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2.1.8 Theoretical Model of City Structure

City structure depends on kind, location and density of activities distributed across
space in urban areas.

An urban neighborhoods
having physical elements as buildings, landscapes, open
space and transport network

A model is a representation of a reality or expression of certain relevant characteristics
of the observed reality. Reality consists of the objects or system that exists, have
existed or may exist.
Urban patterns of city structures are influenced by,
Concentrations- refers to
 different distribution of population and economic activities focused on the center
of city and
 clustering around important activity points such as transportation routes,
factories or major stores.
Decentralization - location of activity away from the center of the city.
Segregation - sorting out of population groups ; the individuals role in the total organization of
city life.
•
Many factors influence the location of an activity within a city
•
Does a predictable land use pattern result from the interplay of these factors?
•
The answer is to create models that describe and simplify the relationship among the
different social, economic and geographic factors
Three most widely used models are:
1. Burgess Concentric Model
2. Sector Model
3. Multiple Nuclei Model
I. Burgess Concentric Model

Ernest W. Burgess, a sociologist at the University of Chicago – 1925

Based on human ecology theories done by Burgess and applied on Chicago
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
Give the explanation of distribution of social groups within urban areas

This concentric ring model depicts urban land use in concentric rings: the Central
Business District (or CBD) was in the middle of the model, and the city expanded in
rings with different land uses.

It is effectively an urban version of Von Thunen's regional land use model developed
a century earlier.

Composite effect of market forces upon land use arrangement: Depicts the use of
urban land as a set of five concentric rings with each ring devoted to different land
use.

City expands and inner zones increase its area by encroaching upon the next outer
zone.
The five concentric zones according to socio-economical status identified are as follows:
1. The center was the CBD
2. The transition zone of mixed residential, industrial and commercial uses
3. Working class (low class) residential (inner suburbs)
4. Better quality middle-class residential (outer suburbs) or Zone of better Housing
5. Commuters zone (high class residential)
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1. Central Business District (CBD)
A central business district CBD is a central activities district which is highly commercial and
often geographic heart of a city.
•
This part of a city is commonly referred to as
 downtown in the US
 city center in Canada, Ireland and UK
The central business district (CBD) has the following characteristics –
•
Has the departmental shops, large offices, main railway and bus stations, many
churches, pubs, clubs and cinemas and the town hall
•
The main roads head into the CBD.
•
The value of the land is greatest here
•
Due to the high cost of the land, buildings are built upwards
•
CBDs suffer from the worst traffic congestion
•
It is often the oldest part of the city
•
It may have a grid-iron street pattern, that is parallel straight roads and other roads
running at right angles
2. Zone of Transition
•
Area between the factory zone and the working class zone
•
The zone of transition is an area of flux where the land use is changing.
•
It encircles the Central Business District (CBD).
•
The buildings are changing from CBD usage to residential land use.
•
Characterized by a mixed pattern of commercial and residential land uses.
•
Rooming houses, small apartment and tenements exist here, which attract low-income
groups.
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•
‘Slums’ are liable to be found with their submerged regions of poverty, degradation and
disease and their underworlds of crime.
•
Zone for regeneration: commercial activities rapidly displace residents as CBD expands.
3. Working Class Residential Homes
•
The third zone which is inhabited by workers who have escaped from the area of
deterioration but who desire to live within easy access of their work.
•
Not haphazard settlement as in transition zone but closely built houses are
characteristics of this zone.
•
There is no vehicular movement in this zone and hence the residents have to go to CBD
for easy transportation.
4. Better Quality Middle-class Homes
•
The fourth zone is the middle class residential zone lies between working class and high
class residential zone.
•
The quality of housing is better than working class homes with slightly lower density
•
Semi-detached houses with little bit gardens
5. Commuter Zone (High Class Housing)
•
The last zone is the commuter’s zone consisting of higher income families clustered
together.
•
This zone is filled with spacious lots and large houses > rich pressed outward to avoid
the increasing congestion
•
Social heterogeneity brought to their area by an expansion of fourth zone.
Before 1870’s, American city had mixed neighborhoods. In 1871, great Chicago fire burnt out
the core leaving one-third of its buildings. the city was rebuilt on a new concentric pattern. In
Chicago, all five zones were in its early history. The actual map of Chicago does not exactly
match the simplicity of Burgess’s Concentric Zone. It is evident that the wealthy continue to
monopolize certain high value sites within other rings especially “Chicagos" Gold Coast which
should be parts of zone of transition.
Rich tended to monopolize hills, lakes, and shorelines, whether close to or far from the CBD.
Neither Chicago nor any other cities fit perfectly into this ideal scheme. In all cities local and
outside transportation converge in the CBD , department stores, city hall and the economic,
cultural and political life centers . The relation of centralization to the other processes over a
million people daily enter-leave Chicago’s Loop.
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Criticism
•
Though portions of each zone did exist in most cities, rarely were they linked in such a
way as to totally surround the city.
•
Burgess, as a sociologist, overemphasized residential pattern and did not give proper
credit to other land uses.
•
Despite these criticisms Concentric Zone Theory was fairly accurate in describing the
cities of 1925.
•
In fact, many of the zones can still be seen in contemporary cities, particularly the zone
of transition (Slums) around the central business district.
II. Sector Model
 The sector model, also known as the Hoyt
model, is a model of urban land use proposed in
1939 by economist Homer Hoyt.
 It is a modification of the concentric zone model
of city development.
 States that a city develops in sectors, not in rings

