Hgap 6.4

Learning Goals

• 47-1 Describe an urban system.

• 47-2 Explain the rank-size rule and primate city rule to elucidate the urban hierarchy.

• 47-3 Describe central place theory.

• 47-4 Describe the gravity model.

Urban Systems

Definition of Urban System

• An urban system consists of interdependent cities connected by networks.

• Interdependencies: Urban places exchange goods, services, ideas, money, and labor.

• Structure: Typically includes towns and cities and their hinterlands within a national or regional context.

Examination of Urban Systems

• Washington Example: A map of Washington state reveals variations in urban systems.

• Eastern vs. Western Washington:

  • Western: Major urban centers (Seattle, Tacoma) connected by interstates (I-5, I-90).

  • Eastern: Urban systems are different, smaller cities (Spokane) surrounded by agricultural land.

  • Urban Hierarchy: Differentiation in size and services based on geographical location.

Key Cities in Washington

• 500,000+: Seattle, Portland.

• 100,000 to 499,999: Tacoma, Bellevue, Everett, Spokane.

• 25,000 to 99,000: Cities like Bellingham, Yakima, and others.

Rank-Size Rule and Primate City Rule

Urban Hierarchy

• Urban hierarchy ranks cities based on size and power.

• Rank-Size Rule: The population of a settlement is inversely proportional to its rank.

  • E.g., City #2 has half the population of City #1, City #3 has one-third, etc.

• Primate City Rule: A system where the largest city has more than double the population of the second largest city.

Application of Rules

• Examples based on U.S. cities show how the rank-size rule is often more applicable in developed nations.

• Example:

  • New York City (8.17 million), Los Angeles (3.79 million), Chicago (2.70 million).

  • Major cities show a loose correlation with rank-size tendency, generally more developed countries.

• Primate cities:

  • Lagos (8 million) dominates Nigeria, with Kano significantly smaller.

  • London, Moscow also exemplify occurrences of primate cities.

Central Place Theory

Definition and Origin

• Developed by Walter Christaller in 1933, aims to explain the organization of cities and their roles as economic centers.

• Assumptions: 5 fundamental premises about geography, population distribution, and service accessibility.

Practical Implications

• Low-order Goods: Require less distance to acquire (e.g., groceries).

• High-order Goods: More specialized, require longer travel distances (e.g., art exhibitions).

• Settlement Hierarchy: Illustrated using hexagons, showing spatial relationships between urban and rural places.

Modern Relevance

• Central Place Theory offers insight but does not fully apply to modern urban scenarios.

• Population distribution and service access vary; theory reflects old assumptions against modern urban patterns.

Gravity Model

Overview

• Mathematical model predicting interaction between two places based on population and distance.

• Formula: Interaction = (Population1 × Population2) / Distance²

• Conclusion: Closer places interact more but interaction diminishes with distance.

Applications of the Gravity Model

• Used by urban planners to study migration and transportation systems.

• Exemplified in the relation between New York City and nearby regions like New Jersey.

Critique

• Some argue its predictive capability is limited in modern contexts.

• Distance no longer crucial for transactions with advancements in technology (e.g., online services).

Conclusion

• Understanding urban landscapes involves exploring various interconnected theories and models.

• Although not perfect predictions, these models help illuminate urban organization and development.