Axial choice is the measure of choice calculated within an axial map. It measures how often an axial line lies on the shortest topological paths (turnings) between any pair of axial lines.
Hillier, B., Burdett, R., Peponis, J., Penn, A. (1987), Creating Life: Or, Does Architecture Determine Anything? Architecture et Comportement/Architecture and Behaviour , 3 (3) 233 – 250. pp. 237