Yukio Sadahiro / Professor / Division of Spatial Information Analysis
Department of Socio-Cultural Environmental Studies / / Spatial Information Analysis, GIS, Location Planning

Career Summary
1991 Assistant Professor, Department of Urban Engineering, University of Tokyo
1995 Lecturer, Department of Urban Engineering, University of Tokyo
1995 Lecturer, Research Center for Advanced Science and Technology, University of Tokyo
1998 Associate Professor, Center for Spatial Information Science, University of Tokyo
2001 Associate Professor, Department of Urban Engineering, University of Tokyo
2012 Professor, Center for Spatial Information Science, University of Tokyo

Educational Activities
Theory and Applications of GIS(Undergraduate, winter term)
Research Activities
1. Spatial Information Science for the Analysis of Human-Environment Systems

"Why is it that you white people developed so much cargo and brought it to New Guinea, but we black people had little cargo of our own?" This is a question asked by a native Guinean in "Guns, Germs, and Steel: The Fates of Human Societies" by Jared Diamond. Our life depends on natural, social, cultural, and economic environments, and they vary a great deal in both spatial and temporal dimensions. Diamond argues that the variation in human society has been shaped by geographical and environmental factors. His detailed and thorough discussion is based on his vast knowledge of geography, genetics, molecular biology, behavioral ecology, epidemiology, linguistics and archaeology.

Spatial information science gives us a more objective and quantitative perspective to answer the above question. How has the mountainous topography determined the form of Japanese cities? Is there any relationship between the climate and food culture? What happens when different cultures meet? Why is the retail structure so spatially complicated? Spatial information science is a very effective tool for answering these questions.

Our life also affects our surrounding environments. We form social, cultural, and linguistic environments and coexist with the natural environment. This is a human-environments system. Spatial information science gives us a means for revealing the underlying structure of the system and finding a desirable relationship between human beings and environments.

2. Spatial Information Science for Facility Location and Route Planning

Modern life, particularly urban life, requires facilities and infrastructures. Schools, fire and police stations, traffic networks, and administrative facilities need to be appropriately located, operated, and managed. Unfortunately, it is often quite difficult when working with limited economic and labor resources to find the optimal solution. This also applies to route planning, which covers a wide range of routes ranging from our daily commuting, shopping, and travelling to bus and tram networks and evacuation routes. It is quite a complicated task since it requires consideration of economic, physical, and mental costs.

Spatial information science is an effective means for solving such complicated problems. The optimal location and route as well as other desirable alternatives can be derived by implementing an interactive decision support system on GIS. Local governments have to find the most desirable location for a school in collaboration with residents and experts. Closure and integration of existing facilities are also critical in the era of population decline for efficient and practical urban environments. Interactive and flexible decision support systems need to be developed for facility location and route planning.

3. Spatial Information Science for Hobbies

Maps display territories of clans in the Edo period, old roads expanding from Edo, Japanese surnames, railway and bus routes, distributions of sake breweries and brewers, location of bending machines. Their maps attract us and raise a question: How were these spatial phenomena and distributions formed? Challenges to answer this simple but deceptively difficult question may seem not academic. However, they dramatically extend the applicability of spatial information science and have a great potential for provoking new spatial concepts and developing new analytical methods. The final goal is to construct a holistic framework of spatial analysis applicable to any spatial phenomenon.

1) Sadahiro, Y. (2013): A method for comparing numerical variables defined in a region, Computers, Environment and Urban Systems, to appear.
2) Sadahiro, Y., R. Lay, and T. Kobayashi (2013): Trajectories of moving objects on a network: Detection of similarities, visualization of relations, and classification of trajectories, Transactions in GIS, 17 (1), 18-40.
3) Sadahiro, Y. (2012): Exploratory analysis of polygons distributed with overlap, Geographical Analysis, 44 (4), 350-367.
4) Sadahiro, Y. and S. Sadahiro (2012): A decision support method for school relocation planning, International Journal of Urban Sciences, 16 (2), 125-141.
5) Sadahiro, Y. (2011): Analysis of the relations among spatial tessellations, Journal of Geographical Systems, 13 (4), 373-391.
6) Sadahiro, Y. (2010): Analysis of the spatial relations among point distributions on a discrete space, International Journal of Geographical Information Science, 24 (7), 997-1014.

Other Activities
Geographical Analysis (Editorial Board Member, 2003-present)
Transactions in GIS (Editorial Board Member, 2006-present)
International Journal of Society Systems Science (Editorial Board Member, 2010-present)
Future Plan
Our final goal is to establish a general framework of analyzing spatial information that can be used in a wide range of applications.

Messages to Students
Be intellectual. Liberal arts, interest, enthusiasm, and a positive attitude will all assist you in the cultivation of yourself.