What is METS?

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

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

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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

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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

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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

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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)

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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

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MARC 21 evolution to XML
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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)
• http//www.loc.gov/standards/marcxml

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Example MARC and MARCXML

• Music record in MARC
• Music record in MARCXML

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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

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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

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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

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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

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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

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Example MODS

• Music record in MODS

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Status of MODS

• Open listserv collaboration of possible
  implementors, LC coordinated (1st 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

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LC uses of MODS

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

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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
  http//www.loc.gov/mods/registry.php

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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

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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.
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What is METS? (document)

• A unit of storage
• A transmission format
• An OAIS information package
• An active information source (application)

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What are some characteristics of METS?

• METS is
• an open standard
• non-proprietary
• developed by the library community
• (relatively) simple
• extensible
• modular

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What are the Main Sections of a METS Document?
ltmetsgt ltdmdSec/gt ltamdSec/gt ltfileSec/gt
ltstructMap/gt lt/metsgt
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Linking in METS Documents(XML ID/IDREF links)

• DescMD
• mods
• relatedItem
• relatedItem

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

• DescMD
• mods
• relatedItem
• relatedItem

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

• DescMD
• mods
• relatedItem
• relatedItem

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

• DescMD
• mods
• relatedItem
• relatedItem

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

• DescMD
• mods
• relatedItem
• relatedItem

AdminMD techMD sourceMD digiprovMD rightsMD
fileGrp file file
StructMap div div fptr div fptr
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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

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The Descriptive Metadata Section (dmdSec)
Two methods Reference and Wrap
ltmetsgt ltdmdSecgtlt/dmdSecgt ltfileSecgtlt/fileSecgt
ltstructMapgtlt/structMapgt lt/metsgt
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Descriptive metadata Section with mdWrap
ltmetsgt ltdmdSecgt ltmdWrapgt
ltxmlDatagt lt!-- insert data from different
namespace here --gt lt/xmlDatagt
lt/mdWrapgt lt/dmdSecgt ltfileSecgtlt/fileSecgt
ltstructMapgtlt/structMapgt lt/metsgt
Example 4 Example 5 Example 6
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METS/MODS examples

• Patriotic melodies
• Recorded event

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For further information
http//www.loc.gov/standards/mods http//www.loc.g
ov/standards/mets http//www.loc.gov/marcxml