Digital access to aerial and astronomical photographic archives (First phase : January 2002 - December 2003)

Description :

The aim of this project is to make the historic-scientific content of three photographic archives publicly accessible and scientifically usable by means of a high-resolution digitising technique. The historical aerial photographic collections of the National Geographical Institute (NGI-IGN) and the Royal Museum of Central Africa (KMMA-MRAC) along with the astrophotographic plate archive from the Royal Observatory of Belgium (KSB-ORB) - which represent an important part of the scientific heritage of these institutes - are all threatened in the sense that the information they contain may soon be lost for future generations. The reasons are: on one hand the ageing of the plate emulsion, on the other hand a lack of interest because the images are not readily accessible, nor are they available in digital form. The valuable and still actual information is therefore very difficult to process.

The NGI-IGN possesses a collection of some 50.000 aerial photographs systematically produced since 1947. This collection provides an objective image of our country at different epochs and was originally used to produce the institute’s famous ‘topographic maps’. The digitised scans will be useful for photogrammetric applications or for three-dimensional measurements. Today they are also perfectly suitable for historical research.

The KMMA-MRAC owns a large collection of aerial photographs of the Belgian Congo (more than 200.000 items) acquired between 1948 and 1959. This visual material was produced on a scale of 1/20.000 to 1/40.000 allowing to identify details as small as 2 to 4 m. It represents a unique and irreplaceable data set from which both the state of the natural environment and socio-economic information may be extracted for this period.

The KSB has a unique collection of almost 20.000 astrophotographic plates, the oldest of which date back to 1908. These glass plates cover a sky area of typically more than 1 square degree with epochs throughout the 20th century. They allow a 100 years old representation of the sky (and to search for unusual events such as supernovae) and long-term studies of astronomical phenomena (such as stellar proper motions, binary or variable stars with long periods, orbits of asteroids).

In the first phase we will produce digital and searchable inventories that will disclose the exact content and the state of each collection. These will allow us to identify the most valuable and most endangered parts of the collections. At the same time the physical conditions for the long-term storage of the plates and films will be improved - within the possibilities of each individual partner institute. Based on the results of the scanning of test plates (such as ‘geometric grids’ and ‘density scales’) we will select the most suitable scanner and most versatile scanning method. Our aim is to perform the scanning independently of future scientific applications, thus being useful for a broad range of disciplines. We plan to thoroughly test the technique of copy on film roll and high-resolution scanning. Consequently we will impose strict constraints on both the geometric precision and the radiometric transmission. The test phase will probably last over one year. A humidity/temperature-controlled room for the scanner is foreseen at the KSB-ORB. During this phase an international workshop on high-resolution digitisation will be held and a first concept for the data management, storage and post-processing (including data compression) will be developed.

In phase two we will start the operational scanning of and the electronic access to the digital images and the derived data. We will primarily scan the most valuable or most threatened subcollections, considering criteria linked with the quality, the degree of ageing and the scientific usefulness of the photographs. A definitive concept for the data management, data storage and the associated data bases will be made taking into account the rapid evolution of digital supports and data transmission. We will also perform a detailed estimation of the financial and human means required for the complete digitising of our collections and for providing access to the image data via the web for the public in general and for specialists in photogrammetry and in astronomy in particular.

- Contact person (project's coordinator):

Royal Observatory of Belgium (KSB-ORB)
Edwin Van Dessel
Av. Circulaire 3 / Ringlaan
1180 BRUXELLES / BRUSSEL
Tel : 02 373 53 66
Fax : 02 374 98 22
evdes@oma.be

PARTNERSHIP

Coordinator Royal Observatory of Belgium (KSB-ORB)

Partner 1 Institut Géographique National / Nationaal Geografisch Instituut (NGI-IGN)

Partner 2 Royal Museum for Central Africa (KMMA- MRAC)

Partner 3 Universiteit Antwerpen (UA) Onderzoeksgroep Astrofysica

Partner 4 Vrije Universiteit Brussel (VUB) Onderzoeksgroep Observationele Sterrenkunde (OBSS)

Partner 5 AGFA-GEVAERT nv