A spherical metric for the field-oriented analysis of complex urban open spaces

The author deals with the analysis of urban open spaces, once conceived as part and parcel of our urban heritage. He introduces a mathematical modelling technique that is capable of mapping the variation of the sky visible from points distributed throughout space. The resulting maps overcome the limits of orthographic (plan, section, and elevation) and perspective methods of analysis by considering the dynamic qualities of the Gibsonian 'visual world' that takes account not only of bifocal vision but also of the relatively free movement of the head and shoulders, that is, vision as part of the human ecology. The maps show how a person might experience those volumes of a void that define a space, not from a fixed point but from moving about inside the entire urban open space.