Topological choice measures how many topological-depth-minimising paths between every pair of segments, exists under the definition of topological depth, that is, the topological depth along the lines between two adjacent segments.
Hillier, B. (2009),Spatial sustainability in cities: organic patterns and sustainable forms. In: Koch, D. and Marcus, L. and Steen, J., (eds.) Proceedings of the 7th International Space Syntax Symposium. (pp. p. 1). Royal Institute of Technology (KTH): Stockholm, Sweden. pp. k01.3-4.