How to use the simulator
Three buttons along the top choose the model: Concentric Zone (Burgess), Sector (Hoyt) and Multiple Nuclei (Harris–Ullman). The page opens on Burgess.
For each model you see a schematic map with numbered zones, the model's name, author and date, a numbered key that matches the map, and a short description of how the model arranges the city.
- Concentric Zone (E. W. Burgess, 1925, Chicago): five rings. 1 Central business district (CBD), 2 Zone of transition (industry and deteriorating housing), 3 Working-class residential, 4 Better (middle-class) residential, 5 Commuter zone.
- Sector (Homer Hoyt, 1939): a CBD surrounded by wedges. 2 Transportation and industry, 3 Low-income residential, 4 Middle-income residential, 5 High-income residential corridor. On the map the industry wedge points east, low-income wedges sit on either side of it, and the high-income wedge points west, away from the industry.
- Multiple Nuclei (Harris and Ullman, 1945): nine separate zones linked by roads. Zones 1–5 repeat the CBD, wholesale and light manufacturing, and the three residential groups. The new zones are 6 Heavy manufacturing, 7 Outlying business district, 8 Residential suburb and 9 Industrial suburb.
The maps are schematic, not to scale. Flip between them to see the same land uses rearranged.
The key ideas
All three models describe the internal structure of mid-20th-century North American cities. They share one idea: land uses compete for location, and the one that can pay the most for a site usually gets it. That is the logic of bid-rent theory, where land is most expensive near the most accessible point.
- Concentric zone. The city grows outward from a single CBD. Status and housing age rise with distance, because better-off households can afford to commute. New groups move into inner zones and older residents move outward, a process Burgess called invasion and succession.
- Sector. Transport routes such as railways, rivers and main roads matter more than distance alone. Industry follows rail and water. Low-income housing grows next to industry, and high-income housing extends as its own corridor, often toward attractive land, away from noise and pollution.
- Multiple nuclei. Car ownership allows a city to grow around several centres, such as a port, a university, an airport or an outlying business district. Similar activities cluster together (offices near offices), and incompatible ones repel each other (high-income housing avoids heavy industry).
Each model fits some cities better than others. The AP course also covers the galactic city or peripheral model, with edge cities linked by a ring road, and regional models for Latin American, African and Southeast Asian cities. Those are not shown here.
Worked example
Scenario: A city grew up around a river port. Rail lines and factories run east from downtown along the river, and older, low-cost housing lines both sides of the rail corridor. West of downtown, a broad boulevard leads to large homes on higher ground that stretch for miles. Since the 1980s a technology campus near the airport, 25 km out, has drawn offices, hotels and new subdivisions.
Step 1: Look at the historic core. The land uses form wedges along transport lines: industry along the rail and river, low-income housing beside it, and wealthy housing extending in the opposite direction. That is the sector model. Select Hoyt in the simulator: the industry wedge (2) points east with low-income housing (3) on either side of it, and the high-income corridor (5) points west.
Step 2: Look at the newer growth. The airport campus is a separate centre with its own offices and housing, independent of downtown. That matches the multiple nuclei model, with zone 7 (outlying business district) and zone 8 (residential suburb).
Step 3: Rule out Burgess. Income does not rise evenly in every direction from the CBD. The wealthy area sits on one side only, so complete rings do not describe this city.
Step 4: Draw the conclusion. Here the older core follows Hoyt and the car-era edge follows Harris and Ullman; real cities often need more than one model.
Common mistakes on the AP exam
- Placing industry on the outskirts in Burgess. In the concentric zone model, industry is in zone 2, the zone of transition, right next to the CBD. Outer industry belongs to the multiple nuclei model (heavy manufacturing and the industrial suburb).
- Describing Hoyt's sectors as random. The wedges follow transport corridors. Say which route (rail, river, highway) shapes the sector.
- Mixing up the people and the dates. Burgess is concentric (1925), Hoyt is sector (1939), Harris and Ullman is multiple nuclei (1945).
- Applying the models worldwide without qualification. All three were built from U.S. cities. In many Latin American cities the wealthy live near the centre along a commercial spine, which is the reverse of Burgess.
- Giving a vague limitation. "It is old" is too weak. Name a specific gap, such as no role for cars, no edge cities, no physical geography or no effect of zoning laws.
When the AP exam uses this
These models are part of topic 6.5 (the internal structure of cities) in Unit 6, Cities and Urban Land-Use Patterns and Processes. Typical questions give a diagram or a description and ask which model it shows, ask you to compare two models, or ask you to explain why a model does not fit a city outside North America.