Transcript 2 Unit 13 (Urban Structure Models)

MODELS OF
URBAN
STRUCTURE
GROUNDING
People are not randomly distributed in an urban
area. Instead, they concentrate in particular
neighborhoods by social characteristics.
Geographers have developed three models to
explain where different types of people will live in
urban areas:
THE CONCENTRIC ZONE MODEL
THE SECTOR MODEL
THE MULTIPLE NUCLEI MODEL
The models were developed based on Chicago (a
very flat city on a fairly uniform prairie, and then
adapted to other cities.
CONCENTRIC
ZONE MODEL
(THE BURGESS MODEL)
HISTORY
The model was
developed by EW
Burgess in 1923,
and is VERY
SIMILAR to VON
THUNEN’S
MODEL for
agricultural land
use from chapter
10.
THE MODEL
A city grows outwards in concentric rings from a central area (the size and width of the ring varies by city).
There are five rings:
1. CBD: nonresidential activities concentrate here
2. Zone in Transition: industry, poor quality housing, immigrants living in subdivided apartments, rooming houses for singles
3. Zone of Independent Workers Homes: working-class homes (modest, older homes with stable, working-class families)
4. Zone of better residences: newer, more spacious homes for middle-class families
5. Commuter’s Zone: small villages that are dormitory towns for some CBD workers
BURGESS AND
VON THUNEN’s
MODELS
BURGESS
Model describes urban/city land use relative to the CBD
VON THUNEN
Model describes agricultural/rural land use relative to the settlement
Both Models assume:
--land of uniform character and features
--the importance of centrality/accessibility to the market
--that individuals will maximize profit/land use and minimize costs
--that transportation costs are uniformly proportional to distance in all directions
--A single market
Location affects land use:
1. Intensive land use near CBD because of the high cost of rent
2. Intensity/density of residential land use decreases with distance from CBD
because households and other land uses locate further from CBD and can
afford transportation
3. High socioeconomic class at periphery because families can afford larger
homes/acreage/transportation
Location affects land use:
1. Intensive land use near market because farmers need high profits to pay
rent
2. Wood and perishable products near the market because they need
frequent/brief transportation to market
3. Extensive agriculture at the periphery because of the low land rent,
transportation costs and less perishable food products
SECTOR
MODEL
(THE HOYT MODEL)
HISTORY
The model
was
developed
by HOMER
HOYT in
1939.
THE MODEL
A city develops in a series of sectors because certain areas of the city are more
attractive for certain activities.
As the city develops, the activity expands outwards in a wedge (sector) from the
center as new facilities for that activity are added to the outer edge of the original
sector.
The Model also has five types of sectors (see above).
MULTIPLE
NUCLEI
MODEL
(THE HARRIS-ULLMAN MODEL)
HISTORY
The model was
developed by CD
HARRIS and EL
ULLMAN in 1939.
THE MODEL
A city is a complex
structure that includes
more than one center
around which activities
revolve (ex: a port,
neighborhood business
center, airport, park,
university, etc.)
A given node is a pull for
some activity but a push
for another. For example,
high-income housing will
not be pulled by an
industrial node.
APPLYING
THE MODELS
Urban structure models explain both where and why people with given social characteristics live in an urban area.
Effective application of the models depends on getting good data on the scale on individual neighborhoods
Good demographic data comes from taking a census.
The US census bureau breaks urban areas into CENSUS TRACTS where each tract will comprise about 5000 people and correspond (if
possible) to neighborhood boundaries. Chattanooga Census Tract
Map
The census collects data on dozens of demographic characteristics which can then be plotted on a map to show the distributions (and
patterns) of various characteristics over space. (See Every City, Every Block)
Taken separately, none of the
models are adequate
explanations for contemporary
urban patterns.
However, when combined, they
can begin to create an accurate
picture of settlement.
EX: Two families of same
income and ethnicity, but one
owns and one rents. What
would CZM predict?
Two families who own their
own home but have different
incomes. What would SM
predict?
CONCENTRIC ZONE
1. CBD
2. Zone in Transition
3. Zone of Ind. Workers Homes
4. Zone of better residences
5. Commuter’s Zone
SECTOR
1. CBD
2. Transportation and Industry
3. Low-class residential
4. Middle-class residential
5. High-class residential
MULTIPLE NUCLEI
1. CBD
2. Wholesale, light manufacturing
3. Low- 4. Medium- 5. High- (Class Residential)
6. Heavy Manufacturing 7. Outlying BD
8. Residential- 9. Industrial- (Suburb)
APPLYING
THE MODELS
Dallas: PERCENTAGE OF HOME OWNERS
Dallas: HIGH-INCOME HOUSEHOLDS
Dallas: DISTRIBUTION OF MINORITIES
As the concentric Zone model predicts, the
percentage of owner-occupied homes is
greater in outer rings of the city.
As the sector model predicts, the highestincome homes extend in a single sector to the
north of the CBD
As the multiple nuclei model predicts, African
Americans and Hispanics mostly occupy
separate nodes to the south and west of the
CBD respectively.
EUROPEAN
CITIES
American urban areas differ from those in other countries (both MDCs and LDCs) around the world.
The differences do not invalidate the models but show that social groups have different reasons for choosing their neighborhoods in another culture.
