Rare Maps Digitisation Project

Overview

For information on current developments please see: http://www.nla.gov.au/digicoll/

The Rare Maps Digitisation Pilot Project investigated the most effective means of creating high quality digital scans of rare maps and map series indexes from the Library's collection.

During the Project, 25 maps from the Rex Nan Kivell rare map collection were selected and captured at 300 dpi using a Phase One digital scanning back with a scanning resolution of 6,000 x 8,400 pixels and a 36 bit internal colour depth.

Seven maps were greater than 50.8 cm x 71.1 cm (20" x 28") and had to be captured through a number of image tiles. Image processing and stitching was carried out using Adobe Photoshop on a dual processor 500 MHz PC with 1 GB of RAM. Resulting master image files for the maps in TIFF format were between 100 and 600 MB in size. Five map series indexes relating to the ACT were also digitised during the project.

The master TIFF images were compressed using the MrSID software at a compression ratio of 22:1 for delivery over the Internet. A web site was created for the project with Catalogue records for each map, thumbnails and links to the MrSID versions which can be zoomed and panned to reveal map image details.

The technical recommendations of the project are:

  1. That the Library fund the digitisation of the Rex Nan Kivell rare map collection in the 2000/2001 financial year conforming to the technical procedures defined in this report.
  2. That digitisation of map material from the Library's collection be undertaken using a high-quality digital camera at a minimum of 300 dpi. That resolutions of 600 dpi be considered for highly detailed material on a case by case basis.
  3. That tiling and stitching of digital images of large format maps be avoided in digital imaging workflows through selection of a camera of sufficient resolution to capture entire maps in a single image.
  4. That master digital images of maps be stored for long-term preservation in uncompressed form on a network accessible RAID storage device and on CD in 24 bit RGB TIFF version 6.0 format.
  5. That MrSID software be used to compress map images for delivery over the web using a compression ratio of 22:1.
  6. That the Library develop an appropriate solution to the problem of loss of sheet identification detail (along the margins of the index) when zooming in on large format map series indexes.
  7. That to ensure correct handling and preservation of original materials, digitisation is undertaken in-house at the Library under supervision of Library collection managers.

See also the Paper presented by Maura O’Connor, Map Curator, National Library of Australia at the Australian Map Circle 27th Annual Conference, Brisbane, 5-8 April 1999

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