baba urban forms

What is urban form and what factors influence it?

Urban form is the physical characteristics of a city, and considers:

· Size

· Shape

· Population density

· Land-use patterns

Early urban areas were established in particular places because:

· Access to natural resources - wood, stone and water supplies (drinking and fishing etc.)

· Fertile soil for food production

· Defensible - on top of hill etc.

Over time, the urban form changed to centres of production, trade and commerce influenced by physical and human factors.

What physical factors influence urban form?

Topography: Physical features influence growth of cities - steep slopes can be difficult to build on but provide excellent views and exclusivity (Hollywood etc.) or segregation for poorer housing (slums of Mexico City). Vast, flat plains encourages low density building due to space.

Resources: Lakes, rivers and seas limits urban growth (Chicago, Southampton etc.) or encourages growth along its course and coast (London, Los Angeles etc.). City cores (retail and business) are centred around the waterfront and ports, rather than centralised (Liverpool, Cardiff, and Toronto). Natural resources lead to production and growth of urban areas - coal (Cardiff), wood (Chicago), steel (Sheffield).

Ground type: Some types of land are easier to build on than others. Chicago is built on swampland and was raised above the ground, allowing expansion and growth. Venice is also built on swampland, but canals are used as roads and growth is limited.

What human factors influence urban form?

Planning: Can be planned or unplanned. Many LDE cities expand due to informal settlements (slums) such as Mumbai or Mexico City, whereas, London or Singapore are very much planned to include open spaces, leisure facilities and infrastructure. Planning is needed to manage population increase along with their needs and demands for mobility and housing. Governments can block or encourage development and political policies influence success or failure of the urban form.

Infrastructure: Rise in technology requires electronic infrastructure and work hubs in centres or science parks on urban fringes. New developments follow access routes (motorways etc.) but also form linear growth as a result (Southampton).

Value of land: Urban cores usually have the highest land value and are considered the most profitable by retail and the food industry. Land value decreases outwards due to availability of space for development. However, 'shocks' in the economy (pandemics, recession, outward migration etc.) can change the desirability and therefore, the land value of urban areas.

What are the characteristics of mega/world cities?

Megacities have rapid growth and slow planning systems, creating a chaotic urban form. The form varies from city to city over time and space, but there are some generalisations:

· Urban sprawl and fringe developments

· High density living

· Segregation

· Automotive bias - car, lorries and roads etc.

· Environmental issues

· Ageing infrastructure

· Redevelopment and renewal

· Urban intensification - high rise buildings

Contrast Between HDE and LDE Megacities:

· CBD: HDE - Central zone of retail, businesses and entertainment; LDE - Central zone of shops, businesses and entertainment

· Land Value: HDE - High in city centre and decreases with distance; LDE - High in city centre and decreases with distance

· Housing (HDE): Housing value increases with distance from the centre. Housing is high density, high rise, with wages unable to keep up with rents and costs. Many areas of poverty, segregation and ethnic minorities

· Housing (LDE): Housing value decreases with distance. Housing is high density, but there is also high cost, luxury housing to accommodate wealthy immigrants and business executives

How do housing and urban fringes contrast between HDEs and LDEs?

Housing (continued):

· Whilst land value is lower in rural and semi-rural areas, houses are usually well spaced, larger, newer and more expensive. This attracts families, the wealthy and high wage earners, keeping areas exclusive and high priced

· Housing estates are constructed with higher density living but with gardens and good access routes. Prices are still high, but can be more affordable than closer to inner city

· There are usually zones of medium-cost housing which may have begun as informal but gradually been improved through government planning and grants

· Low-cost housing on outskirts/fringes of the city with informal housing and limited (if any) access to services - water and power

· Poverty, informal employment with low-wages are common. Poorer migrants tend to settle here

Urban Fringe:

· Science parks, retail parks, super and hypermarkets along with light industry are constructed here. Land is cheaper and has good access to other parts of the country

· Industrial areas are built along transport links and centred around informal settlements to attract high turn over of cheap labour

What are the characteristics of different urban forms?

