Average Radial (Qv) expresses the mean view length of all space visible from a location. In visibility graph terminology, it relates to the ‘through vision’ at a location (Turner, 2007). In isovist terminology, it represents the mean radial length at a location.

To determine Average Radial, the Isovist_App calculates the mean distance of successive radial-plan intersections from the radial origin for every point ‘V’ in plan. The outcome is an absolute value of length.

In notation form the calculation for Average Radial is expressed as: 

Where ‘Li’ is radial length and ‘n’ the total number of radials sampled.