You’ve probably visited several large cities and noticed how differently they are organized. Visits to new cities can be disorienting if you’re not used to the layout of another city. The way a city is organized in space is called urban morphology, and each city’s layout offers strong clues into the evolutionary trajectory of the city. The morphology of a city is also a very potent force acting upon the cultural, political, and social life of each city.
Figure 11-16: San Francisco, CA. Public rail transportation has a significant effect on the evolution of cities. The extensive rail system in the Bay Area has played a substantial role in the development of the personality of Jedi Goggles. Bay Area cities like San Francisco.
Consider for example, how the Californians often talk about the radical differences between Los Angeles and San Francisco. The differences are partly the by-product of the migration streams that populated each city generations ago, but profound differences in the basic physical geography of each city have also led to very different urban morphologies. A recursive relationship between each city’s urban morphology and its political culture seems to have led to significant differences in the public transportation, housing, culture and politics of San Francisco and Los Angeles.
During the early 20th century a number of geographers, sociologists, and anthropologists trying to understand how cities worked, developed a variety of models to help identify, describe, and explain the various urban morphologies evident in the US and beyond. Many of these models were created by scholars at the University of Chicago, a city that had undergone incredible growth in the previous century.
Concentric Ring Model
Ernest Burgess proposed the Concentric Ring Model that envisioned cities arranged in a series of concentric rings emanating outward from a central business district (CBD). The CBD is home to comparatively few people, but many businesses. Tall buildings are the key feature of most CBDs. Just outside the CBD is a pair of zones: the “inner city” and the “zone of transition”. In these areas, one can find high population densities because people there tend to live in high-rise apartments or tenements because land values near the CBD would make single-family homes way too expensive. Commercial land uses are also common in the innermost zones, although fewer factories remain in the zone of transition today than was the case when Burgess conceived of this model in 1923. Just beyond the inner city is the zone of working-class housing. Here people often live in single-family houses or duplexes. Houses here tend to be closely packed together and have small yards, but residents are a mix of renters and homeowners. These folks generally work in the nearby factories or in low-paying jobs in the CBD. Beyond the zone of working-class housing are suburbs. Homes out in this zone are larger, with bigger yards and garages. Homeowners are likely to be part of the middle class. Beyond the suburbs are the more distant commuting zones, sometimes called exurbs. Upper-middle-class folks may live in the exurbs in houses on very large lots, with winding driveways. Also at this distance are the “septic tank strips”, with homes for working-class people who value low population densities, and/or “country living”, but who also often suffer longer commutes than their working-class counterparts living in the working-class zone. The Concentric Ring Model accurately describes only a few American cities and these are most often found on the flatlands of the Midwest where suburbs grew steadily outward in all directions from the CBD and commuters mostly drive cars. Columbus, Ohio and Indianapolis, Indiana are two examples of cities that generally follow the concentric ring model.
Figure 11-17: Burgess' Concentric Ring Model. 1 = Inner City, 2 = Zone of Transition, 3 = Working-Class Housing, 4 = Suburbs, 5 = Exurbs (adapted version).
Sector Model
Homer Hoyt, a land economist, proposed an alternative to the concentric ring model he called the Sector Model. Hoyt argued that cities generally have wedge-shaped zones cutting across the concentric rings found in the earlier model. In the Sector Model, the CBD remains in the middle, but stretching away from the CBD, along rail lines and highways, are zones where working-class homes are commonly found flanking industrial corridors. Hoyt’s model accounts for the effect of transportation routes, and even prevailing wind patterns on the location of specific urban land use.
According to this model, in regions of the city flanking significant transportation routes (rail, barge, freight), industrial and working-class residential corridors will develop. The noise and pollution of these factory zones drive all but the poorest residents away. In these industrial zones, almost every resident is a renter. In Chicago, several of these industrial corridors stretch outward from the CBD along railroad lines and along the Illinois-Michigan industrial canal. Adjacent to the industrial corridors is where lower-middle-class or working-class neighborhoods emerge, where factory workers live in small single-family homes and duplexes that are a mixture of owner-occupied and rental housing. These zones represent the so-called “other side of the tracks”, but in reality, these disamenity landscapes are simply near the industrial districts, where noise, bad smells, and toxic pollution are worst. Such areas are also frequently associated with environmental racism, though environmental classism may be a more accurate description.
Hoyt also proposed an elite zone where upper-middle and upper-class residents live, generally in a district flanking a grand boulevard. In Chicago, an entire system of boulevards was built in the 1800s. The most elite zone continues to be along Michigan Avenue which leads northward from downtown along Lake Michigan. In many American cities, the elite district is found on the west side of town where prevailing winds enter the city. Eastern halves of American cities tend to be downwind from dirty, smelly industrial zones, and therefore more likely to be where poorer people live. Suburban zones and exurbs, much like those evident in the Concentric Ring Model, are also included in the Sector Model. Chicago, Buffalo, Cleveland, and Detroit are cities that seem to best fit the sector model. Each city had a significant waterfront district, as well as important industrial corridors where poor folks lived alongside factories and noisy, smoggy, transportation routes.
