URBP7005 Chap.6 Urban Form and the Movements That Shaped It
Urban Form and the Movements That Shaped It
Three definitions, and why the third is the working one
Three published definitions are put side by side. The first takes urban form to mean how a city is physically shaped and designed. The second takes it to mean the arrangement in space of the heavy, immobile, long lasting things a city is made of.
The third takes it to be a bundle of properties covering how land is used, how the transport system runs and how the place is designed. The third is the one this course works with, because it is the only one that already contains land use and movement, which are the two things a plan can change.
Why form matters is put simply: the growing concerns are congestion, pollution and energy consumption, and the policy options are price and land use.
A century of schemes, each fixing the last
Land use zoning arrives in 1890 as an economic solution for low density affordable housing at the fringe, and is then charged with imposing rigidity, encouraging separation by class and retail strip development, and discouraging mixed use and pedestrian areas.
The garden city answers the industrial town with three magnets and decentralised self sustaining communities, and is built at Hampstead as around five thousand properties for sixteen thousand people.
A traffic scientist answers road casualties with segregated layouts; a 1929 statement answers the unstructured suburb with a neighbourhood unit sized to one elementary school; and a 1934 proposal answers the city itself with radical decentralisation.
From designing plans to analysing cities
Two bodies of work turn design judgements into properties that can be computed.
One argues that cognitive maps emerge from five elements, paths, edges, districts, nodes and landmarks, and that the resulting mental images affect movement, travel behaviour and accessibility.
The other quantifies spatial configuration at building and neighbourhood scale, distinguishing routes by whether they minimise metric, angular or topological cost, and classifying whole cities by the strength of their centre, radials and lateral connections.
The question the field has not answered
A short editorial set for this session asks how tall we can go and how compact we can get, and declines to answer either.
Its argument runs through geometry: as mass grows the ratio of skin to volume falls, and since volume requires energy the shortfall must be supplied artificially, which is an argument for height until the energy of internal movement and the cost of construction are counted.
Compactness does not require height, the most compact three dimensional form is infeasible, and the verdict offered on three very differently shaped world cities is that we simply do not know.
What this chapter covers
- 01
Three competing definitions of urban form
- 02
Congestion, pollution and energy against price and land use
- 03
A sectoral table of interventions and their claimed co-benefits
- 04
Zoning from 1890 and the effects attributed to it
- 05
The garden city, the three magnets and Hampstead
- 06
Traffic segregation and the road hierarchy
- 07
The neighbourhood unit stated in numbers
- 08
Radburn, the superblock and the earliest culs-de-sac
- 09
Five cognitive elements and the legibility of a plan
- 10
Configuration analysis and three city types
- 11
Six types of urban expansion
- 12
Allometry, height and the open compactness question
Defend or reject a century old settlement pattern
- 2Identify the pattern and say why age alone is not an objection.
- 4State the problem each element was answering.
- 3Say which element the later evidence undermines, and what replaces it.
Key terms
- Urban Form
- A composite of characteristics relating to land use patterns, the transportation system and urban design, which is the working definition used through this course.
- Neighbourhood Unit
- A residential unit sized to one elementary school, bounded by arterial streets, with shops at the perimeter, internal streets designed against through traffic and a share of the area in parks.
- Form Based Zoning
- A way of regulating development towards a chosen urban shape, fixing the built form an activity must take rather than which activity is permitted.
- Space Syntax
- An analytic approach for representing and quantifying spatial configuration at building and neighbourhood scale, used to relate configuration to functions such as pedestrian movement.
- Route Betweenness
- A configuration measure identifying route sections with high path overlap and therefore high through movement potential.
- Leapfrog Expansion
- A growth type in which new development skips land at the edge, leaving serviced gaps behind and committing the authority to infrastructure it pays for twice.
- Allometry
- The relationship between the mass of a structure and its surface area, used in the session to argue that energy demand and skin area do not scale together.
Urban Form and the Movements That Shaped It FAQ
Which definition of urban form should I use in a paper?
Say which one you are using in the first paragraph, because it changes what counts as evidence. If form means physical form and design, your evidence is architectural. If it means the spatial pattern of large permanent objects, your evidence is the arrangement of blocks and infrastructure over time.
If it means the composite of land use patterns, transport system and urban design, which is what this course works with, then your evidence has to include the land use schedule and the network.
Does the literature show that compact cities are more sustainable?
It shows something narrower and better supported: dense urban structures reduce greenhouse gas emissions from transport, limit building energy consumption, and protect farmland and natural areas around the city. It does not settle the overall question.
The editorial set for this session treats the energetics of tall buildings and the comparison across whole city forms as unresolved, and the health evidence covered later in the course runs partly the other way.
Why does the course spend time on movements that are a century old?
Because three of their inheritances are still live in practice. The catchment idea survives wherever a plan sizes a neighbourhood to a school, a clinic or a station. The open space share survives as a development control standard. And the traffic segregation instinct survives as the road hierarchy, which is precisely what the connectivity and walkability measures in the following chapters put under pressure.
Assessment move
Pick one neighbourhood in your case city and identify which of these movements shaped it, using the street pattern rather than the date. Then write two sentences: what problem that pattern was solving, and which of the two policy levers, price or land use, could change it now. That pairing is the physical layer of almost every argument this course asks you to make.
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