Inside a city, land uses form patterns: offices downtown, factories by rail lines, rich and poor neighborhoods in different places. Three classic models describe North American cities of the early and middle 1900s. They follow from central place thinking and from bid-rent: land near the center costs the most, so uses that can pay the most locate there.
Key idea
The concentric zone model (Ernest Burgess, 1925) shows rings around the central business district (CBD). The sector model (Homer Hoyt, 1939) shows wedges along transportation lines. The multiple nuclei model (Chauncy Harris and Edward Ullman, 1945) shows several centers, such as an airport, a university or a suburban business district.
Why it works
Each model captures something real. Burgess saw new immigrants arriving in the older, crowded zone next to downtown and families moving outward as they could afford it. Hoyt saw that a high-income area, once started along a scenic avenue, keeps growing outward in the same direction, while industry follows the rail lines. Harris and Ullman saw that cars and trucks let cities grow several centers. Later geographers added edge cities (Joel Garreau, 1991): big office and shopping centers at highway interchanges far from downtown.
Worked example: Which model?
A city's wealthy neighborhoods form a long wedge from downtown along a lakeshore drive, and factories line the railroad on the other side. Which model fits best?
- Rings would put each group all the way around the center.
- Here each group stretches outward in one direction, along a route.
Answer: The sector model.
Worked example: Many centers
A metropolitan area has its old downtown, a separate office cluster by the airport, and a university district with shops and housing around it. Which model fits best?
- There is more than one center, each with related uses around it.
Answer: The multiple nuclei model.
Common mistake
Thinking a model describes one real city exactly. Models are simplified patterns; each fits some cities and parts of cities better than others. A real city can show rings near the center, wedges along its rail lines, and several nuclei at its edge.