1 Metadata 101 Amy Benson NELINET, Inc. November 7, 2005.
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Transcript of 1 Metadata 101 Amy Benson NELINET, Inc. November 7, 2005.
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Standards
Increase interoperability Lower use and participation barriers Build larger communities of users which can
drive creation of a wider range of relevant services and tools (Windows vs Mac)
Improve chances of long term survival of materials
Prefer open over proprietary
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Categories
Metadata containers– XML, RDF
Metadata standards– MARC, MODS, DC, EAD, TEI, ONIX, FGDC, GILS
Metadata content standards Transmission standards and protocols
– METS, OAI, SOAP, Z39.50, SRW Identifiers
– URI, URL, PURL, URN, DOI, ISTC
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Metadata - What is it?
Data about data Information about any aspect of a resource -
size, location, attributes, topic, origin, use, audience, creator, quality, access rights, reviews… the list is endless
An aid to the discovery, identification, assessment, and management of described entities
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Types of Metadata
Descriptive– What is it?
Discovery– How can I find it?
Structural– What files comprise it?
Administrative– When was it created?
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Types of Metadata
Identifiers– How can I get to it?
Terms & conditions– Can I use it?
Preservation– Which key characteristics of the resource need to
be maintained?
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MARC
Advantages– Rich set of descriptive elements– Highly interoperable within library community– Long, established history
Disadvantages– Low extensibility– As is, not interoperable beyond the library world– Weak on administrative, rights, and other kinds of
metadata important for digital resources
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MARC
Future of MARC– Must MARC die? No. New life through XML
MARC XML from the Library of Congress (LC) MODS: a version of MARC encoded in XML,
developed by the Library of Congress Crosswalks between MARC and many other
metadata schemas already exist
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MARC XML
LC has developed a MARC XML schema, stylesheets, and tools
The schema allows representation of a complete MARC record in XML– Lossless conversion
Will support new transformations to new uses of MARC data– MARC to MARCXML to Dublin Core and MODS
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Metadata Object Description Schema (MODS)
Set of 20 bibliographic elements - a subset of the MARC 21 Format for Bibliographic Data
Not as complete as the full MARC format, but richer than Dublin Core (for example)
Highly interoperable with existing MARC records Uses language-based tags, rather than numbers like
MARC 21 (245, 650, etc.) Under development by the LC Network Development
and MARC Standards Office
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MODS
XML-based– Intended to work with/complement other metadata
formats
Can be used for conversion of existing MARC records or to create new resource description records
Useful particularly for library applications that want to go beyond the OPAC
Shares features of MARC and Dublin Core
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MODS Elements
TitleInfo Name TypeOfResource Genre PublicationInfo Language PhysicalDescription Abstract TableOfContents TargetAudience
Note Cartographics Subject Classification RelatedItem Identifier Location AccessCondition Extension RecordInfo
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MODS Elements
Title element is mandatory, all others are optional
Elements can have subelements and attributes which provide refining detail for the element
Elements and sub-elements are repeatable, except in certain cases
Elements display in any order
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MODS Implementation
MODS User Guidelines– http://www.loc.gov/standards/mods/registry.html
MODS Implementation Registry Contains descriptions of MODS projects
planned, in progress, and fully implemented– http://www.loc.gov/standards/mods/registry.html
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Dublin Core (DC)
A method of describing resources intended to facilitate the discovery of electronic resources
Designed to allow simple description of resources by non-catalogers as well as specialists
National and International standard– ANSI/NISO standard Z39.85-2001– ISO standard 15836
Includes 15 “core” elements
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Dublin Core Elements
Title Creator Subject Description Publisher Contributor Date Type
Format Identifier Source Language Relation Coverage Rights
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Dublin Core
All elements optional and repeatable Elements display in any order Authority control not required Simple and Qualified DC Extensible Flexible International
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Dublin Core
Simple– Lowest common denominator– Less rich– Discovery role – leads to resource or more complete
description of resource
Qualified– More precise– Less interoperable
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Dublin Core Examples
Generic
Title=“The sound of music” HTML
<meta name = "DC.Title" content = “The sound of music”>
XML<?xml version="1.0"?> <metadata
xmlns:dc="http://purl.org/dc/elements/1.1/"><dc:title> The Sound of Music</dc:title> </metadata>
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Other Metadata Standards
Encoded Archival Description (EAD) Text Encoding Initiative (TEI) Visual Resources Association (VRA) Global Information Locator Service (GILS) Online Information Exchange (ONIX) Content Standards for Digital Geospatial
Metadata (CSDGM) aka FGDC Document Data Initiative (DDI)
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Crosswalks
Crosswalks map an element from one scheme to its closest equivalent in another scheme– Example: MARC 1XX field is mapped to DC ‘creator’
Instrumental for converting data in one format to another format - one that is potentially more widely accessible
Support the demand for cross-domain searching and interoperability
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Crosswalks
There is rarely a one-to-one correlation between elements of different schemes– One to many - DC to MARC– Many to one or none - MARC to DC– None to one or many
MARC to DC– http://www.loc.gov/marc/marc2dc.html#unqualif
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Content Standards
AACR (Anglo-American Cataloguing Rules)– “The rules cover the description of, and the
provision of access points for, all library materials commonly collected at the present time.”
