Convex interface map is a diagram in which each convex space is represented by a circle and each building or bounded space in the system by a dot, and the dots are connected to the circles wherever there is a relation of both adjacency and direct permeability from the buildings or boundaries to the convex spaces.
Convex interface map
Sources
Hillier, B. & Hanson, J. (1984), The Social Logic of Space, Cambridge University Press: Cambridge. pp.104-5