised value so that we could place it as follows...
National Library of Wales