THE URBAN SYSTEM

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THE URBAN SYSTEM

• CENTRAL PLACE THEORY and RELATED CONCEPTS

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The US at night
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Is there an order to this?
Maybe its an underlying geometry in the
settlement pattern
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Is there an order to this?
Maybe all we need to do is rearrange the cities
slightly to make the pattern apparent.
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OBJECTIVE

• to understand the dynamics shaping the urban
  hierarchy
• what makes cities grow quickly or slowly?
• how do urban settlements of a particular size
  affect the emergence and growth of other
  settlements of the same or different size?
• what pattern would the system of settlements form
  in the absence of complicating factors such as
  topography and history?

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Why ask these questions?

• to advance toward a more scientific understanding
  of urbanization
• to develop a foundation on which to build a
  positivist theory of urban growth
• to raise urban studies to the level of the
  hard sciences--assuming the hard sciences are
  superior to the soft (humanistic, descriptive,
  probabilistic) sciences

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Every science needs a force

• economic competition
• between cities
• rational maximization
• by individuals
• friction of distance as a driving force
• cost distance
• time distance
• (later) cognitive distance

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In short

• Through rationally maximizing the productivity of
  their time
• by minimizing the costs of various activities
  measured in money and time,
• people collectively create a system in which
  facilities of all sorts
• including cities,
• are pitted against each other
• and all facilities emerge from this competition
  in advantageous locations and with
  predictable-sized areas of dominance.

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Competition Produces Order

• In other words

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Founders of Central Place Theory

• C.J. Galpin (1915)
• sociologist studying rural communities in
  Wisconsin
• decided that under ideal conditions settlements
  would be spaced evenly
• pattern overlapping circular service areas with
  the central places aligned in a hexagonal array
• overlap of service areas indicates a region in
  which a person is equally inclined to shop at
  either central place

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Galpins model
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Founders of Central Place Theory

• Walter Christaller (1966)
• assumption each good has its particular range
  and threshold
• threshold of a good minimum size of market
  capable of sustaining a business devoted to that
  good
• range of a good maximum distance a person will
  be willing to travel to obtain that good
• associated assumptions
• variations in range and threshold from person to
  person or from culture group to culture group are
  irrelevant
• most people will shop at only one center

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Details of Christallers theory

• The vast range of retail functions could be
  grouped into 7 orders, corresponding to cities
  with different sized hinterlands
• the functions in an order share a similar
  threshold and range
• automobiles would be in a different order than
  loaves of bread, for example
• What might be in the same order as automobiles?
• What might be in the same order as loaves of
  bread?

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Hypothetical pattern of central places
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More terminology

• Higher order goods and services are those with
  a wider range and higher threshold, located in
  larger urban centers
• Lower order goods and services are those with a
  narrower range and lower threshold, located in
  smaller urban centers
• break point the invisible boundary between
  markets of competing central places
• isotropic plain uniform land surface on which
  these ordering principles would generate a
  hexagonal pattern of cities

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An interpretation of the urban hierarchy (listed
by order)

1. largest cities (all functions, highest to lowest)
2. large cities
3. small cities
4. larger towns
5. smaller towns
6. villages
7. hamlets (only the lowest order functions)

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Variations on the basic theory

• different patterns result from different values
  of k
• market optimizing, k3 (minimizes total number of
  settlements serving a region)
• traffic optimizing, k4 (emerges by minimizing
  the road lengths joining all adjacent centers)
• administration optimizing, k7 (assumes
  lower-order places must be contained in the
  administrative districts of higher order places
  can not be situated on the breakpoint)

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Market principle (a) and transportation principle
(b)
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Market principle Transport
principle Administrative principle
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The US at night
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Cool idea, not much basis in reality

• cities just dont form these patterns
• they do respond to some kind of hierarchy-forming
  process, however
• evidence
• the rank-size distribution
• alternative explanation
• connection rather than competition the power
  function law of networks

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Founders of Central Place Theory

• August Lösch (1954)
• similar to Christallers theory but without the
  classification of urban functions into a finite
  number of orders
• implication was that cities could be any size and
  would form a continuous distribution of sizes

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Power laws and scale-free networks
Recent research on networks of various types
(Internet, neural networks, social networks,
electrical grid, ecological systems,
biochemicals, brains) has revealed that the
hierarchy of node degree consistently follows a
power law relationship straight line on a
log-log graph.
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What would this indicate?

• Urban hierarchys regularity may not be caused by
  the random perturbation of what would ideally be
  a step-wise function caused by competition
  between cities
• Instead, it may be caused by the natural
  emergence of dominant (hub) nodes within a
  dynamic network