Vista Length (Hv) expresses the longest single view available at each location. In isovist terminology, it records the longest radial of the isovist at a location. Vista Length values identify regions of high axial view.

To determine Vista Length at point ‘V’, the Isovist_App calculates the distances between each vertex of the polygon of the isovist, and the origin point of the isovist calculated at V. The highest distance is recorded. The outcome is an absolute value of length.

In notation form the calculation for Vista Length is expressed as: 

Where ‘Li’ is the length from each isovist vertex point to point V.