Staff Papers

Building a Digital Library at the NLA

A presentation given by Tony Boston, Director, Digital Services, National Library of Australia at the OZeCulture 2002: taking the next step conference held 28-30 May 2002 in Sydney Australia. Slides associated with this presentation are being posted on the OZeCulture 2002 web site1.


Introduction

Today I'm going to be talking about building a digital library at the National Library of Australia. I will talk about the components of the digital library and the functions it supports illustrated with some online examples.

The aim of the Digital Services Project is to develop a systems infrastructure which enables the Library to manage its digital collections, both digitised copies of collection items and born-digital electronic publications or web sites captured for long-term archiving.

The digital library that is being developed must support the collection, storage, management, discovery, access, web delivery and long-term preservation of this material. These are traditional library functions that are no different in the digital age.

Digitisation program

In 2001 the Library embarked on a major digitisation program2 for pictures, maps, manuscripts, and sheet music from its collection. The material being digitised is a unique part of Australia's cultural heritage and includes beautiful photos by photographers such as Cazneaux, Dupain and Hurley, rare historical maps, early Australian sheet music and manuscript material such as letters, diaries and objects (for example, here is a gold medallion given to Edmund Barton by the pope in Rome in 19023).

For the 2001/2002 financial year, the targets for digitisation are 20,000 pictures, including 10,000 photos by Frank Hurley and several thousand cartoons by Geoff Pryor, one thousand maps from the Rex Nan Kivell rare map collection, 3,500 pieces of pre 1930 Australian sheet music and various manuscript collections including the papers of Edmund Barton and Joseph Banks.

Digital master images are held in high resolution uncompressed 24 bit RGB TIFF version 6 format while low resolution derivatives for viewing on the web are held in 72 ppi JPEG format.

Online access

Once the material is collected and stored, online access is possible through services such as PictureAustralia4 which provides access to over half a million Australian cultural heritage images from libraries, museums, archives and galleries. And through services like the Library's own Pictures Catalogue5 which provides access to images of items from the Pictorial Collection, and special delivery systems and online exhibitions such as those for the diary of William Wills6 in association with a current exhibition about Bourke and Wills and the papers of Sir Edmund Barton7, our first Prime Minister.

Storage infrastructure

In June 2001, the Library purchased a server and tape library8 to store digital material. Current capacity is 2 terabytes of disk with a 4 terabyte tape library. Needless to say, after nearly one year of operation, this space is already full! This is not surprising when you consider that the average sound digital master is greater than 1 gigabyte and image masters can be over 500 megabytes in size. Next financial year this will be expanded to 3 terabytes of disk and 12 terabytes of tape storage. A structured filesystem has been developed to store images and sound files, digital master files are stored on tape and derivatives for viewing on the web are stored on disk. Files on tape appear to the user to be online (they are actually nearline) and are automatically fetched in a few minutes from tape when requested by a user.

Digital collections management

Once you have digitised, collected and stored your material, the next step is to effectively manage it. The Library is developing in-house an application called the Digital Collections Manager to support the digitisation process, creation of web derivatives, storage of technical metadata and digital files.

The Digital Collections Manager allows storage of management and technical information about collection items, currently supports management of images, and soon will support management of audio recordings from the Oral History Collection. In the future it will be enhanced to support recording of rights management information and information used for preservation management.

The metadata stored in DCM includes:

  1. Descriptive metadata sourced from the Library's Catalogue
  2. Technical metadata, for example image format, resolution, dimensions, audio bit and sample rates etc
  3. Structural metadata describing the files that make up a digital object and their relationships

Persistent identifiers

Once you can collect, store and manage digital objects, you need to consider their location for access. The Library has adopted a scheme for assigning a unique and persistent identifier9 for every digital object. Schemes are, where possible, based on existing naming schemes for physical items. A resolver service has been developed that redirects a user to the current location of an object based on its persistent identifier. This solves the error that commonly occurs on the web when a resource is moved, as they inevitably will be, when new technologies for delivery are introduced. With the Library's resolver service, if a digital object is moved then, just a simple change to a configuration file is needed to ensure continued access to that resource.

Persistent identifier web addresses have two components - the resolver which is a web server at the National Library, and the persistent identifier. They are of the form:

http://nla.gov.au/<pi>

For example: http://nla.gov.au/nla.ms-ms51 for the Papers of Edmund Barton.

