After nearly 25 years of teaching planning and geography, he moved to direct the NSF National Centre for Geographic Information and Analysis (NCGIA) at the State University of New York at Buffalo (SUNY-Buffalo). He also has held several visiting appointments in computing, engineering, planning, and geography at the Universities of Illinois, Melbourne, Hong Kong, Bristol, and Michigan, and is currently a Visiting Distinguished Professor at Arizona State University, and an Honorary Professor at Cardiff University.