Pre-Industrial: Unaffected by industrial development. Lower socio-economic groups surround the urban elite. Centre is dominated by historic buildings with elite residential zones. Delineation between residential and commercial districts is blurred.

Industrial Cities: Similar activities and people are grouped together. Clear pathway of building arrangement due to land value decrease from centre to periphery. CBD is central. Zoning of housing and industry. Manufacturing based industry.

Post-Industrial: Urban mosaic. Many smaller zones and no central CBD. Social polarisation. Multi-nodal structure. CBD is less dominant. Service sector dominant.

Automotive Bias: Public transport development is integral in planning between housing and transport hubs. Suburbanisation increased decentralisation from the 1950s along with increased road use. Major road networks. Housing centred around rail and bus routes. Movement of industry and retail to fringes.

African Cities: Grown from colonial past with little industrialisation. Rapid growth recently has forced changes to older established zones and peripheral growth. Lack of resources and planning, urban form is chaotic. Political, cultural and historic dominant CBD. Industry is centred around transport routes. Middle class housing on periphery with good road networks. Marginal land is dominated by informal housing.

Socialist Cities: Based on a classless ideology of everyone lives in the same type of housing regardless of location, wealth and employment. Block housing is provided near to employment and services. CBD is administrative and politically dominant. CBD is imposing with prestigious buildings, central squares and police presence. Homogenous blocks of high-rise flats. Neighbourhoods have low order, local services. Districts see high order good services and entertainment.

What are the spatial patterns of land use?

Land use can be considered the function of place; the main activities of urban areas. Can be industrial, financial, research and development, homes, or leisure. Cities can have more than one function. Most lucrative is tertiary and quaternary services.

Typical land use within cities are: Housing, Industry, Services, Transport.

One feature of all urban areas is the spatial sorting of functions and people. Similar activities and types of people tend to cluster together to create a mosaic within the built-up area. The mosaic varies from settlement to settlement, over time and space.

What is Burgess's concentric zone model?

Burgess's concentric zone model 1925:

· One of the earliest theoretical models to explain urban social structures and based on the city of Chicago, USA

· It suggests that as cities develop and grow, they move outwards in concentric zones

· Business activity is within the CBD, as this has the most accessible point

· Next is the "zone of transition", with older houses converted in light industry and flats

· In-migrants tend to be drawn to this zone for its cheap housing

· Housing improves with distance from the CBD, allowing movement away from the centre and pollution

· High class residential housing is occupied by middle class with its newer and larger houses

Simplified model zones: Core, Inner-City Ring, Suburban Ring, Urban Fringe.

What are the limitations of the Burgess model?

The model does not take into account the physical landscape

· This was based on Chicago, and yet the city is on the edge of the Great Lakes

· Burgess did not consider the development of commuter towns

· Urban regeneration, renewal and gentrification has changed inner city housing status

· Model does not consider social/council housing

· Decentralisation of shops and industry does not fit with the model

· Fringe developments are not included

· A simple model that explains basic urban growth

What is Hoyt's sector model?

Hoyt, a student of Burgess, stated that business activity is still within the CBD.

Hoyt's sector model 1939:

1. Public transport routes terminated at or near the CBD, giving access for most people

2. Industry was noted to follow particular transport routes or corridors

3. High class residential areas often developed where there were distinct physical or social attractions (e.g. river)

4. Low class residential areas was therefore, confined to unfavourable locations (ugly, less transport links etc.)

Hoyt's sector model - note that high class housing is 'ringed' by middle class housing and is along a corridor, with direct access to the CBD.

Limitations to Hoyt's model:

· Based on Chicago and again makes little reference to the physical environment

· No reference to out of town developments or commuter settlements

· The growth of a sector can be limited as land use is in blocks (contained)

· Some cities appear to follow this model as it looks at the effects of transport and communication routes

What is Harris and Ullman's multi-nuclei model?

