With the trend of “down-sizing”, philosophy and concept of computer-assissted environmental information systems are subject to drastic changes. Personal computers (PCs) have come to be more effectively used for processing large volume data than before; they can even match engineering work stations in terms of calculation speed and memory capacity. Moreover, PCs provide users with more freedom and flexibility of establishing user-oriented data handling and analysis systems. This paper presents an example of environmental information system based on the most modern PCs and an object-oriented programming language (VBA; Visual Basic for Applicaion). It demonstrates how non-professional users with relevant computer knowledge can develop geographical information system and other data processing systems.