Information Organization and Representation in Digital Libraries

1
Information Organization and Representation in
Digital Libraries
2
Outline

• Metadata definitions
• Typology of metadata
• Metadata standards
• Metadata encoding
• Metadata mapping

3
Why metadata?

• Information and knowledge organization and
  representation
• Resource description (cataloguing and indexing )
  and discovery (retrieval)
• Subject representation using knowledge
  organization systems

4
Metadata definition

• Metadata describes information resources such as
  websites , electronic texts , digital artifacts
  etc.
• The term is used both in singular and plural
  forms

5
Metadata definition

• Structured, encoded data that describe
  characteristics of information bearing entities
  to aid in the identification, discovery,
  assessment, and management of the desired
  entities.

American Library Association Committee on
Cataloging
6
Metadata scheme

• A metadata scheme provides a formal structure
  designed to identify the knowledge structure of a
  given discipline and to link that structure to
  the information of the discipline through the
  creation of an information system that will
  assist in the identification, discovery, and use
  of information within that discipline.

7
Typology of metadata

• Identification/Description metadata
• Administrative Metadata
• Terms and conditions Metadata
• Content ratings metadata
• Provenance metadata
• Linkage/relationship Metadata
• Structural metadata

8
Metadata standards

• Dublin Core
• GEM
• VRA Core
• MODS

9
Dublin Core metadata elements

• Title
• Creator
• Subject
• Description
• Publisher
• Contributor
• Resource type
• Date

• Format
• Resource identifier
• Source
• Language
• Relation
• Coverage
• Rights management

10
GEM (Gateway for Educational Materials)

• Based on Dublin Core with the addition of
  education-specific elements
• Additional elements Audience, Duration ,
  Essential Resources, Grade Level, Pedagogy,
  Quality Indicators, Academic Standards

11
VRA (Visual Resources Association)

• Consists of 17 categories
• Was modeled on Dublin Core
• Describe visual works of art and their surrogates
  or representations
• Additional Elements record type (work or image),
  measurements (dimension, format and
  resolution), material (substance), technique
  (production), style, culture

12
MODS (Metadata Object Description Schema)

• A hybrid metadata schema
• It provides an alternative between a simple
  metadata format (DC) and a very detailed format
  with structural complexities (MARC)
• It is richer than DC but simpler than MARC
• It has 20 top-level elements and 47 subelements

13
Top level elements
14
Metadata Application profile

• Is a set of metadata elements, policies, and
  guidelines defined for a particular application.
• An application profile is not complete without
  documentation that defines the policies and best
  practices appropriate to the application

15
Encoding standards

• Metadata can be recorded in a table or database
• It can be encoded in HTML (for simple metadata)
• It can be encoded in XML ( for highly structured
  and complex metadata)

16
METS (Metadata Encoding and Transmission
Standard)

• Developed by the Digital Library Federation (DLF)
  and is maintained by the Library of Congress
• A standard for encoding descriptive,
  administrative, and structural metadata about
  objects within a digital library

17
METS subsections

• A METS document can have up to seven major
  subsections
• 1. METS header (metsHdr)
• 2. Descriptive metadata section (dmSec)
• 3. Administrative metadata section (amdSec)
• 4. File section (fileSec)
• 5. Structure map (structMap)
• 6. Structural links (StructLink)
• 7. Behavior section (behaviorSec)

18
METS record
19
METS header

• ltmetsHdr CREATEDATE"2003-07-04T150000RECORDS
  TATUS"Completegt
• ltagent ROLE"CREATOR" TYPE"INDIVIDUAL"gt
• ltnamegtJerome McDonoughlt/namegt
• lt/agentgt
• ltagent ROLE"ARCHIVIST"
  TYPE"INDIVIDUAL"gt
• ltnamegtAnn Butlerlt/namegt
• lt/agentgt
• lt/metsHdrgt

20
Descriptive metadata (external)

• ltdmdSec ID"dmd001"gt     ltmdRef LOCTYPE"URN"
  MIMETYPE"application/xml" MDTYPE"EAD"    
  LABEL"Berol Collection Finding
  Aid"gturnx-nyufales1735lt/mdRefgt lt/dmdSecgt

21
Descriptive metadata (internal)

• ltdmdSec ID"dmd002"gt     ltmdWrap
  MIMETYPE"text/xml" MDTYPE"DC" LABEL"Dublin
  Core Metadata"gt         ltdctitlegtAlice's
  Adventures in Wonderlandlt/dctitlegt        
  ltdccreatorgtLewis Carrolllt/dccreatorgt        
  ltdcdategtbetween 1872 and 1890lt/dcdategt        
  ltdcpublishergtMcCloughlin Brotherslt/dcpublishergt
          ltdctypegttextlt/dctypegt     lt/mdWrapgt
  lt/dmdSecgt

22
Administrative metadata

• ltamdSec ID"AMD001"gt     ltmdWrap
  MIMETYPE"text/xml" MDTYPE"NISOIMG" LABEL"NISO
  Img. Data"gt    ltnisoMIMEtypegtimage/tifflt/nisoMI
  MEtypegt    ltnisoCompressiongtLZWlt/nisoCompressio
  ngt         ltnisoPhotometricInterpretationgt8lt/nis
  oPhotometricInterpretationgt        
  ltnisoOrientationgt1lt/nisoOrientationgt        
  ltnisoScanningAgencygtNYU Presslt/nisoScanningAgenc
  ygt    lt/mdWrapgt lt/amdSecgt

23
File group

• ltfileGrpgt     ltfileGrp ID"VERS1"gt
          ltfile ID"FILE001" MIMETYPE"application/
  xml" SIZE"257537"         CREATED"2001-06-10"gt
              ltFLocat LOCTYPE"URL"gt
                  http//dlib.nyu.edu/tamwag/beame.
  xml             lt/FLocatgt         lt/filegt    
  lt/fileGrpgt     ltfileGrp ID"VERS2"gt        
  ltfile ID"FILE002" MIMETYPE"audio/wav"
  SIZE"64232836"         CREATED"2001-05-17"
  GROUPID"AUDIO1"gt             ltFLocat
  LOCTYPE"URL"gt                
  http//dlib.nyu.edu/tamwag/beame.wav            
  lt/FLocatgt         lt/filegt     lt/fileGrpgt    
  ltfileGrp ID"VERS3" VERSDATE"2001-05-18"gt
          ltfile ID"FILE003" MIMETYPE"audio/mpeg"
  SIZE"8238866"         CREATED"2001-05-18"
  GROUPID"AUDIO1"gt             ltFLocat
  LOCTYPE"URL"gt                
  http//dlib.nyu.edu/tamwag/beame.mp3            
  lt/FLocatgt         lt/filegt     lt/fileGrpgt
  lt/fileGrpgt

24
Structural links

• ltdiv ID"P1" TYPE"page" LABEL"Page 1"gt
• ltfptr FILEID"HTMLF1"/gt
• ltdiv ID"IMG1" TYPE"image" LABEL"Image
  Hyperlink to Page 2"gt
• ltfptr FILEID"JPGF1"/gt
• lt/divgt
• ltdiv ID"P2" TYPE"page" LABEL"Page 2"gt
• ltfptr FILEID"HTMLF2"/gt
• lt/divgt

25
Metadata mapping

• Terms used mapping, crosswalks, interoperability
  
• A specification for mapping one metadata standard
  to another
• A key difficulty is the element-mapping process
• It is easy if the schemes are simple, of the same
  discipline or for the same type of materials
• It is challenging if it is cross-domain, or the
  mapping is between two schemes with great
  semantic differences or different levels of
  complexity

26
Dublin Core - MARC crosswalk
27
AlouetteCanada

• One navigation and resource discovery system to
  find digital collections from libraries,
  archives, galleries, museums, historical
  societies in a wide range of formats
• Will aggregate current digitized content
• Metadata toolkit
• Alouette Canada http//alouette.ourontario.ca/sea
  rch