GEO-REFERENCED IMAGE-BASED SYSTEMS FOR URBAN INFORMATION MANAGEMENT

The use of aerial photographs in the UK has increased significantly si nce the mid 1980s. At the same time, the growth in Geographical Inform ation Systems (GIS) has promoted the need for the broader use of digit al aerial photographs that can be integrated with map-based data. Digi tal photogrammetric solutions remain expensive and require a high leve l of training to use. Consequently, the Geographic Data Archiving Syst em (GEO-DAS) project set out to create an image-management system that provides the photo interpreter with a digital equivalent to the tradi tional paper print and film overlay. The objective was to give the use r a large geographical coverage in the form of partially corrected, ge o-referenced images, forming a seamless database that could be stored on a low-cost computer platform, but yet generating a high-quality ima ge. The potential for using digital aerial photographs as a basic sour ce of spatial data within the built-up environment is enormous, partic ularly where they are also part of an integrated suite of software tha t could include GIS, mapping, databases, and word processing or deskto p publishing, run in a multi-tasking environment. However the aerial p hotograph provides only part of the information necessary to create a complete understanding of an urban area Other types of data, including multimedia data, must be taken into consideration. This raises questi ons about the purpose to which urban information systems are to be emp loyed, and how the various datasets are to be structured in order to a chieve a widely applicable information resource. A second project has commenced using GEO-DAS as the spatial kernel to a more comprehensive urban information system.