Building Long-range Cognitive Maps using Local Landmarks

Cognitive maps can be built using only information about the relative positions of locally visible landmarks. We describe a system that can compute paths between any two locations, irrespective of whether they share common visible landmarks, without using 'compass' senses or dead reckoning abilities. This is achieved by encoding the position of each landmark in the barycentric co-ordinate frames defined by groups of neighbouring cues. Paths between distant points are computed by calculating, using these frames, the positions relative to the agent of landmarks further and further away from the immediate scene. Once the relative positions of landmarks local to the goal are known a vector giving its position in the agent's egocentric frame can be found. This implicit map allows the agent to compute the overall distance and direction to distant targets; find and follow paths to goal locations; generate explicitly the layout of the whole environment relative to its own position; and discriminate between perceptually similar landmarks. The system is robust to noise, its calculations require only linear mathematics, and its memory requirements are proportional to the total number of landmarks.