From EAD to METS

1. From EAD to METS An overview and history of METS Rick Beaubien UC Berkeley

2. EAD and Ebind • EAD originated at UCB in Berkeley Finding Aid Project: 1993-1995 • Applied in California Heritage Project (1995) • Goals: Digitize collections pertaining to CA history, create EAD finding aids for these collections, and link the EADs to the content • Linking to single component objects (painting) easy • Linking to multi-page objects (book) difficult

3. Ebind • SGML DTD developed at UCB by Alvin Pollock & Daniel Pitti • Key features • Provided means of specifying how the individual images comprising a digital version of an individual work fit together into a structured, coherent whole • Facilitated discovery of Ebind encoded digital objects • External: link to library catalog record • Internal: limited descriptive element set

4. Making of America II • DLF and NEH funded initiative commencing in 1997 • Extension of EAD work • Participants: UC Berkeley (lead), Penn State, UCLA, Stanford, NYPL • Focus: creating an integrated but distributed digital library of archival materials • Cornerstone: digital object encoding standard

5. MOA2 Development Process • Defined desired functionality of library digital objects. • Defined metadata needed to support requisite functionality • Distinguished three main types of metadata for Library Digital Objects • Structural (organize, view and navigate) • Descriptive (discovery) • Administrative (manage)

6. MOA2 Development Process • Codified the requisite metadata in an xml DTD: MOA2.DTD • XML DTD developed by Jerome McDonough • Direct predecessor of METS

7. MOA2.DTD Features • Support for content and structure • Provided for inventorying the content files • Provided for applying one or more (hierarchical) structures to the content files • Limitations: • Accommodated image and text digital content only • Structural divisions could only reference integral image content files • No part of files, sequence of files or parallel file support

8. MOA2.DTD Features • Support for discovery & description: • Defined its own descriptive element set • Allowed content at all structural levels to: • Link to external desc md (finding aid, catalog record) • Link to internal desc md • Limitation: internal descriptive element set crude, UCB centric

9. MOA2.DTD Features • Support for management & preservation • Defined its own technical, source and rights md element sets • Provided for linking content files with these elements • Provided for embedding content files directly in an MOA2 object • Limitations: admin element sets preliminary and incomplete

10. From MOA2 to METS • Response to MOA2.DTD • CDL adopts as its digital object standard • Other institutions try it • Focus on archival materials with image/text content felt to be too limited • Still, went a long ways towards meeting a need • DLF funded revision process: • Work commenced February 2001 • Participants included LoC, NYU, Harvard, UC, Stanford, OCLC, RLG, MetaE (EU), et al • Outcome: METS schema • Jerry McDonough still the principal developer

11. METS and MOA2 compared • Support for content and structure • Expands content file support: any content • Supports Audio and Video content • No longer focused on archival materials • Enhances support for relationships between structure and content: • METS structural divisions can link to: • Integral files • Parts of files (defined by coordinates/shapes, time parms, tags/ids) • Sets of files or parts of files that must be played in sequence • Sets of files or parts of files that must be played in parallel • Other structural divisions in non-hierarchical, hypertext fashion

12. METS and MOA2 compared • Support for discovery & description • Eliminates the MOA2 defined descriptive element set • Provides wrapper for externally defined descriptive element sets • Assumption: different communities need to develop own element sets for description • Numerous XML based descriptive element sets now available or in progress: MarcXML, MODS, DC, and VRA.

13. METS and MOA2 compared • Support for management & preservation • Eliminates MOA2 defined administrative elements • Provides wrappers for externally defined administrative elements • Provides 4 types of admin wrappers: tech md, source md, digital provenance md, and rights md • Assumption: different communities need to develop own technical and rights element sets

14. METS in Action • Institutions using METS • U.S: Library of Congress, California Digital Library, Harvard, MIT, RLG, NYU, Stanford, Florida Center for Library Automation, Berkeley Art Museum, Philadelphia Museum of Art, Indiana University Digital Library Program, et al • International: University of Alberta, Oxford, British Museum, Göttinger Digitalisierungs-Zentrum, National Library of Wales, National Library of Portugal, University of Graz, Biblioteca Digitale P. Albino, et al

15. METS in Action • Digital repository systems using/supporting METS • Greenstone (import and internal) • Fedora (import and export) • Dspace (import, export, possibly internal)

16. Applications of METS • Transfer syntax (SIP): exchanging digital content • Dissemination syntax (DIP): basis for presenting digital content to the end user • Preservation syntax (AIP): basis for preserving digital content in the long term

17. METS in context • Other content packaging standards standards • IMS-CP • Comes out the learning technology community • MPEG21 (DIDL) • Coming out of commercial world • More abstract than METS • XFDU (XML Formatted Data Units) • Comes out of Consultative Committee for Space Data Systems • Used METS as starting point • Geared towards packaging/exchange of scientific datasets

18. METS in context • Attempts to bring different standards together. • IEEE initiative: RAMLET • Attempt to develop a reference model that will encompass the various content packaging schemas, and facilitate cross-walking and future harmonization.

19. Links • METS homepage: http://www.loc.gov/standards/mets