Certain areas are more attractive for different activities because of an environmental
factor or by mere chance.

Hoyt modified the concentric zone model to account for major transportation routes

According to this model most major cities evolved around the nexus of several important
transport facilities such as railroads, sea ports, and trolly lines that emanated from the
city's center.

Hoyt theorized that cities would tend to grow in wedge-shaped patterns, or sectors,
emanating from the CBD and centered on major transportation routes.









It is a monocentric representation of urban areas. He posited a CBD around which other
land uses cluster
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
But important factor is not distance from CBD as in the concentric zone model, but
direction away from CBD

As growth occurs, similar activities stay in the same area and extend outwards

The Hoyt model realized that transportation (in particular) and access to resources
caused a disruption of the Burgess model.

For example a rail line or major highway to a nearby city may result in business
development to preferentially develop parallel to the rail line or major highway. So one
side of a city may be completely industrial with another sector may be completely rural.

Recognizes the existence of land use zones, but suggests that there are sectors or
wedges of land uses in the city

In this model, zones are pie shaped wedges radiating along main transportation route.

Poorer people live adjacent to industrial near their jobs

Rich live on the opposite side of town far from the industry and poor >>middle income in
between

Hoyt’s sector model is simply a concentric model modified to account for the impact of
transportation systems on accessibility
Factors that affect the high rent sector to expand:

High-grade residential growth tends to proceed from CBD, along established routes
of travel, towards another sectors of high rent buildings; eventually linking the two in
a wedge shape sector.

Zone of high rental area tends to progress towards the high ground which are free
from risk of flood.

They spread along the rivers, oceanfront where no industries are located and total
environment is better for residential purpose.

High rental residential area tends to grow outward i.e. towards the area of city <
away from dead-end or is restricted by natural or artificial barriers.

Trend of the monumental buildings, offices, banks etc. pull the high residential area
to grow

Move along the route of fastest transportation.

A high rent sector will move toward open space.

A high community rarely moves into an occupied lower income neighborhood; they
prefer to build new structures on vacant land where they can control the social
environment.
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Hoyt Sector Model
III. Multiple Nuclei Model

In 1945, two geographers, Chauncay Harris and Edward Ullman suggested multiple
nuclei model.

A city developed with equal intensity - 'Multiple nuclei".

The CBD cannot be a sole generator of change.

Equal weight must be given other centers - the old community, industrial district, a lowincome area that developed because of some stigma attached to the site.

In other words, the city grew from a number of unrelated points, not from a single sector.

Multiple-Nuclei model is a model of urban land use in which a city grows from several
independent points rather than from one central business district.

Each point acts as a growth center from a particular kind of land use, such as industry,
retail, or high-quality housing.

As these expand, they merge to form a single urban area. The CBD is not the only
generator ofchange. Some centers or nodes include; ports, universities,airports,parks,
neighborhood business centers.