These are logical addresses which remain the same while the physical location can change. To use a Library analogy, this is a little like the Dewey classification number for the copy of a book, which remains the same even though its shelf location can change over time. What we have done at the Library is to solve this problem for our own digital collections. What is really needed is a global Internet-based system that supports persistent naming and resolution but this is not likely in the near future.

The Library harvested the Sydney 2000 web site every day during the 2000 Olympic Games and http://nla.gov.au/nla.arc-10194 is the persistent web address for the games site in the Library's PANDORA archive. It is interesting to note that the Atlanta Olympic Games web site no longer exists anywhere in the world and we should consider if we are currently living through the digital dark ages or a digital golden age. We know very well how to preserve a book for hundreds of years but in an environment of rapid changes in hardware, software and digital file formats how do we preserve and continue to provide access to digital material in the long-term?

Access and delivery

Once you have collected, stored, managed, and identified your digital collections, you can provide online access to them. The Library is developing web delivery systems based on the Digital Collections Manager database. These systems provide access to a digital object with context provided using descriptive metadata, with page turning, transcripts, and search or browse options. Persistent Identifier web addresses are used to link from external discovery systems such as the Library's Catalogue or PictureAustralia to the web delivery systems. I'll now look at several examples of web delivery systems that have been developed at the Library.

Papers of Edmund Barton

Last year the Library developed a site providing access to the Papers of Edmund Barton. 5,400 images of over 2,000 letters, diaries, speeches, political papers, photos and objects are accessible online. The web site is based on a finding aid which organises the collection into 13 series. Users can search or browse using the finding aid, and zoom in and navigate within items.

All of the static web pages for this site are automatically generated using XSL style sheets from a finding aid encoded in XML Encoded Archival Description (EAD) format. A PDF version of the finding aid is also available generated from the EAD using XSL formatting objects. You can browse and search the thirteen series online, and you can print a PDF version of the finding aid.

When you examine an item from the Barton papers, you can see each page in detail, and turn pages for multi-page items. Each item has a citation at the bottom and a persistent identifier web address for referencing that page.

Pictures Catalogue

The Pictures Catalogue provides access to over 65,000 Catalogue records and 40,000 online images of items from the Library's pictorial collection. It supports image collections, online ordering and digitisation on demand. Future versions of this service will support online image purchasing and e-commerce.

Sound and sheet music

A new and exciting project at the Library is MusicAustralia which, through collaboration with other agencies, aims to make Australian music resources more easily accessible. The initial phase of the project is a pilot with ScreenSound Australia which will deliver online access to sheet music from the National Library and associated recorded performances from ScreenSound Australia. The Australian Music Centre and Australia Council are also participating in the pilot. The project is also looking at technical issues relating to the synchronization of recorded sound with sheet music images. Results are expected by the end of 2002.

Systems architecture

In conclusion, a framework for collection, storage, management and access to digital collections is being created at the National Library through development of a publicly accessible digital library.

This diagram shows a simplified systems architecture for the digital library. From the bottom there is storage and management of digital collections and from the top or user's point of view we can search the Library's Catalogue or collaborative services such as PictureAustralia or MusicAustralia, view metadata about an item and then, if it has been digitised or is in digital form, navigate via a persistent identifier web address to the actual digital object accessible via a web delivery system.

1

Simplified systems architecture for the digital library

Footnotes

1 OzeCulture 2002 - http://www.cultureandrecreation.gov.au/conference/

2 Digitisation of traditional format library materials - http://www.nla.gov.au/digital/program.html

3 Papers of Edmund Barton, Series 13: Objects, Item 1296: Gold medallion presented to Barton by Pope Leo XIII in 1902, Part 2 - http://nla.gov.au/nla.ms-ms51-13-1296-s2

4 PictureAustralia – http://www.pictureaustralia.org

5 Pictures Catalogue – http://www.nla.gov.au/catalogue/pictures/

6 The Diary of William John Wills - http://www.nla.gov.au/epubs/wills/

7 Papers of Sir Edmund Barton - http://nla.gov.au/nla.ms-ms51

8 Digital Object Storage System - http://www.nla.gov.au/dsp/doss/doss.doc

9 Persistent identifier scheme adopted by the National Library of Australia - http://www.nla.gov.au/initiatives/nlapi.html

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