A Development of 3d Urban Information System on Web

The needs for 3D city models are growing rapidly and the applications of those models on computer graphics and virtual reality are appearing in a variety of fields in recent years. In parallel, the speed of the internet communication is being greatly improved by the fast and wide spread of broadband infrastructure. Today, those web3D applications are waited eagerly that make possible interactive fly-through and walk-through manipulations in detailed 3D city models on the internet. For the recent few years the authors have developed techniques for automatic generation of 3D city model using LIDAR data, 2D digital map and aerial photography, as well as a virtual reality (VR) viewer software with high-speed graphic engine which can deal with large areas of 3D city models on VR. The newly developed 3D urban information system on web can provide transmission and reception of a great amount of urban information with interactive manipulation of detailed 3D city models linked with geographic information system (GIS), on ordinary internet infrastructure such as DSL. New techniques have been developed for the system, including; (a) reduction of data, (b) level of detail (LOD) and streaming, and (c) linkage between 3D city model and geographic information system (GIS). Based on those techniques the authors have developed a prototype system that includes the design and construction of a client-server system as well as the development of the client software. After those basic developments the authors conducted an experiment of communication in a local area network (LAN) environment, which resulted in a great success.