Urbanization and Urban Models - Lecture Notes

The phenomenon of Megacities highlights the rapid urbanization trends across the continent.

Services: Origins and triggers for urbanization.
The relevance of Central Place Theory and Gravity Model in service distribution.
The difficulty of defining urban areas and their demographics in different contexts (MDC vs LDC).
The impact of primate cities on service distribution and the tendency for service clustering in downtown areas.

Description: CBDs are characterized by a low percentage of urban land area yet a high concentration of urban services.
Types of Services in CBDs:
1. Public Services: City administration, courts, libraries, and sports/convention centers.
2. Business Services: Advertising, banking, finance, and legal services that thrive on proximity to other businesses.
3. Consumer Services: Retailers with high thresholds, ranges, or those serving CBD workers. Trends show a decline in retail due to shifts to affluent suburbs.
3-Dimensional Nature of CBD: Vertical development is necessary due to land demand, creating underground spaces for utilities and high-rise buildings.
Bid-Rent Theory: Explains how land pricing changes with distance from the CBD, indicating the economic advantage of central locations.

City: An incorporated urban settlement that serves as a governing unit (e.g., central city in the U.S.).
Urban Area: Encompasses densely settled cores, suburbs, and linked low-density areas. Defined by the census as either urbanized (50,000+) or clusters (2,500-50,000).
Metropolitan Statistical Area (MSA): Includes urbanized areas, its county, and surrounding areas with economic ties, primarily work-related.
Micropolitan Statistical Area: Defined similarly but includes areas with a population of 10,000 to 50,000.

Core-Based Statistical Areas: These encompass various urban areas, illustrating growth patterns in metropolitan and micropolitan contexts.
Urban Sprawl: Characterized by unplanned chaotic growth around the edges of urban areas, leading to inner-ring suburbs formed before the 1970s and outer-ring suburbs developing later for larger, cheaper plots.
Boomburbs: Rapidly expanding suburban cities housing over 100,000 residents, often indicative of economic growth.

Major factors for urban expansion include legislation like the Interstate Highway Act, social mobility, and housing policies like the GI Bill post-WW2.

Concentric Zone Model: Proposed by E.W. Burgess in 1923, which posits that urban growth occurs in rings.
- Zones include a CBD, transition areas, working-class homes, middle-class residences, and commuter zones.
Sector Model: Coined by Homer Hoyt, suggesting urban areas develop along zones radiating from the CBD based on socio-economic status.
Multiple Nuclei Model: Developed by Harris and Ullman, depicting urban areas as having multiple centers of activity, reflecting the complexity of modern urban growth.

Social Stratification: Issues like gentrification, permanent underclass, and urban decay due to poor urban planning and the unavailability of affordable housing.
Economic Disparity: Inner-city residents often face higher unemployment, substandard housing, and are disproportionately affected during economic recessions.

Predicted growth in megacities in developing regions is coupled with challenges such as dualism and rapid urbanization without adequate infrastructure.
Urban models will help articulate urban dynamics and the impact of sustainable practices to tackle future urban challenges.

Smart Growth: Strategies focused on compact urban growth; cities like Portland exemplify this through urban growth boundaries and infill strategies.
New Urbanism: Advocates for walkable, mixed-use communities to enhance quality of life and reduce dependence on automobiles.
The role of public transportation is emphasized in reducing congestion in urban areas, crucial for sustainability and environmental consideration.