Third World Urbanization by gjjur4356

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									Urbanization of LDC’s
Urban Land Use Models
      Ken Keller
      DHS - 2004
                Introduction
• Urbanization = % of population living in
  cities
  –   1950 -- 16%;
  –   1985 -- 30%;
  –   1995 -- 43%;
  –   2000 -- 47%
World’s Population is now
predominantly urban - 2005.
          Growth in BIG cities
• > 1 million       • > 4 million
   – 31 in 1950        – 5 in 1950
   – 146 in 1985       – 28 in 1985
   – 486 in 2025       – 114 in 2025




  Very large cities are a feature
  of LDCs -- 17 of 23
  megacities are in LDCs
World Megacities
Cycle of Urbanization
         Cycle of Urbanization
• Stage 1 – Initial Stage: agrarian society, little
  surplus of production
• Stage 2 – Acceleration Stage: beginnings of
  development, growth is concentrated in cities,
  rural-to-urban migration
• Stage 3 – Terminal Stage: advanced stages of
  development, urbanization levels off with service
  economy and communications technology
         Urban Growth Processes
• Rise of urbanization today follows beginning of s-
  shaped curve, but the ABSOLUTE
  INGREDIENTS ARE MUCH LARGER. It
  took NYC 150 years to gain 8 million people.
  1980 - 2000 growth:
   –   Dhaka -- 8 million      Lagos -- 9 million
   –   Bombay -- 10 million    Karachi -- 7 million
   –   Delhi -- 6 million      Manila -- 6 1/2 mil.
   –   Jakarta -- 7 million
    Urban Growth Processes, cont.
•   Lower levels of development
•   Higher population growth
•   No migration escape hatch
•   Future urbanization in Asia and Africa
      Sources of urban growth
• Natural Increase accounts for 60% of growth.
   – High population growth rates
   – Young populations
• Boundary changes and reclassification account for
  8-15% of growth
• Rural-to-urban migration accounts for 25-32% of
  growth. Many LDCs are already highly
  urbanized.
• At low levels of urbanization, urban growth comes
  from migration, later from natural increase.
      • Africa = 33%; Latin America = 75%; Asia = 38%
            3 critical issues
• Overurbanization: Has urbanization
  outstripped the economic capacity to supply
  urban jobs?
• Cost/benefits? Do the costs of large-scale
  concentration outweigh the benefits?
• Primacy? Do megacities dominate the
  urban system at the expense of mid-size
  regional centers?
            Overurbanization?
• Urbanization has always accompanied
  development and modernization. The pace of
  urbanization is surpassing the creation of new
  urban jobs.
• The informal sector accounts for 1/3 to 1/2 of all
  employment in Third World cities.
   – Formal vs. informal sector
   – Why do people move to cities where there are not
     enough formal-sector jobs?
         Costs vs. Benefits of
           Concentration
• Pros
  – Megacities allow country to concentrate its
    meager resources.
  – Megacities contribute disproportionately to the
    national income. Shanghai produces 11% of
    China’s industrial output and supplies 18% of
    its gov’t revenue; Lagos produces 50% of
    Nigeria’s manufactured goods; Mexico City
    produces 1/3 of Mexico’s GNP.
  – Huge markets -- economies of scale
  – Megacities offer a wide range of goods and
    services; they are a desired business location.
• Cons
  –   Inadequate water supply and sewage disposal
  –   Poor air and water quality
  –   Congestion and transportation problems
  –   Political unrest -- “haves” vs. “have-nots.”
  –   Inadequate housing -- 1/5 to 1/2 live in
      “informal shelters.”
             Urban primacy
• When one city dominates the urban system.
  This is not the case in the US where NY,
  LA, and Chicago sit at top, followed by
  regional centers of Atlanta, Boston,
  Philadelphia, Seattle, Denver, and Phoenix,
  followed in turn by smaller cities and small
  towns and rural areas.
• Many LDCs have urban systems that
  consist of the megacity and then much
  smaller towns. Consequences of missing
  regional centers.
        Examples of Countries With Primate Cities:

Paris (2.2 million) is definitely the focus of France while
Marseilles has a population of 800,000.
Similarly, the United Kingdom has London as its primate
city (6.9 million) while the second largest city, Birmingham,
is home to a mere one million people.
Mexico City, Mexico (9.8 million in the city; 16.6 million in
the metropolitan area) outshines Guadalajara (1.7 million).
A huge dichotomy exists between Bangkok (5.9 million) and
Thailand's second city, Nakhon Ratchasima (278,000).
            Examples of Countries that Lack Primate Cities:

