My research and teaching interests focus on issues in geographic information science, including uncertainty in geographic information, discrete global grids, and volunteered geographic information. I directed or co-directed several large funded projects, including the National Center for Geographic Information and Analysis, the Alexandria Digital Library, and the Center for Spatially Integrated Social Science. I was elected member of the US National Academy of Sciences in 2002, and Foreign Member of the Royal Society and Corresponding Fellow of the British Academy in 2010; and in 2007 I received the Prix Vautrin Lud.

Research
I am interested in all aspects of geographic information systems, science, and technology. Accuracy and uncertainty are important issues in all of these areas, and involve the theoretical frameworks of fractals, geostatistics, and spatial statistics. I am interested in discrete global grids, a set of methods for representing variation over the curved surface of the Earth and implemented in tools such as Google Earth. I am interested in volunteered geographic information and in other paradigms for the production of geographic information. I am also interested in wayfinding and in urban mobility, including the long-term impacts of connected and autonomous vehicles.