The theory was formed based on the idea that people have greater movement due to
increased car ownership.

This increase of movement allows for the specialization of regional centers (e.g. heavy
industry, business park).

The model is suitable for the big and expanding cities.
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
The number of nuclei, around which the city expands, depends upon the situational as
well as historical factors.
Harris & Ullman
Harris and Ullman rooted their model in four geographic principles.
1. Certain activities require highly specialized facilities, such as accessible transportation for a
factory or large area of open land for a housing tract.
2. Certain activities cluster together because they profit from mutual association. One such
cluster could be banks, used car lots, and jewellery stores
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3. Certain activities repel each other and will not be found in the same area e.g. high rent
residential and industrial areas.
4. Certain activities could not make profit if they paid high rent of the most desirable locations.
2.1.9 Central Place Theory

Central place theory is a geographical theory that seeks to explain the number, size and
location (spacing) of human settlements in an urban system.

It was developed by German geographer Walter Christaller in 1933.

Central place theory is the idea that urban locations are arranged spatially in a pattern
of hexagons that are nested based on the size of the urban location.

The central place is so called because it is centrally located to maximize accessibility
from the surrounding region.

Hierarchy of economic activity from the population size and the distance

Hitler used in planning new territories.

A central place is any location that offers a service or a product to its surrounding
market region

The task is to delineate the geographical relationship among different central places

The theory seeks to relate central places to their hinterlands (neighbours)

However, the theory is only concerned with the intensity and location of service industry;
hence provide only partial explanation of regional structure.
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CONCEPT
Classification of Service Activities
Classified into four homogenous trade groups on the basis of functional qualities:
a) Repair work and other services
b) Distribution and transport of goods
c) Processing and distribution of information
d) Various personal and collective needs such as security and health
Threshold Population

It is the minimum population necessary to support any service activity

If the population falls below the threshold level, the activity will run at a loss or will have
to be closed at last and vice versa

Frequency of use of the service is vital for the threshold population
Market range

It is the distance which people are willing to travel to
reach the service

Upper (farthest) and lower (shortest) limits

More expensive and specialized goods upper limit is
high

But for more frequently demanded goods (cheaper
goods) the upper limit range is smaller

Though seems to be simple function of linear
distance, it is influenced by time, cost factor,
importance of the service area and income level
Assumptions
To develop the theory, Christaller made the following simplifying assumptions:

An isotropic (all flat), homogeneous and limitless surface

An evenly distributed population

Evenly distributed resources

All settlements are equidistant and exist in a triangular lattice pattern.

Perfect competition and all sellers are economic men maximizing their profits.

Consumers are of the same income level and same shopping behaviour.

All consumers have a similar purchasing power and demand for goods and services.
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
Consumers visit the nearest central places that provide the function which they demand.
They minimize the distance to be travelled.

No provider of goods or services is able to earn excess profit (each supplier has a
monopoly over a hinterland).

There is only one type of transport and this would be equally easy in all directions.

Transport cost is proportional to distance travelled in example, the longer the distance
travelled, the higher the transport cost.
Various Stages of Development

Small-scale industry might service a circular market
area as illustrated in Fig. 1

People are willing to travel up to a distance ‘a’ to
purchase

If retailing is profitable, other enterprises may develop
their own circular market areas

Spatial competition will develop between providers of
the service activity as shown in Fig. 2
Fig. 1

But at this stage not all the market area is being served

With improved transport and communication, consumers are willing to travel further

Market areas will expand with radius ‘b’ as shown in Fig.
3

The expanded market area covers most of the landscape

Market areas are now touching but even now certain
consumers are still left out
Fig. 2

Fig. 3
Now the market areas with radius ‘c’ overlap as shown
in Fig. 4

In such area consumer actually use more than one
center

Fig. 4
However, to minimize transport costs the nearest center will be chosen
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
Development of hexagonal market areas around a
system of central places as shown in Fig. 5

Smaller central places develop at the points where
the hexagonal service areas meet

The resultant central places will be more than
original

Limited number of higher order central places

Three levels in a hierarchy of central places are
apparent
Fig. 5

‘A’ centers possess service activities, local stores to large supermarket

‘B’ centers possess a more limited range of activities

While ‘C’ centers only possess a small number of service activities
Defects of this Theory

Only talks about the service element and not other factors such as natural resources,
institutions manufacturing center etc

The theory is only ideal for rural areas for the assumption of isotropic land

The theory also assumes a uniform distribution of population, services, income level
which is unlikely to occur.
2.1.10 Modern Planning Thought of Le Corbusier

Le Corbusier is one of the pioneers who introduced the idea of living in a city that is
planned, designed and built.

