Larger and closer cities interact more — like gravitational attraction
Interaction between two places is proportional to the product of their populations divided by the distance squared. A big nearby city draws more migrants and trade than a larger distant one.
Three classic models of internal city organization
Burgess (concentric zones): CBD surrounded by rings. Hoyt (sectors): wedge-shaped zones along transport routes. Harris-Ullman (multiple nuclei): several business centers rather than one CBD.
Gentrification
Gentrification: reinvestment in low-income urban areas raises property values and displaces residents
Gentrification
Urban renewal process that benefits some while displacing others
Wealthier residents and businesses move into lower-income neighborhoods. Property values rise. Original lower-income residents are priced out (displaced). Revitalizes infrastructure but raises equity concerns.
Population Distribution
World population distribution: 90% live in Northern Hemisphere. Most in South/East Asia.
Population Distribution
Where people live — and why
Most densely populated: South Asia (India, Bangladesh), East Asia (China, Japan), Western Europe, Eastern US. Sparsely populated: deserts (Sahara, Australian Outback), rainforests (Amazon), polar regions, high mountains. Factors: climate, water availability, fertile soil, economic opportunity, historical settlement.
Urbanization Trends
Urbanization: cities grow as people move from rural to urban areas. Primate city = dominates country.
Urbanization Trends
The global shift from rural to urban living
More than 55% of world population now urban — projected to reach 68% by 2050. Primate city: disproportionately large city dominating a country's urban system (Bangkok, Paris, Mexico City). Urban primacy common in developing countries. Megacity: 10+ million population. Push from rural poverty + pull of urban opportunity.
Types of Regions
Ethnic vs cultural regions: formal (defined by one characteristic), functional (organized around a node), perceptual (mental image)
Types of Regions
Three ways geographers define regions
Formal (uniform) region: defined by one or more shared characteristics — the Corn Belt, the Bible Belt, Latin America. Functional (nodal) region: organized around a focal point or node — a city's commuter zone, a newspaper's circulation area. Perceptual (vernacular) region: exists in people's minds — 'the South,' 'the Middle East.'
Formal
Defined by shared characteristics
Functional
Organized around a central node
Perceptual
Exists in people's mental maps
Cultural Diffusion
Cultural diffusion: relocation (migrants carry culture), expansion (spreads outward), hierarchical (city to city first)
Cultural Diffusion
How cultural traits spread from place to place
Relocation diffusion: migrants physically carry culture to new locations. Expansion diffusion: spreads outward from source while staying there. Contagious: spreads through direct contact (disease model). Hierarchical: spreads from major cities to smaller ones, or elites to masses (fashion, music). Stimulus: idea sparks local innovation.
Malthusian Theory
Malthus: population grows geometrically, food supply arithmetically → inevitable famine
Malthusian Theory
Thomas Malthus's prediction about population and food supply
Malthus (1798): population doubles geometrically (1,2,4,8...) while food supply grows arithmetically (1,2,3,4...). Positive checks: famine, disease, war reduce population. Preventive checks: delayed marriage, celibacy. Neo-Malthusians: modern resource constraints. Critics: technology has expanded food supply — Green Revolution.
Suburbanization
Suburbanization: middle class leave cities for suburbs. White flight. Edge cities emerge.
Suburbanization
The post-WWII transformation of American urban geography
Post-WWII suburbanization: GI Bill mortgages, Interstate Highway System, cheap cars, white flight (racial segregation drove middle-class whites to suburbs). Consequences: urban decline, sprawl, car dependency. Edge cities (Garreau): suburban nodes with more jobs than bedrooms — Tysons Corner, Schaumburg. Now: 'new urbanism' pushes back.
Refugees and Forced Migration
Refugee vs immigrant: refugee = forced to flee persecution. Immigrant = voluntary movement.
Refugees and Forced Migration
The distinction between voluntary and involuntary migration
Refugee: person who has fled their country due to well-founded fear of persecution based on race, religion, nationality, political opinion, or social group (1951 UN Convention). Internally displaced person (IDP): forced from home but still in own country. Asylum seeker: requesting refugee status. Economic migrant: voluntary, seeking better opportunities.