Analysis and Classification of Public Spaces Using Convex and Solid-Void Models

Urban planning and design are increasingly often supported by analytical models of urban space. We present a method of representation for analysis and classification of open urban spaces based on physical measures including three-dimensional data to overcome some observed limitations of two-dimensional methods. Beginning with “convex voids” constructed from 2D plan information and 3D data including topography and building facade heights, we proceed to “solid voids” constructed by aggregation of convex voids. We describe rules for construction of both convex voids and solid voids, including basic forms and their adjustment for perception. For analysis we develop descriptive characteristic values such as enclosure, openness, granularity and connectivity, derived from more basic geometric properties of the void representations. We also show how combinations of these values can be correlated with urban open space typologies, including commonly accepted traditional ones as well as previously unnamed classes of space. Concluding with discussion of some future planned developments in this work, we also propose that such methods can contribute to better understanding of the relations between urban forms and their perception and use, so as to guide urban transformations for improved urban quality.