Angular mean depth is the sum of the shortest angular paths over the sum of all angular intersections in the system. In DepthMap, it is defined as the sum of the shortest angular paths over the sum of the number of segments encountered on the paths from the root (origin) segment to all others.
Angular mean depth
Turner, A. (2001) Angular Analysis. In Proceedings of the 3rd International Symposium of Space Syntax, 1-13. pp. 4;
Turner, A. (2004), DepthMap4: A Researcher’s Handbook, UCL. pp. 28-29