urbanization models. comparative models of north american cities the central business district...
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Urbanization Models
Comparative Models of North American Cities
The Central Business District◦ Definition:
CBD- original core of a city’s economy, like a nucleus of a cell
CBD is compact, less than 1% of urban land area◦ But contains a large % of
shops, offices, and public institutions
◦ Consumer services and business services are attracted to the CBD because of its accessibility Center is easiest part of city to
reach from the rest of the region◦ Focal point of region’s
transportation network
Characteristics of a CBD◦ High land costs
Discourages Industry in the CBD
◦ Intensive land use Skyscrapers
All of the following models possess a central business district◦ Degree of influence and
geographic location of CBD varies throughout different models
Comparative Models of North American Cities
Concentric Zone Model
Also called the Burgess model◦ Developed in 1920’s by E.W.
Burgess◦ 1st model to explain and predict
urban growth All other urban models are built
on this model
Based on urban growth in Chicago
Model suggests that a city’s land use can be viewed from above as a series of concentric rings◦ As the city grows and expands,
new rings are added and older rings change their function
◦ Size and shape of rings vary per city
Comparative Models of North American Cities
The five rings:◦ 1- CBD
innermost ring where non-residential activities are located
◦ 2- Zone of transition Contains industry and poorer-
quality housing Immigrants to city often 1st live
here◦ 3- Zone of working-class homes
Modest, older homes occupied by stable, working-class families
◦ 4- Zone of better residences Contains newer and more
spacious houses for middle-class families
◦ 5- Commuter Zones Beyond the continuous built-up
area of the city
Concentric Zone Model
The model assumes a process sometimes called invasion and succession (or succession migration)◦ Definition:
New arrivals to cities 1st tend to move to the inner rings near the CBD
This pushes the people and economic activities already present out into further rings
This constant pattern can lead to a ring known as the zone in transition◦ Definition:
Zone outside CBD Never really developed
◦ Developers know that it will be constantly caught in shift Sometimes called “skid-row”
In model, the CBD is the premiere land-use ring nearest the point of maximum accessibility◦ Called peak land
value intersection Highest real estate
prices Land values decrease
as you move away from CBD◦ Furthest ring the
cheapest
Bid-Rent Curve
Bid-Rent curve predicts the land prices and population density decline as distance from the CBD increases
Bid-rent curves show the variations in rent different users pay for land at different distances from some peak point of accessibility and visibility in the market◦ Usually the CBD
Transportation costs increase as you move away from the market◦ Rents usually decrease as
distance increases from the market
Bid-Rent Curve
Different types of land use generate different bid-rent curve◦ Ex: commercial retail,
industrial, agriculture, housing
Bid-rent curves explain the series of concentric rings of land use found in the concentric zone model
Model shows a pattern in which architectural form and function of buildings match in each concentric ring and urban land use
Sector Land Use Model
Sector Model was developed by Homer Hoyt in 1939◦ Discovered a twist on the
concentric zone pattern According to Hoyt, the city
develops in a series of sectors, not rings
Also based off of Chicago
Model grew out of observations that there were urban land-use zones of growth based on transportation routes and linear features ◦ roads, canals, railroads, major
boulevards◦ Not just concentric zones
around the CBD
Sector Land Use Model
The Sector Model explained that similar land uses and socioeconomic groups clumped together in geometric sectors
Certain areas of the city are more attractive for various activities
◦ Sectors radiated out from CBD along particular transportation routes Ex:
◦ Many factories follow rail lines, housing followed public transportation, visitor services along major highways
Multiple-Nuclei Land Use Model
New Model of urban growth discovered in 1945◦ Chauncy Harris and Edward Ullman
Unlike previous models that focused on a strong CBD, this model suggested that growth occurred independently around several major focal points◦ A.K.A. a city is a complex structure
that includes more than one center around which activities revolve Ex: airports, universities, highway
interchanges, ports
Focal points may be distant from “original” CBD and only loosely connected◦ Suggesting a reduced dominance
of the CBD
Multiple-Nuclei Land Use Model
The multiple nuclei model reorganized that land use zones often popped up at one, in chunks◦ Industrial parks, shopping
