METS and IMS-CP Convergence and Divergence Rick Beaubien UC Berkeley Library
What is METS? • Metadata Encoding and Transmission Standard • An XML schema-based specification for encoding “hub” documents for materials whose content is digital. • Hub doc draws together potentially dispersed but related files and data
What is METS? • METS uses XML to provide a vocabulary and syntax for identifying the digital components that together comprise a digital object, for specifying the location of these components, and for expressing their structural relationships.
METS History • Pre-MOA2 (pre-1997) • 1994-1996: UCB begins to digitize Bancroft Library’s archival collections • MOA2.dtd (1997-2001) • Preliminary digital object standard • Just image and text content • METS.xsd (2001-now) • MOA2 expanded beyond image and text content
Materials Targeted • Pictorial, manuscript & print materials • Goal: enable creation of integral digital analogues to library’s primary, physical holdings • Sound Recordings • Film/Video • Born digital • Material of any format library might be asked to archive • Websites, Learning objects, etc.
Uses of METS • Transfer Syntax • OAIS: SIP • Dissemination Syntax • OAIS: DIP • Archiving Syntax • OAIS: AIP
Who’s Using METS • Institutions • USA: • California Digital Library, UC Berkeley, Berkeley Art Museum, RLG, Stanford, U. Chicago, OCLC, U. Florida, Harvard, MIT, NYU, Philadelphia Museum of Art, Library of Congress • International: • Unversity of Alberta, British Library, Oxford University Library, National Library of Wales, University of Graz, Austria, Gottingen Digitaliserungs-Zentrum • Projected: Australia, New Zealand, Japan
Who’s Using METS • Repository/Collection Management Systems • Fedora (METS import) • Greenstone • DSpace • Commercial • docWorks
What’s Available • Selection of currently available METS objects and METS supported sites.
Linked Communities • Rich assortment of digital library materials is becoming available in METS format. • Potential content pool for learning objects • Learning objects are being deposited in libraries. • Libraries archiving learning objects in METS-based repositories.
METS Anatomy • <metsHdr> METS Header • <dmdSec> Descriptive Metadata • <amdSec> Admin Metadata • <fileSec> Content File Inventory • <structMap> Structural Map(s) • <structLink> Structural Links • <behaviorSec> Behaviors
mets metsHdr dmdSec amdSec fileSec fileGrp file structMap div structLink behaviorSec manifest metadata organizations organization metadata item metadata resources resource metadata file Convergence
Divergence • Content vs. Presentation • mets: tends to make strong distinction between content and presentation • manifest: presentation is content • Result: • mets <fileSec> and manifest <resources> only superficially similar • mets segregates presentation in optional <behaviorSec>
Implications • mets to manifest transformations • easy if content is browser ready (jpeg, gif) • more difficult if content is not: • transformation must intuit appropriate presentation from content type (example: MrSid) • manifest to mets transformations • easy just to wrap manifest in mets • difficult to turn manifest into mets
Other issues: metadata • No METS-defined element set. • METS Board endorses schemas that represent community standards. • LOM will be endorsed • Lossless mapping problems: • Some METS extension schemas fuller than LOM • LOM has learning object specific md
Other issues: profiles • METS is intentionally very flexible • few controlled vocabularies • many structural options • Problem: crosswalk can’t account for all options • Solution: profiles • Machine actionable profiles not yet supported
Union? • Complete union between METS and IMS-CP may be difficult • both standards now have momentum behind them • Basis for easier accommodation? • Adjust METS <fileSec> so it can be used like manifest <resources> element. • Add manifest style <resources> element to <mets>? • Look to METS as applied to WebSites
Links • METS Home Page. http://www.loc.gov/standards/mets/ • METS Registry. http://sunsite.berkeley.edu/mets/registry/ • METS Diagram. http://sunsite.berkeley.edu/mets/diagram
Links • UCB Candidate METS Profiles. http://sunsite.berkeley.edu/mets/ucbprofiles/ • MOA2 Project. http://sunsite.berkeley.edu/moa2/ • FEDORA. http://www.fedora.info/ • Greenstone. http://www.greenstone.org/cgi-bin/library
Links • Dspace. http://dspace.mit.edu/ • DocWorks. http://www.ccs-gmbh.de/ • OAIS Reference Model. http://www.rlg.org/longterm/oais.html