Knowledge about a particular environment is represented in terms of route descriptions, a topological network of paths and places, multiple frames of reference for relative positions, dividing boundaries, and a structure of containing regions. The current position is described by the ``You Are Here'' pointer, which acts as a working memory and a focus of attention. Operations on the cognitive map are performed by inference rules which act to transfer information among different descriptions and the ``You Are Here'' pointer. The TOUR model shows how the particular descriptions chosen to represent spatial knowledge support assimilation of new information from local observations into the cognitive map, and how the cognitive map solves route-finding and relative-position problems.
A central theme of this research is that the states of partial knowledge supported by a representation are responsible for its ability to function with limited information or computational resources. The representations in the TOUR model provide a rich collection of states of partial knowledge, and therefore exhibit flexible, ``common-sense'' behavior.