Urban Networks and Systems: Evolution and Challenges
Urban Networks
Early urban centers like Gerund (Gerona), Lerga, and Tarraco (modern Tarragona) predate Rome. Rome itself, a hub of urban civilization, spread its influence throughout its empire. Notable examples include the Alcántara Bridge, which stood for 2000 years, and the city of Ampurias. After the Roman decline, urban life diminished, with cities like Tarraco becoming depopulated and Empuries falling into ruin. Later, cities like Madrid, with Arabic origins, emerged.
Urban Systems
These dynamic systems thrive on exchanges between different centers. A key function is the metropolitan area, facilitated by transportation networks that connect people and places. A controlled city system exemplifies this.
Elements of Urban Systems
- Ground-Estate: The physical space.
- Infrastructure: Visible elements like the metro (e.g., Barcelona’s L9) and company headquarters.
- Mobile Elements: Trains, buses, etc.
- Communication and Transportation Networks: Internet, mobile networks.
- Legal System: Shared rules and regulations, such as transportation ordinances.
Relationships Between Elements
- Population movements
- Movement of goods and capital
- Movement of information (e.g., television, internet)
Flow Models
These models represent the exchanges (people, goods, information) between different urban centers.
Urban Regions
Urban regions exhibit specialization and interdependence between centers, increasing with development.
Urban Hierarchy
- Urban Areas: Defined by population size and administrative boundaries.
- Central City: The urban core with administrative boundaries.
- Metropolitan Area: A central city and surrounding smaller cities with interconnected flows.
- Conurbation: Cities growing together without a dominant center.
- Megalopolis: A large urban region with multiple cores, over 20 million people, and complex economic networks.
Types of Settlement
- Urban municipalities (over 10,000 inhabitants)
- Intermediate municipalities (2,000-10,000 inhabitants)
- Rural municipalities (under 2,000 inhabitants)
Urbanization
Urbanization involves the growth of cities in number, population, and area. Until the mid-19th century, most populations were rural. The Green Revolution and Industrial Revolution spurred urban growth, particularly in Europe and North America. In Asia and Africa, urbanization sometimes preceded industrialization, driven by factors like unequal land distribution and rural population growth.
Urbanization is characterized by:
- Rapid growth of cities
- Expansion of urban lifestyles
Types of Cities
- Pre-industrial cities: Primarily agricultural, with limited industry and services.
- Industrial cities: Driven by industrial growth, often with distinct industrial zones.
- Post-industrial cities: Characterized by a shift away from manufacturing towards service industries.
Different Rhythms of Urbanization
Urbanization rates vary globally. While European urban population growth stagnated between 1995 and 2000, Africa’s urban population grew significantly. Rapid, unplanned urbanization in areas like Lagos and Cairo leads to urban sprawl, characterized by inadequate infrastructure and services.
Urban Sprawl
Urban sprawl often results in the development of shantytowns and slums, lacking essential services. This unplanned growth is common in developing countries experiencing rapid urbanization, often driven by migration from rural areas due to factors like displacement by large land acquisitions.
Cities play a significant role in national economies, as seen in Osaka and Tokyo (36% of Japan’s GDP), Bangkok (37% of Thailand’s GDP), and Manila (25% of the Philippines’ GDP).