Route Choice from Local Information: Comparing Theories of Movement and Intelligibility

Intelligibility, the extent to which non-local structure can be inferred from local properties, is examined using new methods based on angular segment analysis, demonstrating that such a property is consistent with exosomatic navigation. In many urban networks, effective movement is possible without knowledge of the broader structure, or memory, using information conveyed to a navigator only by the angles of each intersection. Results suggest that this is not due to a particular optimisation of the grid unique to cities, as has been suggested, but can result in many possible networks, including random ones. A relationship between intelligibility and predictability of movement, implied in previous literature, is shown not always to hold. Additional methodological and theoretical contributions are made in proposing a novel measure of immediate angular intelligibility, and in demonstrating equivalences between this and traditional axial line intelligibility, and between a number of other methods proposed to predict movement in the literature