centers, and housing zones could be built in one, giant sweep of construction and be only very loosely connected to the original heart of the city
The model does not suggest the CBD is not necessarily unimportant◦ but does show that new areas
of intense, urban growth (called nuclei) can grow simultaneously around key nodes of access or industry
Some activities are attracted to particular nodes, whereas other try to avoid them◦ Example:
A university node might attract pizza places and bookstores
Apply the Models
The three models help to understand where people with different social characteristics tend to live within an urban area
Can also help explain why certain types of people live in particular places◦ Uses social area analysis
Uses census information to compare characteristics
None of the models individually explain why different types of people live in distinctive parts of the city◦ When combined, more helpful
Critics◦ Models are too simple ◦ Fail to consider the variety of
reasons that lead people to select particular residential locations
◦ All three models created between WWI/ WWII No longer relevant
The models say that most people prefer to live near others who have similar characteristics◦ Concentric Zone
Consider two families with the same income and ethnic background
One family owns a home, the other rents
The owner would more likely live in an outer ring and the renter in the inner ring
◦ Sector Model Given two families who own
homes, the family with the higher income will not live in the same sector of the city as the family with the lower income
◦ Multiple Nuclei People with the same ethnic or
racial background are likely to live near each other
Urban Realms Urban Land Model
Developed by James Vance in 1960s◦ Influenced by increasing importance of
automobile◦ Explained suburban regions that were
functionally tied to mixed-use, suburban downtowns with relative independence from the CBD Developed while observing the San
Francisco Bay area metropolis
Model grew from the multiple-nuclei model
Argued nuclei were not just focal points of urban growth but developing into functioning “urban realms”
Urban realms model recognized that many people’s daily lives and activities occurred within a fixed activity space within a portion , or urban realm, of a larger metro region◦ In these “urban realms” on could find
suburban downtowns filled with amenities needed for living
◦ “urban realms”
Borchert Model of Urban Evolution
In the 1960’s, Samuel Borchert studied cities in the United States and linked historical changes to urban evolution◦ Borchert’s model
defined four classical of cities based on the transportation technology that dominated the era when the city hit its initial growth spurt and found it’s comparative advantage
Classifications◦ Stage 1
Hit growth spurt in “sail-wagon” era of 1730-1830
Mostly near ports and waterways for transportation
◦ Stage 2 “iron-horse” cities Grew around rivers and
canals between 1830-1870 when railroads and steamboats were growing rapidly
◦ Stage 3 “steel-rail epoch” 1870-1920 During IR, when steel
industry blossomed◦ Stage 4
1920 Linked to air and car travel
European Cities
In contrast to U.S. cities, wealthy Europeans still live in inner rings of the upper-class sector◦ Not just in the suburbs
As in the U.S. wealthier Europeans cluster along a sector extending out from the CBD◦ Often away from factories, on
higher elevations
Before electricity social segregation was vertical◦ Meaning poor people lived in the
basements or attics of buildings
Today lower income families live outside the inner-city◦ Mainly outskirts
Latin American Cities
Latin American City Structure Model◦ Also called Ford-Griffin Model
Created by Larry Ford and Ernest Griffin◦ Particularly focused on areas colonized
by Spain
Stages of Latin American cities◦ Pre-colonial
Very few cities, ex. Tenochtitlan Most lived in rural settlements
◦ Colonial Expanded existing cities Followed standardized plans
◦ 1400s- Renaissance saw rebirth of Greco-Roman architecture and planned cities
◦ 1573- Spain passed a law ordering all colonial cities be built according to Greco-Roman designs Prominent, rectangular plazas
dominated by Catholic Church and major governmental buildings
◦ Since independence Changing rapidly
Latin American City Structure Model
Commercial and residential zones encircled the Latin American plaza◦ Similar to CBD in North
American cities◦ CBD was most important in
the focus of Latin America Suburbanization weaker
In a Latin American city, wealth typically decreases as one moves outward from the downtown area◦ Typically squatter settlements
and rings of poverty are found in rings outside of the CBD Zones of squatter settlements
are called Perifericos
Other zones Zone of in situ
accretion◦ A region
transitioning towards maturity and development that is a mix of middle-income and lower-income families
Zone of maturity◦ Includes services
and infrastructural development
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