– The current text is the 2nd ed, 2002 Revision (with 2003, 2004, and 2005 updates)
– The Joint Steering Committee for Revision of AACR (JSC) is working on a new code, “RDA: Resource Description and Access” scheduled to be published in 2008
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Content Standards
International Standard Bibliographic Description (ISBD)– A family of standards to regularize the form and
content of bibliographic descriptions– Available for different material types: monographs,
computer files, etc.– Designed to promote record sharing and exchange
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Content Standards
Describing Archives: A Content Standard (DACS)– Designed to facilitate consistent, appropriate, and
self-explanatory description of archival materials and creators of archival materials
– Replaces Archives, Personal Papers, and Manuscripts (APPM)
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Metadata Encoding & Transmission Standard (METS)
A system for packaging metadata necessary for both the management of digital library objects within a repository and the exchange of such objects between repositories, or between repositories and their users
Used for: Digital collection repositories Developed by the Digital Library Federation
(DLF) and Library of Congress (LC)
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Metadata Encoding & Transmission Standard (METS)
METS can be understood as a binder that unites metadata about a particular resource
A METS record includes six parts:– Header– Descriptive metadata– Administrative metadata– File groups– Structural map– Behavior section
100 Pixel GIF
800 Pixel JPG
1400 Pixel JPG
2000 Pixel JPG TIFF PDF TEI MrSid AIFF
Whole DocumentPage 1Page 2Page 3Page 4
Object Components(21 Files and counting…)
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METS Schema
m etsHdr(M E TS
H ead er)
dm dSec(D esc rip t iveM etad a ta )
am dSec(A d m in s tra tive
M etad a ta )
fileSec(F iles )
structM ap(S tru c tu re )
behaviorSec(V iew ers )
MET S
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Open Archives Initiative (OAI)
A tool that supports interoperability among multiple databases
OAI goal: coarse-granularity resource discovery
OAI handles simple discovery from multiple community-specific repositories with metadata crosswalked to unqualified Dublin Core
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OAI
Roots are in the science community interested in locating and searching multiple repositories of pre- and e-prints of scientific papers
Not really an archive, the way we traditionally think of the word
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OAI
Data providers expose (make available) the metadata for their collections
Service providers harvest the exposed metadata and aggregate it (so that one search does it all) and/or provide additional services related to the harvested metadata, such as providing easy access to recent additions, updated materials, pre-set searches, etc.
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OAI
OAI Protocol for Metadata Harvesting– Metadata content must be encoded in XML and
have a corresponding XML schema for validation– Metadata must be supplied in unqualified Dublin
Core format, at least– Other metadata formats are optional– Metadata may optionally include a link to the actual
content / resource
OAI Infrastructure
repository
repository
repository
repository
Harvester
Service Provider
DC
DC
DC
DC
DC
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Z39.50
Z39.50 is a search and retrieval protocol, maintained by LC, capable of operating over TCP/IP
Negotiates queries with multiple, separate databases – does not harvest + create new db
Built in to some library software systems OAI not intended to replace other approaches, but
to provide an easy-to-use alternative for different constituencies and purposes
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Search/Retrieve Web Service
The primary function of SRW is to allow a user to search remote databases of records
Protocol uses easily available technologies -- XML, SOAP, HTTP, URI -- to perform tasks traditionally done using proprietary solutions such as database queries and responses
Builds on Z39.50 and moves it forward– ZING: Z39.50 International: Next Generation
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Functional Requirements for Bibliographic Records (FRBR)
A study by IFLA (International Federation of Library Associations) of the full range of functions performed by the bibliographic record– What do we use bibliographic records for?
