AP HG U7

Urbanization

The process by which an increasing share of a population lives in cities. Ex: China's urbanization rate jumped from 20% in 1980 to over 60% today

Urban Agglomeration

A large urban area including a city and its surrounding suburbs. Ex: The Greater Tokyo Area is the world's largest agglomeration at 37+ million people

Megacity

A city with a population over 10 million. Ex: Tokyo, Delhi, São Paulo, New York

Primate City

A city that is disproportionately large and dominant compared to all others in the country. Ex: Bangkok, Thailand — over 10x larger than the second-largest Thai city

Rank-Size Rule

In a country, the second city is half the size of the largest, the third is one-third the size, etc. Ex: The US roughly follows the rank-size rule: New York, Los Angeles, Chicago

Central Place Theory (Christaller)

Cities exist in a hierarchical pattern to serve surrounding areas based on the range and threshold of goods. Ex: A small town offers groceries; a large city offers specialized medical care

Central Business District (CBD)

The commercial and business core of a city with the highest land values. Ex: Midtown Manhattan; The Loop in Chicago

Urban Hierarchy

The ranking of cities by size and function. Ex: World cities (New York, London) → national capitals → regional cities → towns → villages

World City / Global City

A city that serves as a hub in the global economy. Ex: New York, London, and Tokyo are the top three global cities

Edge City

A large node of business and retail outside the traditional city center. Ex: Tysons Corner, Virginia, outside Washington D.C.

Boomburb

Rapidly growing suburban cities with over 100,000 residents. Ex: Mesa, Arizona; Henderson, Nevada

Concentric Zone Model (Burgess)

A model showing cities organized in rings: CBD → factory/transition zone → working class → residential → commuter zone. Ex: Chicago in the early 20th century was used as the basis for this model

Sector Model (Hoyt)

Cities develop in sectors or wedges along transportation routes rather than rings. Ex: High-income residential areas in US cities often follow major roads outward

Multiple Nuclei Model (Harris & Ullman)

Cities develop around multiple centers rather than one CBD. Ex: Los Angeles developed around multiple centers: downtown, LAX area, Hollywood, etc.

Galactic/Peripheral Model (Harris)

A modern model showing cities surrounded by suburban nodes connected by highways. Ex: Atlanta with its perimeter highway (I-285) and surrounding edge cities

Latin American City Model (Griffin-Ford)

Cities in Latin America have a CBD with a commercial spine extending outward; wealthy residents live near the spine, poor in the periphery. Ex: Mexico City showing wealth concentrated near Paseo de la Reforma

Southeast Asian City Model

Cities in Southeast Asia lack a strong CBD; port zones and foreign commercial zones dominate; squatter settlements surround the city. Ex: Bangkok showing multiple commercial districts without a single dominant center

Sub-Saharan African City Model

Three CBDs (colonial, market, and transitional); surrounding ethnic neighborhoods and a mix of formal and informal housing. Ex: Nairobi showing a colonial CBD alongside informal settlements like Kibera

Gentrification

The renovation of deteriorated urban areas leading to rising property values and displacement of lower-income residents. Ex: Brooklyn, NY transformed from working-class to affluent over 20 years, displacing longtime residents

Urban Renewal

Government-led redevelopment of deteriorated urban areas. Ex: 1950s–60s US urban renewal projects demolished poor neighborhoods to build highways and housing projects

Suburbanization

The movement of people from cities to suburbs. Ex: Post-WWII American families moving to Levittown, New York

White Flight

The movement of white residents from cities to suburbs, partly in response to racial integration. Ex: Detroit's suburban growth in the 1950s–60s as Black families moved into previously white neighborhoods

Redlining

The discriminatory practice of denying services (loans, insurance) to residents of minority neighborhoods. Ex: The FHA in the 1930s–40s marked Black neighborhoods in red on maps, denying mortgages

Blockbusting

Real estate agents scaring white homeowners into selling cheaply by implying minorities would move in. Ex: Common in northeastern US cities in the 1950s–60s

Filtering

As wealthy residents move to newer housing, older housing becomes available to lower-income groups. Ex: Victorian homes in San Francisco's Mission District were once elite housing, later became low-income, now gentrifying

Squatter Settlement / Informal Settlement

Illegal, unplanned housing built by poor migrants on the edges of cities. Ex: Rio de Janeiro's favelas; Mumbai's Dharavi slum

Favela

A squatter settlement in Brazil. Ex: Rocinha, in Rio de Janeiro, is one of the largest favelas in South America

Counterurbanization

Movement of people away from cities into rural areas. Ex: Remote work enabling Americans to leave San Francisco for rural Idaho

Urban Sprawl

The uncontrolled outward expansion of cities into rural land. Ex: Phoenix, Arizona expanding aggressively into the desert

Smart Growth

Urban planning strategy aimed at creating compact, walkable, transit-friendly communities. Ex: Portland, Oregon's urban growth boundary limits sprawl

New Urbanism

Urban design movement emphasizing walkable, mixed-use communities. Ex: Celebration, Florida, designed as a walkable town with stores, schools, and homes clustered together

Greenbelts

Areas of protected land surrounding cities where development is restricted. Ex: London's greenbelt has protected farmland from being absorbed by suburban sprawl since the 1940s

Urban Heat Island

The phenomenon where cities are significantly warmer than surrounding rural areas due to asphalt, buildings, and waste heat. Ex: Phoenix temperatures can be 10°F+ hotter than surrounding desert at night

Zoning

Government regulation of how land in different areas can be used. Ex: Single-family residential, commercial, and industrial zones in US cities

Mixed Land Use

Combining residential, commercial, and industrial uses in the same area. Ex: New York City's SoHo neighborhood mixes apartments, galleries, and retail

Bid-Rent Theory

Land value decreases with distance from the CBD. Ex: A retail store pays $500/sq ft near Times Square but $5/sq ft in a rural area

Invasion and Succession

A new group moves into a neighborhood (invasion) and gradually replaces the existing group (succession). Ex: Latino communities gradually replacing white working-class residents in parts of Chicago

Transit-Oriented Development (TOD)

Concentrating high-density development around public transit hubs. Ex: Building apartments and shops around BART stations in the San Francisco Bay Area

Megalopolis

A chain of densely populated metropolitan areas merging together. Ex: BosWash — the nearly continuous urban corridor from Boston to Washington D.C.

Primate City Rule

When a country's largest city is more than twice the size of the second largest. Ex: Paris dominates France; no other French city comes close in size or influence

Disamenity Zone

The poorest, most dangerous areas of Latin American cities. Ex: Peripheral favelas and shantytowns surrounding São Paulo