DISTINCTIONS
Wealthy Europeans still live in inner rings of the
upper-class sector, not just in suburbs (access to
shops and restored, historic residence)
Low-income Europeans are FAR LESS likely to live in
inner-city neighborhoods and more likely to live in
suburbs (longer commutes, poorer schools-shopsservices, higher levels of crime-violence-drugs, no
yards)
Ethnic minorities are clustered in suburbs
European officials encouraged construction of highdensity suburbs to preserve greenspaces and to
minimize sprawl
SIMILARITIES
Wealthy Europeans do cluster in a single sector
extending from the CBD (usually high ground and
near palaces)
LESS
DEVELOPED
COUNTRIES
European colonial policies left a heavy mark on the development of many LDC cities.
For example, the poor are concentrated in suburbs, and wealthy families live near city centers and in a sector extending from the center.
Many LDC cities have passed through three stages of development:
PRE-COLONIAL CITIES
Few cities existed in Africa, Asia and Latin America
before Europeans established colonies (most lived
in rural settlements).
Many cities were built surrounding a religious core.
Latin America: Mexico and Andean Highlands
Africa: Nile Valley, Islamic Empires in North & East
Asia: South and East (esp. India, China, Japan)
TENOCHTITLAN appears at right
FEZ, Morocco
ISLAMIC CITIES
--Centers were religious and marketplaces
--Gov buildings/wealthy homes surrounded center
--Lower wealth/status families farther from core
--recent immigrants on outskirts
--Commerce in concentric, hierarchical pattern
COLONIAL CITIES
CITIES SINCE INDEPENDENCE
As Europeans gained control of colonies, they
expanded existing cities to provide colonial
services.
Since independence, as LDC cities begin to
industrialize, millions of people have flocked to
cities looking for work.
The pre-existing city was either:
A) demolished (the Spanish destroyed
Tenochtitlan in 1521 and built Mexico City) OR
B) left to one side with the expansion happening
in a new area (the French in Morocco, the
British in New Delhi).
Wealthy families push out from center in a welldefined sector on either spine of a high-end
service sector
SQUATTER
SETTLEMENTS
LDC cities are unable to house the rapidly growing number of urban
poor.
Most poor immigrants to urban areas live in SQUATTER SETTLEMENTS
(large, unplanned neighborhoods on the outskirts of LDC cities… aka
favelas [Latin America], bidonvilles [North Africa], bastees [India],
gecekondu [Turkey], kampongs [Malaysia], barong-barong
[Phillippines].
RIO DE JANEIRO
WHY THEY FORM
--Large scale rural to urban migration (looking for jobs)
--Poor citizens who cannot afford planned housing
--Lack of enough housing (public and private)
--Lack of (failure to enforce) land use policy
LOCATION
-- On edge/periphery of the city.
--On otherwise unusable/undersirable land (ravines, gullies,
hillsides, floodplains, landfills, cemeteries, industrial zones)
--On Land with an unclear title
CHARACTERISTICS
--Unplanned streets and shelters/homes are constructed of scrap
--Have few to no services
--Lack schools, paved roads, telephones, sewers, running water
--SOME have high levels of violence
Video on Rocinha in Brazil
CONSEQUENCES
--Unhealthy conditions lead to high morbidity and mortality
--Increase in crime
--Development of gangs or other extralegal authority systems
--Development of political action/unrest
--Increased water pollution due to lack of sanitation and garbage removal
--Increased soil erosion on hillsides and deforestation
--Decreased air quality from wood fires for heating and cooking
--Increase in availability of cheap labor
--Increased risk of disasters(fires, industrial accidents, mudslides, flooding)
--Strain on infrastructure with burden on tax payers
SQUATTER
SETTLEMENTS
Favelas in Rio de Janeiro, Brazil
SQUATTER
SETTLEMENTS
AND SUBURBS
Both squatter settlements and suburbs reflect growth of urban areas (URBANIZATION).
Both are a type of SPRAWL (the unplanned extension of urban land uses into rural areas). (CNN Sprawl site)
REGIONS
DEFINING CHARACTERISTICS
REASONS
DEMOGRAPHIC TRANSITION
--Suburbs in MDCs and more developed pockets of some LDCs.
--Suburbs are planned developments. They are added to the outer edge of settlements (usually on
prime land). They are equipped with a full range of public and consumer services. They are occupied by
higher income families. The residents are often more established/longterm residents.
-- Wealthy urban dwellers leave the inner parts of the city, or first ring suburbs, in order to have more
open space, larger homes, or easier access to employment outside the center.
-- As countries enter stage 3 of the DT, residents who have gained sufficient wealth engage in
intraregional migration at the scale of cities moving from central city neighborhoods to suburban areas.
--Squatter Settlements in LDCs
--Squatter settlements are unplanned developments. They are added to the outer edge of settlements
(usually on unused/unwanted land). They have no public services and few consumer services. They are
occupied by the lowest income families. The residents are often recent immigrants to the area.
--Poor people from the countryside move to the city but, unable to afford homes in the center, establish
themselves on the periphery. Eventually, they will seek services from the city and have roads, schools, etc.
--As countries enter stage 2 of the DT and begin to industrialize, farmers from rural areas move to cities
seeking factory work, OR jobless people from stage 2 countries migrate to economic centers of stage 3
countries (often to primate cities) to seek jobs.