Using Metadata Standards in Digital Libraries Implementing METS

Using Metadata Standards in Digital Libraries: Implementing METS, MODS, PREMIS and MIX: Introduction Rebecca Guenther Library of Congress LITA Standards IG Program, ALA Annual 2007

Program overview • Introduction To METS, MODS, PREMIS and MIX (Guenther) • Using METS and MODS for presentations of LC content (Cundiff, Trail) • Using METS in special collections at CDL (Tingle) • Creating rich shareable metadata: the DLF Aquifer MODS implementation guidelines (Shreeves) • METS, MODS and PREMIS, Oh My!: Integrating digital library standards for interoperability and preservation (Habing) • MODS as metadata Hub (Olson)

Metadata standards in digital libraries • XML is the de-facto standard for metadata descriptions on the Internet • Interoperability and object exchange requires the use of established standards • Many digital objects are complex and are comprised of multiple files • Complex digital objects require many more forms of metadata than analog for their management and use • Descriptive • Technical • Digital provenance/events • Structural • Rights/Terms and conditions

Descriptive metadata: MARCXML • Millions of rich descriptive records in MARC systems: can be reused in an XML environment using MARCXML • MARCXML uses the MARC data element set in an XML syntax • Allows interoperability with other XML schemes by taking advantage of free XML tools • Allows for collaborative use of metadata for access (e. g. OAI) • Provides continuity with current data and flexible transition options

MARC 21 evolution to XML

MARCXML • MARCXML record – XML exact equivalent of MARC (2709) record – Lossless/roundtrip conversion to/from MARC 21 record – Simple flexible XML schema, no need to change when MARC 21 changes – Presentations using XML stylesheets – LC provides converters (open source) • http: //www. loc. gov/standards/marcxml • Music record in MARCXML

What is MODS? • Metadata Object Description Schema • An XML descriptive metadata standard • A derivative of MARC – Uses language based tags – Contains a subset of MARC data elements – Repackages elements to eliminate redundancies • MODS does not assume the use of any specific rules for description • Element set is particularly applicable to digital resources

Uses of MODS • Extension schema to METS – Rich description works well with hierarchical METS objects • To represent metadata for harvesting (OAI) – Language based tags are more user friendly • As a specified XML format for SRU • As a core element set for convergence between MARC and non-MARC XML descriptions • For original resource description in XML syntax that is simpler than full MARC

MODS high-level elements • • • Title Info Name Type of resource Genre Origin Info Language Physical description Abstract Table of contents Target audience • • • Note Subject Classification Related item Identifier Location Access conditions Part Extension Record Info Music record in MODS

MODS Development • Developed 2002 through open listserv discussion of possible implementers (LC coordinated) • Version 1 in late 2002; now in version 3. 2 with 3. 3 almost complete • Companion for authority metadata (MADS) in version 1. 0 (2005) • Endorsed as METS extension schema for descriptive metadata section • Registered with NISO • Widely used in digital library projects • MODS Implementation registry: http: //www. loc. gov/mods/registry. php

What is METS? • METS records the (possibly hierarchical) structure of digital objects, the names and locations of the files that comprise those objects, and the associated metadata • A container for metadata and file pointers • A METS document may be a unit of storage or a transmission format • METS is extensible and modular, using “wrappers” or “sockets” where elements from other schemas can be plugged in • METS uses the XML Schema facility for combining vocabularies from different Namespaces

What is PREMIS? • A data dictionary for metadata to support the long-term preservation of digital objects – A piece of the necessary infrastructure for implementing reliable, sustainable preservation programs • A supporting set of XML schema for implementation in a variety of contexts • A maintenance activity hosted at LC including an Implementers’ Group and Editorial Committee

What is preservation metadata? Preservation Metadata • Provenance: – Who has had custody/ownership of the digital object? Content • Authenticity: – Is the digital object what it purports to be? • Preservation Activity: 10 years on 50 years on – What has been done to preserve the digital object? Forever! • Technical Environment: – What is needed to render and use the digital object? • Rights Management: – What IPR must be observed? Ø Makes digital objects self-documenting across time

Guiding principles and assumptions … • “Implementable, core, preservation metadata”: – “Preservation metadata”: maintain viability, renderability, understandability, authenticity, identity in a preservation context – “Core”: What most preservation repositories need to know to preserve digital materials over the long-term – “Implementable”: rigorously defined; supported by usage guidelines/recommendations; emphasis on automated workflows • Implementation neutral: – No assumptions on specific implementation – Promote flexibility/interoperability – Focus on semantic units: what you need to know (implementation-neutral) vs. metadata elements: how you record it (implementation-specific) – Information that needs to be “recoverable” from the digital archiving system, independent of local implementation

Scope • What PREMIS is: – Common data model for organizing/thinking about preservation metadata – Guidance for local implementations – Standard for exchanging information packages between repositories • What PREMIS is not: – Out-of-the-box solution: need to instantiate as metadata elements in repository system – All needed metadata: excludes business rules, formatspecific technical metadata, descriptive metadata for access, non-core preservation metadata – Lifecycle management of objects outside repository – Rights management: limited to permissions regarding actions taken within repository

PREMIS data model Intellectual Entities Rights Agents Objects Events

Semantic units pertaining to objects: technical metadata • • object. Identifier preservation. Level object. Category object. Characteristics creating. Application original. Name storage environment • • signature. Information relationship linking. Event. Identifier linking. Intellectual Entity Identifier • linking. Permission Statement. Identifier

Semantic units pertaining to Events: provenance and preservation activity • • event. Identifier event. Type event. Date. Time event. Detail event. Outcome. Detail linking. Agent. Identifier linking. Object. Identifier

Semantic units pertaining to Rights: terms and conditions · permission. Statement. Identifier · related. Object · granting. Agent · granting. Agreement · permission. Granted · act · restriction · term. Of. Grant · permission. Note

Semantic units pertaining to Agents • agent. Identifier • agent. Name • agent. Type

PREMIS maintenance activities • First revision of Data Dictionary (PREMIS 2. 0) – Documenting errata and proposed revisions to Data Dictionary (feedback through PIG list) – http: //www. loc. gov/standards/premis/changes. html • PREMIS Implementers’ Registry – http: //www. loc. gov/standards/premisregistry. html • Consultancies (funded by Library of Congress): – Rights issues for digital preservation (Karen Coyle) – PREMIS implementation guidelines and recommendations (Deborah Woodyard-Robinson) • PREMIS Tutorials: – Glasgow, Boston, Stockholm, Albuquerque, Washington

What is MIX? • Metadata For Images in XML • An XML Schema designed for expressing technical metadata for digital still images • Based on the NISO Z 39. 87 Data Dictionary – Technical Metadata for Digitial Still Images • Used to express attributes of digital images such as file format, file size, dimensions, resolution, compression, etc. • Version 1. 0 (recently released) includes support for GIS images and JPEG 2000 images; data element names harmonized with PREMIS • Can be used standalone or as an extension schema with METS

How do these standards work together for digital libraries? • A container format such as METS allows for packaging together forms of metadata with objects or pointers to objects • There about 5 years of experimentation experience using METS in combination with other standards for managing and using digital objects in digital libraries • These standards are all freely available • METS profiles detail how METS is used for particular object types or applications • Best practices are needed (and being developed) for use of PREMIS with METS and MIX • Using METS, MODS, PREMIS and MIX: http: //www. loc. gov/premis/louis. xml