Comparative Models of Urban Systems

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Comparative Models of Urban Systems
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Purpose of Urban Models

• To understand why cities are spatially organized
  in various ways, geographers have developed
  models that explain and predict the internal
  structures of cities.
• Most focus on patterns of internal growth in U.S.
  cities.

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Central Business District

• Land use models possess a CBD.
• Central Business District Original core of the
  economy, like the nucleus of a cell.
• The degree of influence and geographic location
  of the CBD varies model to model.

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• Developed in the 1920s the concentric zone model
  was the first model to explain and predict urban
  growth.
• Based on growth in Chicago
• Developed by Ernest Burgess
• Zones
• 1. CBD
• 2. Light manufacturing
• 3. Blue Collar Workers
• 4. Middle Class
• 5. Suburban Ring
• Dynamic city grows inner rings affect outer ones

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Invasion and Succession

• The Concentric Zone model assumes a process
  called invasion and succession (succession
  migration)
• A series of migration waves, with one group
  moving in and establishing itself.
• New arrivals to cities tend to move first into
  the inner rings, near the CBD.
• Eventually people and economic activities in the
  center are pushed out into farther rings

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• Homer Hoyt (1939) criticized Burgess Model as
  too simple inaccurate
• Urban land use and growth are based on
  transportation routes and linear features like
  roads, canals, railroads, and major boulevards.
• Not just concentric zones around the CBD.
• Still has strong CBD
• According to this model-
• Many factories and industrial activities follow
  rail lines.
• Lower socioeconomic housing follows lines of
  public transportation.
• Sectors that service visitors are located along
  major highways.
• ITS ALL ABOUT TRANSPORTATION

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• Multiple Nuclei Model
• Chauncy Harris Edward Ullman (1945) neither of
  previous two models are accurate
• CBD not as significant
• Suggest growth occurred independently around
  several major focal points.
• Separate nuclei become specialized and
  differentiated, not located in relation to any
  distance attribute

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• Developed to explain suburban regions that were
  functionally tied to mixed-use suburban downtowns
  with relative independence from the CBD.
• Suburban downtowns have become independent
  functioning urban realms
• All the amenities needed for living are now
  located in the suburban downtown.

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Edge Cities

• Self-Sufficient urban areas within a greater
  metropolitan complex.
• Often develops on highway exits.
• The development of edge cities paired with the
  growth of highways leads to explosive industrial
  growth referred to as urban sprawl.
• Urban sprawl.the diffusion of urban land use and
  lifestyle into formerly nonurban, often
  agricultural lands.

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Urban Realms (and Edge Cities) of Los Angeles
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Writing Prompt

• In your journals respond to the following.
• Can you see evidence of urban sprawl in Arizona?
• How does urban sprawl impact the
  existence/importance of the Central Business
  District?