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

EAD and Ebind EAD originated at UCB in Berkeley Finding Aid Project: 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

Ebind SGML DTD developed at UCB by Alvin Pollock & Daniel Pitti Key features 1. Provided means of specifying how the individual images comprising a digital version of an individual work fit together into a structured, coherent whole 2. Facilitated discovery of Ebind encoded digital objects External: link to library catalog record Internal: limited descriptive element set

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

MOA2 Development Process 1. Defined desired functionality of library digital objects. 2. 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)

MOA2 Development Process 3. Codified the requisite metadata in an xml DTD: MOA2.DTD XML DTD developed by Jerome McDonough Direct predecessor of METS

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

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

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

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

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

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.

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

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

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

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

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

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.

Links METS homepage: