Digital Libraries
In a Nutshell
Roy Tennant
The California Digital Library
Outline
The Vision
Definitions
Perspectives
Research
Production
Services
Collections
How to Keep Current
The Vision
Anyone, anywhere, will be able to easily locate and
use any image, text, database, or other type of digital
resource — often in sophisticated ways or in
association with other related objects
The only requirements:
access to the Internet
authorization or payment if required
Definitions: Part I
“electronic”
information stored and accessed by
electronic devices
“digital”
information stored and accessed by
computers (an electronic device)
“virtual”
in essence rather than in actual fact
Definitions: Part II
From the Association of Research Libraries http://sunsite.berkeley.edu/ARL/definition.html
Not a single entity
Requires technology to link the resources of many
Linkages are transparent to the user
Collections are not limited to document
surrogates, but include items that are exclusively
digital
Perspectives: Research
Research Perspective
Goal: to further knowledge
Participants: computer
science/library/information science faculty,
a few line librarians
Example:
U.S. Digital Library Initiatives (also called the
National Science Foundation DL projects)
Sample Research Issues
Advanced search techniques
e.g., query by image content
Federation of large, disparate,
and distant collections
Complex digital object behaviors
GIS overlays, moving image navigation,
etc.
Perspectives: Production
Production Perspective
Goal: to create digital library collections
and services
Participants: libraries (mainly larger
research libraries, but not exclusively)
Examples:
Library of Congress American Memory
(memory.loc.gov/)
eLib Programme (www.ukoln.ac.uk/services/elib/)
Digital Library Federation (www.clir.org/diglib/)
Production Issues
Services
Collections
Selecting
Acquiring
Organizing
Providing Access
Preserving
Services
The challenge: providing services when and
where they are needed
Examples:
Guides to Internet resources
Librarians’ Index - lii.org/
KidsClick! - kidsclick.org/
Network-based reference
Reference 24x7 247ref.org/
Selecting Digital Material
The process:
how do you discover what is available?
how can you evaluate the quality of resources?
how can cost effectiveness be determined? (books
remain, databases frequently don’t)
Considerations:
Purchase or license agreement
funding source
infrastructure required
staff time to mount and maintain
Selecting Material to Digitize
Focus on unique materials that are likely to
have broad interest
Build on strengths (seek critical mass)
Consider infrastructure required
Consider technical limitations
Acquiring: Digital Collections
The digital acquisition continuum:
linking
mirroring
hosting
archiving
LESS
MORE
Amount of Responsibility
New procedures and workflows are
required
tape loading, scanning, format translation, etc.
Acquiring: Non-Digital
Collections
Digitization methods:
scanner (flatbed, slide, handheld, etc.)
digital camera:
low-resolution - $US300-3,000+
high-resolution - $US25,000-35,000+
Kodak PhotoCD
Additional step for text
conversion
Optical Character Recognition
or Re-keying
Acquiring: Image File
Formats
Archival version: high-resolution TIFF
Online versions:
Preview: low-resolution GIF
Full: medium-resolution JPEG
High: med./high-resolution JPEG or TIFF
Up-and-coming: MrSID, Flashpix, PNG
Acquiring: Text File Formats
Original:
MS Word, Adobe
Pagemaker, etc.
Adobe Acrobat
Plain text
HTML
SGML or XML
Organizing: Naming and
Addressing
Object naming:
Objects should be named in a fashion that
promotes longevity (e.g., stay away from any kind
of implied meaning)
Object addressing:
URLs (www.w3.org)
DOI/Handles (www.cnri.reston.va.us)
PURLs (purl.org)
ARKs (www.ckm.ucsf.edu/people/jak/home/)
Organizing: Metadata
Structured description of an object or
collection of objects
Three basic types:
descriptive — e.g., title, creator, subject —
used for discovery
administrative — e.g., resolution, bit
depth — used for managing the collection
structural — e.g., table of contents page,
page 34, etc. — used for navigation
Organizing: Metadata
Appropriate standards or draft
standards:
Collection Level:
Encoded Archival Description (EAD) lcweb.loc.gov/ead/
Item Level:
MARC
Dublin Core - dublincore.org
METS - www.loc.gov/standards/mets/
Providing Access
How can we make our resources easily available to
a diversity of users with a multiplicity of purposes?
How can we integrate access to both print and
digital resources?
How can we
interoperate with
other digital
collections?
Preserving
Accepted preservation methods:
Acid-free paper
microfilm
photographic reproduction
The digital preservation strategy:
Storing
Refreshing
Migrating
The single most important aspect: institutional
commitment
Interoperability
The capability of two or more different digital
collections to be used as one in a transparent
fashion
One example:
Open Archives Initiative:
http://www.openarchives.org/
Requires standards (at minimum) or a
common platform
How to Keep Current
Electronic Discussions:
DIGLIB: www.ifla.org/II/lists/diglib.html
Web4Lib: sunsite.berkeley.edu/Web4Lib/
XML4Lib: sunsite.berkeley.edu/XML4Lib/
Publications:
“Digital Libraries” column in LJ —
libraryjournal.reviewsnews.com
D-Lib Magazine — www.dlib.org
Current Cites — sunsite.berkeley.edu/CurrentCites/
RLG DigiNews — www.rlg.org/preserv/diginews/