He promoted hugeness, hierarchy and centralism in city structure.

He proposed cities could be anywhere: free of context, history, or tradition.

According to him, a planner should treat a city as a blank piece of paper or a clean table
cloth where structures are to be erected.
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
Being the member of International Congress of Modern Architects (CIAM), he reexamined and created four basic elements of urban biology; sun, space (air),
vegetation, and concrete & steel.
 Sun - represents ample amount of heat and light
 Space - represents the volume
 Vegetation - represents the open spaces with greenery
 Steel and concrete - represents the skyscrapers with steel structures and curtain
panels.

By investigating city’s character, he resulted as forms of “3 Human Establishments”;
farming unit, radio-centric city and linear city.
 Farming unit: refers to the space for agriculture and village that serve it.
 Radio-centric city: the urban concept of city with high level of concentration. It is
centralized with high density tall skyscrapers with large parks around it. This is also
called tower of the park. The low rise residential buildings are placed around it.
 Linear city: stated that the town should be along the lines of railway tracks or river
banks or highways in linear forms with easy accessibility of services.

He used the concept of urban settlement which was fusion between the concentric form
of the garden city and ribbon form of the linear city.

Centre of the city: consist mainly skyscrapers > high rise high density living >
exclusively for commercial use leaving more open space (built up area not exceeding
5% with 95% greeneries) > surrounded by belts of residential areas in the staggered
form with setbacks.
La Ville Contemporaine, Corbusier’s Unrealized Project

Separation of social functions: separate zones for workplaces, residences, shopping
and entertainment centres, monuments and government buildings.
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
Where possible, work zones were to be further sub-divided into office buildings and
factories.

He calculated the air, heat, light and space requirements of humans and settled on 14
Sq. m. per person > could be reduced to 10 Sq. m. if food preparation and laundering
were communal

Le Corbusier in his book “The Urbanism” stated that there would be no more congested
streets, sidewalks, bustling public space, no more dirty neighbourhood. The people
would live in healthy and well regimented high-rise skyscrapers.

This rational city would be separated into discrete zones for working, living and leisure.

Examples: Planning of La Ville Radieuse, Ville Contemporaine, City of Chandigarh
City of Chandigarh

Initially, Plan was prepared by American Architect Albert Mayer and Mathew Nowicki

Later on, it was planned and designed by Le Corbusier.
City of Chandigarh
Le Corbusier conceived the master plan of Chandigarh as analogous to human body
 Head (the Capitol Complex, Sector 1),
 Heart (the City Centre Sector-17),
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 Lungs (the leisure valley, innumerable open spaces and sector greens),
 Brain (the cultural and educational institutions),
 Circulatory system (the network of roads, the 7Vs) and
 Intestines (the Industrial Area).
Some Features of Chandigarh Planning done by Le Corbusier

The shape of the city was changed from a leaf to a rectangle

Planned on a rigid rectangular grid iron pattern of roads

Used modular system, module of 800m X 1200m

envisioned for the 5 lakh (0.5 million) inhabitants

Planned in various sectors, each having human contents varying in numbers

Sectors are separated by fast moving traffic arteries known as V2 and V3 and
connected with a central green flowing from south to north in the direction of great
mountains.

The entire network of sectors was woven with a so called efficient system of traffic and
transportation governed by the rule of 7 Vs, changed by adding V8 to suit the specific
needs of the city

The industrial area was placed on the south-east of the city to eliminate any possibility
of heavy traffic entering the city

A 500 feet wide green belt provided an organic green to seal the residential sectors from
industrial fumes and noise.

Promoting Garden city concept
V8 Added later, Cycle track through
green spaces
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