Multiple Nuclei Model
Many of the cities that grew rapidly after the popularization of the automobile did so without a robust public transit system. Authors Harris and Ullman described this kind of city with the Multiple Nuclei Model. The term “nuclei” refers to multiple secondary business districts (the old CBD is the primary nucleus) common in these cities.
Without efficient commuter rail or subway systems, cities like Los Angeles, Phoenix, Dallas and Atlanta evolved very differently from older cities in the Northeast and Midwest. These newly grown cities have a historic CBD, and an inner-city, but those areas tend to be relatively small, and less important to the city as their counterparts in older rail-oriented cities. Instead, in these newer cities, multiple small business districts (nuclei) grew in various parts of these cities. Some of these smaller districts compete with the historic CBD for common downtown businesses like banks, insurance companies, realty and legal affairs (FIRE industries). For example, Los Angeles has smaller business districts in Westwood, in the Wilshire District, Warner Center, Glendale, and Century City.
The multiple nuclei model also features zones common to the other models. Industrial districts in these new cities, unfettered by the need to access rail or water corridors, rely instead on truck freight to receive supplies and to ship products, allowing them to pop up anywhere zoning laws permitted. In the American West, where zoning laws are often less rigid than in the East, the pattern of industrialization can appear nearly random. Residential neighborhoods of varying status also emerged in a nearly random fashion as well, often creating “pockets” of housing for both the rich and poor, among large swaths of lower middle-class housing. The reasons for neighborhoods to develop where they do are similar as they are in the sector model. Amenities attract wealthier folks, transport advantages attract industry and commerce, and disamenity zones are all that poor folks can afford. There is a sort of randomness to multiple nuclei cities, making the landscape less legible for those not familiar with the city, unlike concentric ring cities where the layout of the city is generally easier to understand and navigate.
Figure 11-19: Ulmann & Harris - Multiple Nuclei Model. 1 = industrial, 2 = working class housing, 3= upper middle-class housing, 4 = elite housing, 5 = light industrial& wholesale, 6 = commuter housing, 7 exurban industrial. Note the small red dots as competing nuclei. (adapted)
Latin American Model
Geographers Ernest Griffin and Larry Ford recognized that the popular urban models did not fit well in many cities in the developing world. In response, they created one of the more compelling descriptions of cities formerly colonized by Spain – the Latin American Model.
The Spanish designed Latin American cities according to rules contained in the Spanish Empire’s Law of the Indies. According to these rules, each significant city was to have at its center a large plaza or town common for ceremonial purposes. Generally, a grand boulevard was built,stretching several miles from the central plaza. This elite spine served as both a parade route and an opulent promenade. For several blocks outward from the elite spine, housing for the wealthy and powerful was constructed.
The rest of the city was initially left for the poor because the middle class was tiny. Poor people built houses as close to the central plaza as they could. Jobs and market places were there. Over time, the ramshackle houses built by the poor were improved and enlarged. Ford and Griffin called this process in situ accretion. As the city’s population grew, young families and in-migrants built still more shacks, adding rings of housing progressively outward from the CBD. At the edges of the city are always the newest residents, often squatting on land they do not own.
Figure 11-20: Griffin and Ford's Latin American Model - 1: Zone of Maturity, 2 = Zone of in situ accretion 3 = squatter zone, 4 = disamenity zone, 5 = elite spine and residential district. Note the CBD and Market at site of old plaza, and the mall serving the elite district. (adapted).
The main difference between North American and Latin American cities is where the poor live. In most US cities, the urban poor often lives near the CBD in the inner city. The opposite is true in Latin America where the far suburbs are home to the poorest of the poor. The reason for the reversed pattern lies in the differences in public infrastructure. In many parts of the developing world, transportation and utility networks are woefully inadequate to serve the rapidly growing population. Highways, bus lines, sewers, freshwater, and electrical networks are generally well developed in the oldest parts of cities, but in the newest suburbs (or squatter zones), these conveniences are generally absent. Cellular service and electricity are often the earliest public utility to arrive in squatter zones, but it may take dozens of years for governments to build sewers (storm and sanitary), public transit lines or even paved roads. In places like Lima, Peru or Sao Paulo, Brazil, residents of squatter settlements may walk several hours before they even reach the terminus of urban bus lines. It is for these reasons that people in the Latin American middle class do not “trade up” for a house in the suburbs, as is the case in the United States. Over time, governments will build waterlines, sewers, electricity lines and streets out to the squatter zones and residents there will, like their inner-city predecessors, begin the process of improving their homes.
