DLF Session: "METS Profiles"
Second in a series of reports from the Digital Library Federation 2005 Spring Forum: a session entitled "METS Profiles."
Metadata Encoding and Transmission Standard (METS) is a metadata schema designed to capture structural information about complex information resources. The Library of Congress (LC), which manages the standard, has been moving aggressively to develop “profiles” for certain classes of materials. These profiles indicate a range of information on how to apply the schema. Cundiff’s presentation focused mainly on a current LC application of profiles to the problem of describing compact discs (CDs); Keith’s presentation was dedicated to the discussion of how to make such profiles “machine –actionable.”
Cundiff described how the Model Object Description Standard (MODS) schema used to provide descriptive metadata within the METS framework can convey structural information of its own. LC has decided to intellectually divide the hierarchies expressed within CDs (and one would presume, other formats) into two baskets: a logical hierarchy and a physical hierarchy. MODS covers the logical, METS’s
For the profile, rules are created to intellectually link the hierarchies. For example, the Keith’s presentation began by indicating some of the weaknesses of METS profiles in their current form. They do not support validation of documents against the profile, and they need human intervention to decode their requirements. The flexibility of METS works against the use of profiles as currently designed. He expects an eventual workflow in which a subject expert will write a prose profile, and then a developer will use that document to create a machine-readable version. He demonstrated some early attempts at the solution using XSLT transformations.
This allows extremely flexible display and linking options, and is being put to use in their “I Hear America Singing” project. However, this type of description is extremely resource intensive and would likely only be suitable for collections undergoing “selective enhancement.”