An Application for Isovist Field and Path Analysis

This paper briefly describes the software application OmniVista written for the Apple Macintosh Platform. OmniVista is essentially an isovist generating application, which uses the 2d plan of a building or urban environment as input data, and then can be used in one of three modal ways. Firstly, point isovists can be generated by ‘clicking’ onto any location in the environment. Secondly, all navigable space can be flood-filled with points, which may then be used to generate a field of isovists. Finally, a path of points can be used to examine how isovist properties vary along the path the results of this can either be output as numerical data, or exported as a series of pictures, which may be combined to form an animation of the varying isovists along the route. This paper will examine all three modes of use in turn, starting from the simplest (point) to the more complex (the path). A description and equation for all isovist measures used in the application will also be given as an appendix to the paper. OmniVista1 was first developed in February 1999 and completed by mid March 1999, it is not, therefore, a new piece of software. It is based on the concept of the isovist, most widely associated with Benedikt (Benedikt 1979; Benedikt and Burnham 1985). Since this paper is a software paper, we will assume that the reader is familiar with the concept of an isovist, suffice to say it is a 2d polygonal representation of visible space as generated from a single vantage point. OmniVista is a privately written piece of software with no institutional affiliations. OmniVista’s functionality may usefully be held to divide into three possible ‘modes’. The first mode is that of generating a single point isovist. This is used to examine the properties of the field of view from a single, or number of distinct, locations. The second mode in which OmniVista may be used is to flood-fill all navigable space with a grid of vantage points and to generate an isovist at each of these locations. The final and third mode in which the application may be used is to generate isovists along a path. Each of these three modes will be presented in this paper, along with an appendix containing definitions of the measurements used by OmniVista. OmniVista An Application for Isovist Field and Path Analysis Ruth Conroy Dalton University College, London UK Nick Dalton Architectural Association, London UK