Harris and Ullman's multi-nuclei urban model 1945:

1. Harris and Ullman argued that cities do not develop around a single centre but around important, multiple nuclei

2. CBD still exists but not always at the centre of the city

3. Low class residential housing tends to be in areas of cheaper land around industry (heavy or light)

4. High and middle class residents can afford to avoid living next to industrial areas; these areas are normally on a different side of the city to industry

5. There are areas of development outside of the main settlement around new nuclei like out of town shopping centres

6. The model is the first to take into consideration of the complexity of the city and its periphery

7. It considers that the CBD is not the only part of the city that affects land use

8. However, it is still a simplification of urban land use and the physical landscape is not fully considered

What is bid rent theory?

Bid rent theory shows how the price and demand on land changes as the distance towards the CBD increases. Different land users will compete with each other for land close to the city centre. Shops wish to maximise their profitability, so they pay more for land closer to the CBD and less for land further away from this area. This is based upon the idea that the more accessible an area, the more profitable it is going to be. The amount people are willing to pay is called Bid Rent.

The bid rent model shows:

· Shops and offices can afford high land values of the CBD

· Industry cannot afford the highest land values so is found away from the CBD

· Housing can only afford low land values

· As distance from the CBD increases there is less competition for land, so values fall (distance decay)

Limitations:

· Very simple, with only 3 broad zones

· It assumes straight lines for cost curves and no scale

· Too graphical, compared to map or plan

· Doesn't take into account transport networks, planning decisions or physical environment

· Alonso identified that occasionally low income groups are found in the centre of a city, they were in high density cramped residential buildings as rents were high

What is peak urban land surface value?

This is a major factor in sorting land uses and people. Activities and groups differ in what they can afford. Urban land value tends to decline outwards from the core. But there are other factors too:

· Geography of the place, flood plains, rivers, waterfronts

· Historical factors

· Economic factors

· Social factors

· Urban land managers – professionals who distribute and control resources – planners, governments, employers, developers, service providers

What is LDE land use like?

CBD in centre as normal

· Industry starts in centre and develops out around transport and water routes

· Zone of lower to middle income residence (also called zone of maturity) is where there is a mixture of old and newer housing occupied by middle classes

· Colonial - high class (elite) residential often develops in a spine out from the city centre

· Around the colonial is a wide range of housing but in the process of improvement e.g. government improvement projects

· Zone of squatter settlements is often on the most undesirable land at the periphery of a city

Based on Griffin and Ford's LDE model of Latin American land use:

· Colonial CBD

· Traditional CBD

· Market Zone

· Zone of Lower to Middle Income Residential

· Mining and Manufacturing

· Zone of Slums and Squatter Settlements

· Major Road

· Local Street

Examiner Tip: Models try to explain differences in structure within cities. Each model has its limitations. If you study a city, you must avoid trying to fit it into one model - it probably fits into two or three - Tokyo. Each city is unique and will have its own structure and life.

What are mixed-use developments and fortress developments?

Modern urban areas have undergone changes to include a range of features. These include:

· Mixed-use developments in town centres

· Fortress developments

· Edge cities

· Gentrified areas

· Cultural and heritage quarters

Mixed-use Developments: Residential, commercial, cultural, institutional, entertainment and leisure uses are blended/interconnected, safely and easily accessed by people. Developments are planned by local councils, usually with private investment. Aim is to attract people back to city centres through opportunities to work, live and relax in one place. Examples: BedZed, Hackbridge, London; Trinity Square, Gateshead, Tyne and Wear.

Fortress Developments: Gated and guarded communities of 'safe' living space and/or retail use. Often located in suburban regions of large cities with limited access. Deliberately designed around security, protection, surveillance and exclusion. Divisive and promotes social segregation as costs involved means only higher socio-economic groups can afford to live in or use them. Common in EMEs such as Brazil, China and South Africa. USA has numerous sites in major cities - Hollywood, LA and along the Mexico Texan border etc. London has begun to build gated, monitored communities - Kensington Gardens.

