Standards showcase:

MODS, METS, MARCXMLALA 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)

http://www.loc.gov/standards/marcxml

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 (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

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

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

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?

<mets> <dmdSec/> <amdSec/> <fileSec/> <structMap/></mets>

Linking in METS Documents(XML ID/IDREF links)

DescMDmods

relatedItemrelatedItem

AdminMDtechMDsourceMDdigiprovMDrightsMD

fileGrpfilefile

StructMap

div

div

fptr

div

fptr

Linking in METS Documents(XML ID/IDREF links)

DescMDmods

relatedItemrelatedItem

AdminMDtechMDsourceMDdigiprovMDrightsMD

fileGrpfilefile

StructMap

div

div

fptr

div

fptr

Linking in METS Documents(XML ID/IDREF links)

DescMDmods

relatedItemrelatedItem

AdminMDtechMDsourceMDdigiprovMDrightsMD

fileGrpfilefile

StructMap

div

div

fptr

div

fptr

Linking in METS Documents(XML ID/IDREF links)

DescMDmods

relatedItemrelatedItem

AdminMDtechMDsourceMDdigiprovMDrightsMD

fileGrpfilefile

StructMap

div

div

fptr

div

fptr

Linking in METS Documents(XML ID/IDREF links)

DescMDmods

relatedItemrelatedItem

AdminMDtechMDsourceMDdigiprovMDrightsMD

fileGrpfilefile

StructMap

div

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)

<mets> <dmdSec></dmdSec> <fileSec></fileSec> <structMap></structMap></mets>

Two methods: Reference and Wrap

Descriptive metadata Section with mdWrap

<mets> <dmdSec> <mdWrap> <xmlData>

<!-- insert data from different namespace here --> </xmlData> </mdWrap> </dmdSec> <fileSec></fileSec> <structMap></structMap></mets>

Example 4Example 5 Example 6

METS/MODS examples

Patriotic melodies Recorded event

For further information

http://www.loc.gov/standards/mods

http://www.loc.gov/standards/mets

http://www.loc.gov/marcxml