Okabe, Atsuyuki (1945–)

Atsuyuki Okabe received his PhD from the University of Pennsylvania in 1975 and a doctor of engineering degree from the University of Tokyo in 1977. He was the director of the university's Center for Spatial Information Science (CSIS) from 1998 to 2005. He is currently a professor at the University of Tokyo and a member of the Science Council of Japan.

Okabe was one of the first to apply Voronoi diagrams to the spatial competition problem (Hotelling problem) and showed that the equilibrium states in a two-dimensional (2D) space were drastically different from those in a 1D space. Since then, he has extensively studied Voronoi diagrams, and his outcomes were developed into a book, Encyclopedia of Voronoi Diagrams, which provides a general framework for studying Voronoi diagrams and illustrates hundreds of applications in various fields. It has been cited in more than 1,700 articles.

He also broadened the applications of geographic information systems (GIS) to the humanities and social sciences. One book pioneered the systematic applications of GIS to Islamic studies, which was well received and earned him the World Prize of the Book of the Year of the Islamic Republic of Iran. Another book developed the frontiers of the applications of GIS to the humanities and social sciences.

He developed new spatial analysis, namely, spatial analysis on networks. Traditional spatial analysis assumes that space is given by a plane with Euclidean distance. Okabe proposed a new paradigm, where space is represented by networks embedded in the 2D or 3D space with the shortest-path distance. In addition, he and his colleagues developed a toolbox for spatial analysis on networks called SANET. SANET is now used by researchers in more than 40 countries.

Furthermore, he published a series of articles on city systems. Okabe theoretically analyzed the relationship between the optimal city-size distribution and Zipf's rank-size rule. He developed an integrated theory that combines a macro-empirical law, the rank-size rule, and a micro-empirical law, the Clark's law of urban population distribution. Okabe and colleague Sadahiro demonstrated why Christaller's city system could be observed in the real world using spatial random point processes.

He has contributed tremendously to the development of research in spatial analysis and geographic information science. In short, he is the founder of these fields in Japan, both in research activity and in terms of organizing a research organization, namely, CSIS in the University of Tokyo.