Standards showcase: MODS, METS, MARCXML ALA Annual 2006 Rebecca Guenther and Jackie Radebaugh Network Development and MARC Standards Office Library of Congress

Overview of presentation Metadata in general MARC and the XML environment MODS Uses Features Projects METS introduction Examples of METS/MODS use

XML “XML has become the de-facto standard for representing metadata descriptions of resources on the Internet.” Jane Hunter Working towards MetaUtopia - A Survey of Current Metadata Research

The importance of standards “In moving from dispersed digital collections to interoperable digital libraries, the most important activity we need to focus on is standards… most important is the wide variety of metadata standards [including] descriptive metadata… administrative metadata…, structural metadata, and terms and conditions metadata…” Howard Besser The Next Stage: Moving from Isolated Digital Collections to Interoperable Digital Libraries

Metadata Data about data Structured information used to aid identification, description, management and location of resources Also may include physical resources Earliest form: Catalog record

Why MARC in XML? Importance of descriptive metadata in current environment Large investments in MARC systems Retooling to make use of the flexibility of XML Libraries may receive records using other metadata schemes in XML Collaborative use of metadata for access OAI harvesting SRU (Web service based on Z39.50)

Evolution of MARC 21 Take advantage of XML Establish standard MARC 21 in an XML structure Take advantage of freely available XML tools Develop simpler (but compatible) alternatives MODS Allow for interoperability with different schemas Assemble coordinated set of tools Provide continuity with current data Provide flexible transition options

MARC 21 evolution to XML

MARC 21 in 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)

Example: MARC and MARCXML Music record in MARC Music record in MARCXML

What is MODS? Metadata Object Description Schema Descriptive metadata standard Initiative of Network Development and MARC Standards Office at LC Uses XML Schema language Originally designed for library applications, but may be used for others A derivative of MARC

Potential Uses of MODS As a rich (but not too rich) XML metadata format for emerging initiatives specified XML format for SRU extension schema to METS to represent metadata for harvesting (OAI) 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

Advantages of MODS Element set is compatible with existing descriptions in large library databases Element set is richer than Dublin Core but simpler than full MARC Language tags are more user-friendly than MARC numeric tags Hierarchy allows for rich description, especially of complex digital objects Rich description that works well with hierarchical METS objects

Features of MODS Uses language-based tags Elements have same definitions as equivalent MARC elements Elements are particularly applicable to digital resources MODS does not assume the use of any specific rules for description Element descriptions are reused throughout the schema Use of XML schema allows for flexibility and availability of freely available tools

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

Example: MODS Music record in MODS

Status of MODS Open listserv collaboration of possible implementors, LC coordinated (1 st half 2002) First comment and use period: June – December 2002 Now in MODS version 3.2 Registration approved by National Information Standards Organization (NISO) Companion for authority metadata (MADS) in version 1.0

LC uses of MODS Describing electronic resources Digital library projects using METS (e.g. LC Presents, Blackmun papers) Archived web sites: Example (HTML)Example XML NDNP OAI collections LC offers MODS, MARCXML, DC simple

A selection of MODS projects University of Chicago Library Chopin early editions Finding aid discovery Digital Library Federation Aquifer initiative National Library of Australia MusicAustralia: MODS as exchange format between National Library of Australia and ScreenSoundAustralia Australian national bibliographic database metadata project Many more at MODS Implementation registry Implementation registry

Additional metadata: enter METS Explosion of digital resources requires additional metadata Structural Administrative Preservation Rights Need for packaging metadata and objects together Hierarchical features of MODS and METS work well together

What is METS? (schema) METS is an XML Schema designed for the purpose of creating XML documents that express the hierarchical structure of digital library objects, the names and locations of the files that comprise those objects, and the associated metadata.

What is METS? (document)  A unit of storage  A transmission format  An OAIS information package  An “active information source” (application)

What are some characteristics of METS?  METS is:  an open standard  non-proprietary  developed by the library community  (relatively) simple  extensible  modular

What are the Main Sections of a METS Document?

Linking in METS Documents (XML ID/IDREF links) DescMD mods relatedItem AdminMD techMD sourceMD digiprovMD rightsMD fileGrp file StructMap div fptr div fptr

Linking in METS Documents (XML ID/IDREF links) DescMD mods relatedItem AdminMD techMD sourceMD digiprovMD rightsMD fileGrp file StructMap div fptr div fptr

Linking in METS Documents (XML ID/IDREF links) DescMD mods relatedItem AdminMD techMD sourceMD digiprovMD rightsMD fileGrp file StructMap div fptr div fptr

Linking in METS Documents ( XML ID/IDREF links) DescMD mods relatedItem AdminMD techMD sourceMD digiprovMD rightsMD fileGrp file StructMap div fptr div fptr

Linking in METS Documents ( XML ID/IDREF links) DescMD mods relatedItem AdminMD techMD sourceMD digiprovMD rightsMD fileGrp file StructMap div fptr div fptr

METS extension schemas “wrappers” or “sockets” where elements from other schemas can be plugged in Provides extensibility Uses the XML Schema facility for combining vocabularies from different Namespaces Endorsed extension schemas: Descriptive: MODS, DC, MARCXML Technical metadata: MIX (image); textMD (text) Preservation related: PREMIS

The Descriptive Metadata Section (dmdSec) Two methods: Reference and Wrap

Descriptive metadata Section with mdWrap Example 4 Example 5 Example 6

METS/MODS examples Patriotic melodies Recorded event

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