India's most populous city is Mumbai (formerly Bombay) with 9.9
million; second is Dehli with 7 million, third is Kolkata (formerly
Calcutta) with 4.4 million, and fourth is Chennai (formerly Madras)
with 3.8 million.
China, Canada, Australia, and Brazil are additional examples of non-
primate-city countries.
Utilizing the metropolitan area population of urban areas in the United
States, we find that the U.S. lacks a true primate city. With the New
York City metropolitan area population at approximately 20.1 million,
second ranked Los Angeles at 15.8 million, and even third ranked
Chicago at 8.8 million, America lacks a primate city.
                 Rank Size Rule
• In 1949, George Zipf devised his theory of rank-size rule
  to explain the size cities in a country. He explained that the
  second and subsequently smaller cities should represent a
  proportion of the largest city. For example, if the largest
  city in a country contained one million citizens, Zipf stated
  that the second city would contain 1/2 as many as the first,
  or 500,000. The third would contain 1/3 or 333,333, the
  fourth would house 1/4 or 250,000, and so on, with the
  rank of the city representing the denominator in the
  fraction.
• While some countries' urban hierarchy somewhat fits into
  Zipf's scheme, later geographers argued that his model
  should be seen as a probability model and that deviations
  are to be expected.
Firms and household compete for space in a way that maximizes satisfaction, within
budget constraints, for every actor. Resulting in maximizing the “efficiency” of the
urban space economy.
Several assumptions to the model:
City is on a flat, featureless plain
Transport is ubiquitous; costs are only a function of distance
City has a CBD is in the geographic center of the city
Inhabitants are all “economic men”
Above assumptions all imply an unstated one: Perfect competition
Bid-rent theory:
For all types of land uses, the most central sites will be the most attractive
Given total space available in the city, the central sites are relatively few, so competition
for them will be intense, and prices higher
Different types of land users will place different financial evaluations on the utility of
centrality.
Each type of land user will have a different and distinct bid-rent curve that reflects the
prices that type of users is prepared or able to pay for sites at different distances from
the CBD.
Putting the bid-rent curves together, we can see the overall bid-rent model shows that
users with the steepest curves will capture the more central sites, while those with
shallower curves --such as residences-- are left with more peripheral sites.
Those with higher incomes will have steeper bid-rent curves and so end
up nearer to the city center, while the lowest-income groups will end up
on the periphery.
 Different households will bid for different-sized lots in different
locations according to their relative preferences for living space versus
the utility of accessibility. A trade-off between living space and
commuting costs. Bid-rent model is also called the trade-off model.
                                       Land use is thus determined by the
                                       rent-paying ability of different
                                       economic functions in urban areas,
                                       such as retailing, industry and
                                       residence. The optimal location,
                                       where accessibility is optimal, is the
                                       central business district. All
                                       activities, including rural, would like
                                       to be located there, but they do not
                                       have the same capacity to afford this
                                       optimal location.
Factors influencing the bid-rent curve:
•Zoning laws
•Different forms of transportation
•Local variations in taxes
•Cultural or regional preferences for housing type or tenure
•Geography/topography and its affect on landscape views, affects
of various industrial “run-offs”, e.g. being downriver or downwind.



Limitations of the Bid-rent approach
•Perfect competition may not exist
•People do not always act “rationally”
•Search for locations is constrained by time, money, imperfect
information, other players
•Land and property markets constrained by regulatory controls
•Special interest groups affect land use and access
      The Burgess (Concentric Zone)
      Urban Land Use Model

In 1925, E.W. Burgess presented an urban land use model,
which divided cities in a set of concentric circles expanding
from the downtown to the suburbs. This representation was built
from Burgess's observations of a number of American cities,
notably Chicago.
According to this model, a large city is divided in concentric
zones with a tendency of each inner zone to expand in the other
zone. Urban growth is thus a process of expansion and
reconversion of land uses.
   numerous criticisms:
The model is too simple and limited in historical and cultural
   applications up to the 1950s. It is a product of its time.
The model was developed when American cities were growing very fast
   in demographic terms and when individual transportation was still
   uncommon. Expansion thus involved reconversion of land uses. This
   concept cannot be applied in a contemporary context where highways
   have enabled urban development to escape the reconversion process
   and settle in the suburbs.
The model was developed for American cities and has limited
   applicability elsewhere. It has been demonstrated that pre-industrial
   cities, notably in Europe, did not at all followed the concentric circle
   model. For instance, in most pre-industrial cities, the center was
   much more important than the periphery, notably in terms of social
   status.
There were a lot of spatial differences in terms of ethnic, social and
   occupational status, while there were low occurrence of the
   functional differences in land use patterns. The concentric model
 Sector Model- Urban Land Use
 Representations



A study done in 1939 by Homer Hoyt concluded that the land
use pattern was not a random distribution, nor sharply defined
rectangular areas or concentric circles but rather sectors.
Communication axes are mainly responsible for the creation
of sectors, thus transport has directional effect on land
uses. We can see on the sector representation that Burgess
transitional process is still part of land use changes, but there
exist axes along which urban activities are oriented.
  Multiple Nuclei Model - Urban Land Use Representations



Following Hoyt’s development of a sectorial city, C.D. Harris and E.L.
Ullman (1945) introduced a more effective generalization of urban
land uses. It was brought forward that many towns and nearly all large
cities do not grow from around one CBD, but are formed by the
progressive integration of a number of separate nuclei in the urban
pattern. These nodes become specialized and differentiated in the
growth process and are not located in relation to any distance attribute,
but are bound by a number of attributes:
Differential accessibility. Some activities require specialized facilities
such as port and rail terminals. For instance, the retailing sector
demands maximum accessibility, which is often different from
centrality offered in the CBD.
 Multiple Nuclei Model - Urban Land Use Representations – Cont.

Land use compatibility. Similar activities group together since
proximity implies improved interactions. Service activities such as
banks, insurance companies, shops and institutions are strongly
interacting with each other. This can be defined as centripetal
forces between activities.
Land use incompatibility. Some activities are repelling each-
other such as high quality residential and heavy industrial. This
may be defined as centrifugal forces.
Location suitability. Some activities cannot afford the rent of the
optimal site for their location. They are thus locating at cheaper
places, which are not optimal, but suitable for these activities.
Harris and Ullman polynuclear model was the first to represent
the fragmentation of urban areas, specialised functions as well as
suburbanization.
Although the urban experience in
Latin America has varied because
of diverse historical, cultural, and
economic influences, there are
many common threads that have
prompted geographers to search for
useful generalizations. One is the
model of the intra-urban spatial
structure of the Latin American city
proposed by Ernst Griffin and
Larry Ford, which may have wider
application to cities of poor
countries in other geographic
regions as wells. The basic spatial
framework of city structure, which
blends traditional elements of Latin
American culture with
modernization forces now
reshaping the urban scene, is a
composite of radial sectors and
concentric zones.
            Breakdown of Latin American city model:

    The Central Business District is the city's hub. Here one finds the
  central plaza, the principal church, and government buildings left over
from colonial times, as well as the bulk of commercial activity, including
  high-rises, outdoor markets, hotels and restaurants. In the New model,
         the market is connected to the CBD, but distinct from it.
 The next zone is the Spine/Elite Residential Sector. This area contains
 all significant recreational and cultural activity not housed in the CBD.
    With easy access the CBD, this sector is also the first to obtain city
   services and utilities. It contains the city's most prestigious housing,
  occupied by the wealthy, or "filtered down" to the upper-middle class
  once the wealthy move to outlying areas. In the New model, this spine
  ends in a mall, a miniature business district of its own and a symbol of
                       the neighborhood's prosperity.
The Zone of Maturity is made up of large, solid homes, made of
brick or concrete. This zone's population tends to be older and
more established than the others', and socially middle or upper-
middle class. All city amenities are available here, and the sector is
regarded as a stable neighborhood. In the New model, a
Gentrification zone encroaches on the area. This sector borders,
both geographically and figuratively, between the elite and mature
zones, creating a space for the upwardly mobile.
Further out lies the Zone of In Situ Accretion. Of modest quality,
the homes in this area are constantly under construction. Their
owners improve the structures little by little according to their
economic mobility and the availability of city services. This is a
sector in constant transition.
In the periferico are the Squatter Settlements. This zone has the
worst housing conditions and fewest amenities in the city, with
little vegetation and often no running water or electricity. Recent
in-migrants to the city reside here in informal houses.
Disamenity zones are dumps or other unused/unusable land.
La Paz, Bolivia has grown to an enormous size, with sprawling shanty-
towns spreading up the sides of the valley to the rim of the Altiplano
Mountains. The city of 1.7 million is very much divided by class, with
a distinctly small urban elite, a forever expanding, poverty-stricken
lower class, and a newly emerging middle class. Over half of the
population is Indigenous.
                                           La Paz has one main boulevard
                                           that runs the length of the city,
                                           following the natural canyon
                                           made by the Choqueyapu River,
                                           diagonally from the Northwest to
                                           the Southeast. Away from the
                                           main drag, streets climb steeply
                                           uphill, and many are cobbled or
                                           unpaved. Above the downtown
                                           skyscrapers, the adobe
                                           neighborhoods and the informal
                                           market areas climb toward the
                                           canyon's rim.

								
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