What are edge cities and gentrified areas?

Edge Cities: Self-contained areas of offices, retail and leisure centres, close to major transport links on the outskirts of city centres. Land is cheaper and have planned housing estates - usually with commuter routes into city centres. Majority of edge cities developed due to decentralisation and suburbanisation and the rise of car ownership. Most common in USA - Detroit, Dallas; Croydon, UK.

Gentrified Areas: Unplanned inner-city regeneration, where wealthier people move into run-down, cheaper inner city streets and improve it, one house at a time. It is an affordable route onto the property ladder. This has a multiplier effect - property prices increase and attract other people into the area, this feeds into gaining local service upgrades until the area has improved physically. Established residents are usually excluded or displaced as the cost of living increases leading to social and ethnic segregation. Examples: Jericho, Oxford; Tower Hamlets, London; Fishponds, Bristol.

What are cultural and heritage quarters?

Cultural and Heritage Quarters: These are planned areas focused on the history or character of a city. Aim is to encourage growth and revitalise the local economy in the arts and creative industries. Often developed by local councils and regenerate former industrial areas. Examples: Liverpool World Heritage; Birmingham Jewellery Quarter; Bristol Harbourside; Swansea Bay.

Select the correct pair of consequences that result from the development of edge cities. (1 mark)

Gentrification of inner-city areas Social segregation

B Loss of rural habitats Increased photo-chemical pollution

C Deindustrialisation Gentrification of inner-city areas

D Loss of rural habitats Social segregation

A: D. With the development of edge cities there is a loss of rural habitats because land is built on and edge cities are on the outskirts of cities. There is an increase in social segregation because in HDEs, whilst land is cheaper with distance, the value and desirability of housing becomes more expensive, excluding those in lower pay bands, but also increasing the need for private transport due to the distance outside the core of the city.

Note that the question asks about the consequences of (the result of), not the cause of building edge cities.

What is postmodernism in urban areas?

Cities are dynamic and work at evolving to new space and form. Many cities, particularly HDE's, are moving away from the typical patterns of functional land use and architectural uniformity of the post-industrial/globalised urban form. These post-modern western cities, are focused on service and knowledge, with a return of middle-income people from the suburbs into city centres. It accompanies gentrification, upgrades to old or rundown housing and heritage quarters into trendy, flagship homes and developments. Demolishing of 'older' parts of a city's core to replace with new cores or self-contained, gated (fortress) urban developments to reduce car usage and emissions. It attempts to emphasise new ideas in design, living space and community but social and economic inequalities are growing. All cities have elements of post-modernism e.g. the Gherkin and Cheesegrater in London, the Guggenheim Museum in Bilbao or 'Antilia', a private home in South Mumbai and 'The Imperial', a twin-tower skyscraper in Mumbai.

What are the characteristics of a postmodern city?

Postmodernism reflects social and economic changes from late 20th century in most western cities. There are a number of characteristics associated with these urban changes:

· Multiple centres with varying purposes

· Focus on tertiary and quaternary industries

· Buildings are less uniform

· Planning is focused on city form over functionality

· Increased ethnic diversity, but wider social and economic inequalities

Post-Modern Cities:

Change Characteristics

Government Partnerships between public and private sectors. Services provided by private sector rather than public sector. Unfettered movement of international finance

Economy Dominating by service and high tech sectors. Globalised economy. Economy of consumption

Planning Voices of many stakeholders considered. Space is fragmented by focus on form over function

Structure Fringe/edge cities. High-tech corridors. Messy, multi-purpose structures

Architecture and Landscape Different styles, juxtaposed. Historic and cultural recognition. Symbolism and meaning incorporated

Culture and Ethnicity Social polarisation. Highly fragmented. Large diversity