VISUALIZATION AND INTERACTION TOOLS FOR AERIAL PHOTOGRAPH MOSAICS

This paper describes the development of a digital spatial library base d on mosaics of digital orthophotos, called Interactive Portugal, that will enable users both to retrieve geospatial information existing in the Portuguese National System for Geographic Information World Wide Web server, and to develop local databases connected to the main syste m. A set of navigation, interaction, and visualization tools are propo sed and discussed. They include sketching, dynamic sketching, and navi gation capabilities over the digital orthophotos mosaics. Main applica tions of this digital spatial library are pointed out and discussed, n amely for education, professional, and tourism markets. Future develop ments are considered. These developments are related to user reactions , technological advancements, and projects that also aim at delivering and exploring digital imagery on the World Wide Web. Future capabilit ies for site selection and change detection are also considered. (C) 1 997 Elsevier Science Ltd.