Abstract
Aiming at making clear the relation between the economical development in Shiga prefecture and the pollution of Biwa-Lake, we have developed a geographic information system REALS using personal computers. This paper describes the system architecture and the geographic data handling of REALS. In particular we will discuss in details the core database management system PIDMS for geographic data. The REALS is very useful to analyze the social data as well as economic data, and to present numerical results graphically by means of computer mapping. The setting up cost and running cost of REALS are so cheap that it is easy to introduce the system into even small scale administrations.
