Area (Av) expresses the area of all space visible from a subject point in the plan (Benedikt, 1979). In visibility graph terminology, it represents the number of other subject points that said location is directly ‘connected’ to, called ‘Connectivity’ (Turner, 2001b). Isovist_App Area has been shown to correlate to DepthMap’s Connectivity.
To determine Area at point ‘V’, the Isovist_App simply extracts the geometric area value from the polygon of the isovist calculated at V. The outcome is an absolute value in units.
In notation form the calculation for Area is expressed as:
Where xi, yi is the vector from V to each vertex of the isovist polygon, and n the total number of vertexes of the isovist.