This book constitutes the refereed proceedings of the 5th International Conference on Geographic Information Science, GIScience 2008, held in Park City, UT, USA, in September 2008. The 24 revised full papers presented were carefully reviewed and selected from 77 submissions. Among the traditional topics addressed are spatial relations, geographic dynamics, and spatial data types. A significant number of papers deal with navigation networks, location-based services, and spatial information query and retrieval. Geo-sensors, mobile computing, and Web mapping rank among the important new directions.