Space Syntax: Urban Network & Spatial Relations
The following lecture is summarized from the Space Syntax Online Training Platform developed by Space Syntax Laboratory at The Bartlett, University College London.
Further Reading: The Social Logic of Space (108–113); Hillier & Iida, 2005; Hillier et al, 2012
What is Space Syntax
Space syntax is a set of techniques for analyzing spatial layouts and human activity patterns in buildings and urban areas. It is also a set of theories linking space and society. Space syntax addresses where people are, how they move, how they adapt, how they develop and how they talk about it.
Four Components of Space Syntax
Space syntax comprises four fundamental components, which are used in all space syntax applications.
- Representation of Space
- Analysis of Spatial Relations
- Interpretive Models
- Theories
1. Representations of space
Space is described in terms of discrete spatial elements that relate to human behavior as well as the unique geometric and configurational properties of the networks created by these elements.
Spatial Relations to Human Behavior
1. People move in lines — People move in linear spaces such as corridors, streets, boulevards, avenues and alleys. Linear spaces and the potential of movement in these can be represented in the form of an axial line, a segment or a road center line.
2. Co-presence in convex spaces — People interact in a convex space, meaning the space in which all people can see all others.
3. Perceive Changing visual fields — An Isovist is a representation of everything that can be seen directly from a given point in space. When we move through the complex patterns of space in built environments, the isovist is changing and the accumulation of these isovists represents an enduring picture of the pattern of space as a whole.
Graph Theory
Space is also represented as a Graph in which the discrete spatial element (eg. convex space, axial line, segment, or isvoist) is denoted as a small circle, or a node, and its relationship with other elements is denoted as a line, or a link which joins the circles.
The graph represents the configurational relations between those spatial elements, which can be applied to both building and urban studies.
For example, the spatial layout of a hypothetical house is represented as a graph, where each room is denoted as a circle and the access relations between the rooms as links.
Another example is a hypothetical settlement. The street lines are represented as circles, and the street intersections as links; this is in contrast to the conventional representation of a street network in transport modelling, where the street intersections are denoted as circles and the streets as links. This is also known as an Inverse Graph.
2. Spatial Relations
Justified Graphs
Complex spatial relations, represented as a graph, can be visually simplified by drawing a justified graph. A circle is put at the base representing the root of the graph, and then all circles directly connected to that root — meaning depth 1 — are aligned immediately above it and all circles at depth 2 are directly connected to those at depth 1, and so on until all levels of depth from that root are accounted for.
When justified graphs are drawn from different root spaces, the shape of the graph changes. Each graph gives a picture of what the whole layout looks like from that particular space. The key is that a spatial layout of either a building or a settlement not only looks different but is different when seen from different perspectives.
Concepts of Distance
One of the basic ideas in measuring spatial relations is the concept of depth, meaning the distance between any pair of spatial elements. Three definitions of distance are used:
1. Topological distance, the number of turns from one space to another (see figure A)
2. Angular distance, the angular change from one space to another
3. Metric distance, the Euclidean distance in meters from one space to another
Different spatial patterns will be generated by assessing the three types of distance.
Syntactic Measures
Relationships between spatial elements result from their configuration. These relationships can be objectively analyzed using various measures, included among which are integration and choice. These two measures reflect the two fundamental elements in human movement: firstly, the selection of a destination, and secondly, the selection of a route. One measures the ease of access (integration) and the other measures the passing flow (choice).
_Exercise:
1. Integration (Closeness)
One of the fundamental syntactic measures is integration, or mathematical closeness. This is the calculation of how close or how accessible each spatial element is to all others under each definition of distance, such as the least angular distance. For example, the figure below illustrates how easy it is to go from different intersections to the same destination, following smooth and continuous routes.
Integration can be used to assess how much potential the space has as a destination for movement, called the to-movement potential, by generating an integration pattern.
2. Choice (Betweeness)
Another widely used syntactic measure is choice, or mathematical betweenness. This measures the degree to which each spatial element lies on the shortest paths, under each definition of distance, between any pair of spatial elements.
Choice assesses the potential of the movements passing through each space, called the through-movement potential, in contrast to the to-movement potential measured by integration. Through-movement patterns can be examined by producing a choice pattern.
3. Scale (Radius)
In order to analyze the spatial properties found at different scales, the concept of radius is introduced to serve as a tool for selecting sub-systems which can be analyzed around a particular space (eg. by walk or by car). For example, we can select all spaces up to 400m, 800m, 2km or 5km from a particular space.
As a result, we have a package of measures to assess spatial configuration varying different types of distance and/or radius. These can potentially yield a large set of possible syntactic measures.
4. Other measures
Other syntactic measures comprise connectivity, total depth, entropy, intensity and so on. The measures most commonly used in space syntax are angular choice and angular integration at various metric radii, because these measures have been supported and verified by a large number of studies and practical applications.
3. Interpretive Models
Spatial models are developed to analyze, describe, explain and forecast different kinds of spatial and socio-economic phenomena. Practically, models are created to investigate empirical phenomena such as urban movement, urban crime, and centrality as a process as well as for general processes such as spatial intelligibility.
- Space & Movement Model
- Space & Activity Model
4. Theories
Theories of the relations between spatial and social patterns are established to explore whether and how space is internalized into socio-economic processes through which the built environment is created. This has been done in two ways. Firstly, theories can be used to look for commonalities in the pattern of models across functions and cultures. One example is the theory of the generic city. Secondly, theories can use space syntax tools to explore what happens to spatial patterns if objects in space are deployed and shaped in different ways.
Case Studies
Trafalgar Square
Space Syntax
Seven Dials
KPF UI
Urban Pulse
KPF UI
