ISSN 1039-3498 | no. 60 | December 2002
| National Library Maps Online The Digitised Map Collection |
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Abraham
Ortelius, 1527–1598
Americae sive novi orbis nova descriptio, cum privilego decennali. Ab. Ortelius delineasb. et excudeb. 1587 hand col map; 34 x 46.5 cm. on sheet 39.8 x 51.4 cm Map Collection RM 2099; nla.map-rm2099 |
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Following the launch of the Library of Congress rare map digitisation project in 1996, and a presentation at the National Library in 1997 by the former chief of its Geography and Map Division, Ralph Ehrenberg, the National Library of Australia began two trial projects to determine the feasibility of scanning its own rare map collections. The first project determined that direct scanning of originals with a digital (Scanback) camera, rather than scanning of surrogates (such as photographic transparencies) provided higher quality images. The second project established the technical requirements of such scanning, including the application of MrSID waveless compression technology to allow access to the fine detail inherent in most maps. In 2001 the National Library embarked on a major expansion of its digitisation program. The aim is to provide Library users with increased access to the special collections material through digitisation of pictures, maps, sheet music and manuscripts. Each type of collection material has different requirements for digitisation, as well as the management, storage and delivery of the digitised items over the Internet. The maps digitised to date are largely from the Rex Nan Kivell rare map collection. The maps to be scanned next will be drawn from the Ferguson and Tooley collections. These include maps of the world, the Pacific and Australia issued before 1900, including 16th- and 17th-century Dutch and French items which indicate the development of exploration, as well as early land settlement of the Sydney and Hunter Valley areas. Significant cartographers include Ortelius, Goos, Hondius, Coronelli and Sanson. The material consists of paper-based and linen-backed maps covering diverse subject areas such as town plans, geological maps, exploration and land tenure. While out of copyright, the rare and often very fragile nature of parts of the collection has meant that access to the maps has been restricted to either onsite use or through photographic copies. This has been slow and restrictive for most users. It is expected that digitisation will not only improve access for both Australian and overseas users but also increase awareness of the collection’s existence. It will also provide a high quality digital record of the material. Rare maps in the Library’s collection present particular digitisation challenges. The material is typically valuable, large format (up to 2 x 22 metres in size), fragile and difficult to handle. Maps also generally contain very fine detail, which needs to be captured effectively, and made available for viewing over the Internet to users. For map digitisation, the Library uses a PowerPhase FX scanner back-mounted on a Sinar large-format studio camera with 180mm Rodenstock lens. The system is installed on a high-precision, custom-built trolley, which moves backwards and forwards on specially laid tracks. With this device, it is possible to capture maps up to 100cm x 89cm in size (at 300 dpi resolution) producing 24-bit RGB TIFF, version six digital master files, up to 380 Mb in size. Larger maps need to be photographed in parts. For greater flexibility and to speed up the capturing process, the originals are positioned on a vertical vacuum board. Four high-intensity photographic tungsten lights are used to provide illumination strong enough to keep camera capture times to less than six minutes. The main software used is PhaseOne’s Image Capture and Adobe Photoshop, version six running on a Macintosh Powerbook laptop. Digitisation methods and standards were developed during the trial maps digitisation projects and further refined during the scanning process of the Nan Kivell rare map collection. In September 2002, the Library released the maps delivery system as part of its generic framework for access to digital collections. This system, located at: www.nla.gov.au/digicoll/, provides access to over 1000 maps. Users can identify maps by first searching the Library’s online catalogue www.nla.gov.au/catalogue/, and if the map is in digital form, by following a link to the maps delivery system provided through a highlighted URL address contained in the catalogue record. For example, the first published map of Port Jackson showing the eleven ships of the First Fleet and the buildings, tents, sawpits, workshops, storehouses and gardens of early Sydney is available. Simply search the map subset of the catalogue by doing a title keyword search for ‘Sydney Cove Port Jackson’. Several records should be returned. If you follow the ‘show details/more information’ link for the last record, which is the map by Francis Fowkes, there is a web link within the record to the maps delivery system. The persistent identifier for this map is: http://nla.gov.au/nla.map-nk276. Users of the maps delivery system can view low, medium and high-resolution images of maps along with descriptions of the items sourced from the Library’s catalogue. They can also link to an ‘interactive map’ which allows them to zoom in quickly to any selected area to examine fine details and then pan or zoom out to surrounding areas of the map. As users zoom in their current location is indicated on a small image of the whole map that can also be used to pan around the interactive map image. The size of the interactive map image can be changed to match the user’s screen resolution and the zoom level of the map is also displayed. The interactive map facility is provided using MrSID waveless image compression and Lizardtech Express Server technology. All map images are named using a persistent identifier, which is based on the rare map call number. These are used for both management of the digital map image and for citation and referencing purposes. Digitised maps are managed through the Library’s Digital Collections Manager database which provides the foundation for the maps delivery system, and are stored on its Digital Object Storage System. The
release of the digitised map collection represents a significant step
forward in the Library’s program to make its special collection materials
more accessible. With pictures, sheet music and now maps accessible via
the Internet, future work will concentrate on the Internet delivery of
manuscripts. |
| Contents list for this issue of Gateways |
Please address any comments and enquiries to The Editor, Gateways: gateways@nla.gov.au