This award in the Joint NSF/DARPA Initiative on Image Understanding and Speech Recognition is for an interdisciplinary study of computer vision in navigational reasoning. Computational and psychological approaches to spatial cognition will be combined to model expert map interpretation and perception of large-scale environments. The investigators will also develop representations and algorithms for navigational problem solving, with special attention to the role of vision in map-based navigation. Much of the work will be integrated with research projects by industrial collaborators.