Space Syntax Approaches in Architecture

Introduction

The canonical works of Space Syntax are The Social Logic of Space (Hillier & Hanson, 1984), Space is the Machine (Hillier, 1996) and Decoding Houses and Homes (Hanson, 1998). Collectively these three define the primary conceptual framework of the theory. In the first of these, Hillier and Hanson (1984) argue that spatial organisation has social consequences, and present a range of techniques for analysing the two-dimensional spatial properties of built environments. In these techniques, the syntactic properties of an architectural or urban plan are abstracted, using various protocols, into a set of nodes and edges in a graph. Once converted in this way, the graph can be mathematically analysed, and the results are mapped back to the properties of the plan it was derived from. In this way, Space Syntax approaches are used to reveal the relationships between spaces and the social properties that necessitate or sustain these relationships (Hillier & Hanson, 1984).

Three basic correlations or mappings between human activities and spatial geometry are central to the majority of the Space Syntax techniques (Hillier & Vaughan, 2007). First, the movement of people through space can be conceptualised in terms of vectors or directions, leading to the proposition that “people move in lines”. Second, people inhabit and interact in visually defined spaces, which, in geometric terms, are known as convex spaces. A convex space is one in which a straight line connecting any two points in the space does not cross a wall. Or, more intuitively, a convex room is one wherein, regardless of where you stand, the entire room is visible. Third, people understand the world, and find their way through it, using visual fields which change relative to the properties of the location they are in. These three correlations could be regarded as being between aspects of spatial topology and human behavioural, social and cognitive patterns, respectively (Figure 1).

The first of these three correlations or mappings is undertaken in Space Syntax using alpha analysis (employing an axial line map), the second, gamma analysis (using a convex space map), and the third uses isovists (or isovist fields). The first two of these, which rely on graph theory, are introduced in The Social Logic of Space, which also provides techniques for measuring and comparing the properties of graphs, including the extent to which nodes are integrated or segregated. Axial line analysis is ideally suited to studying street configurations in urban settlements, as streets could be regarded as primarily serving as spaces of movement. Convex space analysis is commonly used for studying the interior spatial configuration of buildings, as these are among the most important sites of social interaction and inhabitation. Hillier and Hanson (1984; Hanson, 1998), also introduce the concept of a building genotype, which can be uncovered using a “justified permeability map”. This type of graph, which has had several different names over time, is called a justified plan graph (JPG) in the present book. The third approach, visibility analysis using isovists, was initially presented as an adjunct to convex and axial analysis, however, over time it has developed into an important technique in its own right. In particular, a considerable body of evidence has been developed demonstrating potential correlations between the mathematical properties of isovists and human spatial perceptions and responses (Stamps, 2005a, 2005b; Turner, Doxa, O'Sullivan, & Penn, 2001). The origins of isovist analysis are now more commonly traced to the work of Tandy (1967), whereas the Space Syntax technique known as visibility graph analysis (VGA) merges aspects of both isovist geometry and graph theory.

Figure 1.

Three Space Syntax techniques that capture “intrinsic aspects of everything human beings do”, adapted from (Hillier & Vaughan, 2007)