Description, access, location, identification, annotations ...
The report provides a framework for the nature of and uses for bibliographic records
A conceptual model that can be used as a means to meet user needs and expectations
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Functional Requirements for Bibliographic Records (FRBR)
Tasks we use bibliographic records for:– Finding– Identifying– Selecting– Obtaining access to resources
FRBR should allow systems to handle bibliographic data in new, useful ways that fulfill these tasks
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Functional Requirements for Bibliographic Records (FRBR)
Conceptual model of relationships between bibliographic entities
Hierarchical relationships– Work
The intellectual product
– Expression An ‘expression’ of the parent work such as a translation,
edition, revisions, annotated text, etc. – Expressions entail additional intellectual effort
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Functional Requirements for Bibliographic Records (FRBR)
Hierarchical relationships– Manifestation
Published runs of each expression in multiple formats over time
The level at which we traditionally create a catalog record
– Item Each copy of a specific manifestation Circulation records track items
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Functional Requirements for Bibliographic Records (FRBR)
OCLC is researching the application of FRBR to WorldCat– “FRBRization”
They have created an algorithm that groups records automatically based on the Work/Expression/Manifestation/Item model
http://www.oclc.org/research/projects/frbr/algorithm.htm
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Identifiers
Four potential purposes– Locator
Where is the document I seek?
– Identifier Unique label for a resource
– Gatherers Groups like resources similar to a uniform title
– Differentiator Helps identify different versions of same resource
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Identifiers
Uniform Resource Identifiers (URI) – Generic set of all names/addresses that refer to
resources on the Web including: Uniform Resource Locator (URL) Persistent Uniform Resource Locator (PURL) Uniform Resource Name (URN)
OpenURL DOI ISTC
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Uniform Resource Locator (URL)
Web address or location at which a resource is held, not an identifier for the resource itself
Most common way to locate documents / items on the Web (http, ftp, mailto, etc.)
Not particularly stable or permanent– Error 404: File not Found
No metadata, but important starting point as we look at some of the related technologies
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Persistent Uniform Resource Locator (PURL)
PURL Service is managed by OCLC Functionally, a PURL is a URL The PURL remains constant even if the URL
changes - its function is to automatically re-direct a user to the current URL
PURL system/resolver is updated by resource manager to reflect any changes to location of the file, or URL
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PURLs
PURLs can be used both in documents and in cataloging systems
PURLs increase the probability of correct resolution and long-term access to resources
Use of PURLs can reduce the burden and expense of catalog maintenance (and business card printing)
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PURL - Example
US Government is a big user of PURLs– http://www.ccny.cuny.edu/library/Divisions/
Government/iraqbib.html
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Uniform Resource Name (URN)
Uniform Resource Names (URNs) are intended to serve as persistent, location-independent resource identifiers
Globally unique Never change Format
– urn:<namespace identifier>:<namespace specific string>
Use a resolver system to indicate current location of resource
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Digital Object Identifier (DOI)
Overseen by the International DOI Foundation DOIs are persistent, location-independent
identifiers of resources Developed to enable management of
copyrightable materials in an electronic environment (locate, buy, sell, track, license)
Specific type / implementation of a URN
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DOI
A two-part number with a prefix identifying the original publisher and a suffix identifying the specific work– Similar to the ISBN
A DOI resolution request for a specific resource would return one or more URLs - *locations* where a user could obtain access to the resource– Appropriate copy: online, text, free, illustrated, etc.
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DOI
Applications of the DOI will require metadata The basis of the DOI metadata scheme is a
minimal "kernel" of elements DOI minimal kernel elements of metadata:
– DOI, DOI genre, identifier, title, type, origination, primary agent, agent role, and administrative data such as registrant, and date of registration
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Questions?
Amy Benson
Program Director
NELINET Digital Services
NELINET, Inc.
508.597.1937
800.635.4638 x1937