Unpacking isovists: a framework for 3D spatial visibility analysis

This article explores the ways in which researchers conceptualize and visualize visibility in spatial research – using isovists and visualscapes. We review how visibility analyses have been used in spatial analysis and visualization. We dissect the geometric conceptualization of isovists, and geometric relationships between isovist origins and targets. From this, we develop an expanded typology of isovists based on geometries of visibility and the relationships between an observer and the observed. This typology differentiates panoptic isovists, constrained isovists, and targeted isovists. We apply these isovist examples to urban privacy and surveillance to ground the new conceptual framework. We conclude with a discussion surrounding future research and conceptual development needed to advance visualscapes and visibility analysis.