Australia has recently released a new Web service for the discovery of its cultural heritage in pictures. The service, called PictureAustralia, was built using a combination of standard metadata, Z39.50 and XML. However, the most significant building block has been collaboration.
An Application of the Dublin Core
An Australian collaboration of libraries, museums, archives, and galleries is revealing the wealth of the nation's unique pictorial collections. Using simple Web technologies, the State Library of New South Wales, State Library of Tasmania, State Library of Victoria, Australian War Memorial, National Library of Australia, National Archives of Australia, and Fryer Library of the University of Queensland have provided a single entry point to their digitised images of art, photographs, and artifacts.
This single entry point is called PictureAustralia. It allows images to be found without knowing in advance which institution manages them. The service is provided free of charge to all with an interest in Australia, its culture, its history, and its people.
An Application of the Dublin Core
The PictureAustralia service has been assembled through the application of the Dublin Core metadata schema. Each image provider has mapped its original image descriptions resident on its Web site to the Dublin Core. The descriptions may be sourced from MARC21 or an internal schema. The choice of the Dublin Core was a participatory decision, to ensure that resource discovery was consistently enabled across the disparate collections.
Despite the optionality of the Dublin Core elements, searching is reasonably consistent across the collections. A few of the elements are highly recommended to ensure expected search behaviour - a title (which labels the image even where that image traditionally did not have one, such as a photograph), source (essential for identifying the individual image provider), and a rights management statement (at the item or collection level).
The subject or topic of each image is not always provided. However, any thesaurus term already provided is accepted into the service. These may be sourced from Library of Congress Subject Headings, military-specific headings, or other in-house thesauri. PictureAustralia recommends the use of a newly developed thesaurus, the Australian Pictorial Thesaurus which is based on the PICMAN thesaurus of the State Library of New South Wales. Its focus is on the use of Australian terms for pictorial and manuscript items.
PictureAustralia is broad in scope. Any image of Australia or created by an Australian may be included. People, places, and events in history are depicted from Australia's earliest days to the present time. The only exclusions are text, unless it forms part of an artifact and the artifact is digitised; maps and manuscripts, (although photographs of maps may be included); and whole video or audio clips, (but a frame of a video that is presented as a picture may be included).
PictureAustralia plans to explore ways of integrating audio and video in the future. It is worth noting that the service carefully considered interface design which could be reasonably accessible to Australians in rural and remote areas, and adhered to ubiquitous design principles not requiring special software to view the images. The user interface was graphically designed outside the library environment. This was a deliberate decision, to avoid the nuances and knowledge of bibliographic system design.
To provide functionality for people without experience using advanced search systems, the trails access point was introduced. Trails attempt to create a visual link between materials based upon a theme. Metadata is analysed and stored as a pre-set search, one for each trail. The results are not stored. This allows new images matching the metadata to be incorporated monthly to enhance each trail.
The architecture is hybrid in nature - the images in their 'thumbnail' sizes are not held centrally, rather, they are stored at each of the participating sites. Each of the sites also holds larger-sized images. The metadata is held in a central repository at the National Library of Australia, stored in XML (eXtensible Mark-up Language) format. The search and retrieve protocol, Z39.50 (ISO 23950), is used as the query protocol during searching, and it supports Boolean operators and right-handed truncation. The metadata is harvested on a regular basis, in full, with the use of the Blue Angel technologies' MetaStar Enterprise product. It is subsequently indexed for searching via the central interface.
While Z39.50 also supports relevance ranking, this activity is not deployed for the search results. The different creation practices within the original metadata schemas mitigate against the precision that relevance ranking imposes. For example, the provision of additional subject terms to support search broadening techniques results in unfair weighting of those collections in the search results. The presence of the Z39.50 capability also means that it would be possible to provide the service with distributed repositories of metadata. To date, however, PictureAustralia has found it to be more efficient to provide centralised access, in terms of both cost and search response times.
The most striking success factor of PictureAustralia has been collaboration across the Australian cultural sector. This has been partly due to its unobtrusive nature. It does not require a great deal of resource to achieve interoperability where Web collections of images already exist. The deliberate duplication of metadata has allowed separate single-institution gateway services to operate without impediment. Not only does PictureAustralia bring attention to individual collections, it allows Australians in rural and remote Australia to access the wealth of collections held in the capital and regional cities. It meets the commitment of those agencies to bring their collections closer to all Australians.
PictureAustralia is available for viewing at www.pictureaustralia.org. It recently won the Australian Financial Review's Australian Internet Awards 2000 in the Arts category, because it is an "excellent portal for Australian cultural material of a pictorial nature", it "seamlessly integrates multiple multimedia databases into an elegant visual experience for the customer", and its "use of metadata is excellent". The ongoing collaboration and commitment of the participating agencies made this possible.
About the Author
Debbie Campbell is Director of Infrastructure Projects, Coordination Support Branch, at the National Library of Australia in Canberra.
Paper received 18 December 2000; accepted 31 December 2000.
Copyright ©2001, First Monday
Picture That: Australia in the forefront by Debbie Campbell
First Monday, Volume 6, Number 1 - 8 January 2001