Three Models of Urban Land Use
The study of urban land use generally draws from three different descriptive models. These models were developed to generalize about the patterns of urban land use found in early industrial cities of the U.S. Because the shape and form of American cities changed over time, new models of urban land were developed to describe an urban landscape that was becoming increasingly complex and differentiated. Further, because these are general models devised to understand the overall patterns of land use, none of them can accurately describe patterns of urban land use in all cities. In fact, all of these models have been criticized for being more applicable to cities in the U.S. than to cities of other nations. Other criticisms have focused on the fact that the models are static; they describe patterns of urban land use in a generic city, but do not describe the process by which land use changes. Despite these criticisms, these models continue to be useful generalizations of the way in which land is devoted to different uses within the city. Below, we will examine the Concentric Zone Model, Sector Model and
Multiple Nuclei Model of urban land use.
Concentric Zone Model: The concentric zone model was among the early descriptions of urban form. Originated by Earnest Burgess in the 1920s, the concentric zone model depicts the use of urban land as a set of concentric rings with each ring devoted to a different land use (see
Figure 1). The model was based on Burgess’s observations of Chicago during the early years of the 20th century. Major routes of transportation emanated from the city’s core, making the CBD the most accessible location in the city. Burgess identified five rings of land use that would form around the CBD. These rings were originally defined as the (1) central business district,
(2) zone of transition, (3) zone of independent workers’ homes, (4) zone of better residences and (5) zone of commuters. An important feature of this model is the positive correlation of socio-economic statuts of households with distance from the CBD -- more affluent households were observed to live at greater distances from the central city. Burgess described the changing spatial patterns of residential areas as a process of "invasion" and "succession" . As the city grew and developed over time, the CBD would exert pressure on the zone immediately surrounding it
(the zone of transition). Outward expansion of the CBD would invade nearby residential neighborhoods causing them to expand outward. The process was thought to continue with each successive neighborhood moving further from the CBD. He suggested that inner-city housing was largely occupied by immigrants and households with low socio-economic status. As the city grew and the CBD expanded outward, lower status residents moved to adjacent neighborhoods, and more affluent residents moved further from the CBD.
Sector Model: Soon after Burgess generalized about the concentric zone form of the city,
Homer Hoyt re-cast the concentric ring model. While recognizing the value of the concentric ring model, Hoyt also observed some consistent patterns in many American cities. He observed, for example, that it was common for low-income households to be found in close proximity to railroad lines, and commercial establishments to be found along business thoroughfares. In
1939, Hoyt modified the concentric zone model to account for major transportation routes.
Recall that most major cities evolved around the nexus of several important transport facilities such as railroads, sea ports, and trolly lines that eminated from the city's center. Recognizing

that these routes (and later metropolitan expressways and interstate highways) represented lines of greater access, Hoyt theorized that cities would tend to grow in wedge-shaped patterns, or sectors, eminating from the CBD and centered on major transportation routes. Higher levels of access translate to higher land values. Thus, many commercial functions would remain in the
CBD, but manufcaturing activity would develop in a wedge surrounding transport routes.
Residential land use patterns also would grow in wedge-shaped patterns with a sector of lowerincome households bordering the manufacturing/ warehousing sector (traffic, noise and pollution making these less desirable locations to live) and sectors of middle- and higherincome households located away from industrtial sites. In many respects, Hoyt's sector model is simply a concentric zone model modified to account for the impact of transportation systems on accessibility.
Multiple Nuclei Model: By 1945, it was clear to Chauncy Harris and Edward Ullman that many cities did not fit the traditional concentric zone or sector model. Cities of greater size were developing substantial suburban areas and some suburbs, having reached significant size, were functioning like smaller busniess districts. These smaller business districts acted as satellite nodes, or nuclei, of activity around which land use patterns formed. While Harris and Ullman still saw the CBD as the major center of commerce, they suggested that specialized cells of activity would develop according to specific requirements of certain activities, different rentpaying abilities, and the tendency for some kinds of economic activity to cluster together. At the center of their model is the CBD, with light manufacturing and wholesaling located along transport routes. Heavy industry was thought to locate near the outer edge of city, perhaps surrounded by lower-income households, and suburbs of commuters and smaller service centers would occupy the urban periphery.
Burgess
In 1925, E.W. Burgess presented an urban land use model, which divided cities in a set of concentric circles expanding from the downtown to the suburbs. This representation was built from
Burgess's observations of a number of American cities, notably Chicago.
According to this model, a large city is divided in concentric zones with a tendency of each inner zone to expand in the other zone. Urban growth is thus a process of expansion and reconversion of land uses . For instance on this figure zone II (Factory zone) is expanding towards zone IV (Working class zone), creating a transition zone with reconversion of land use.
Although the Burgess model is simple and elegant, it has drawn numerous criticisms:

* The model is too simple and limited in historical and cultural applications up to the 1950s. It is a product of its time.
* The model was developed when American cities were growing very fast in demographic terms and when individual transportation was still uncommon. Expansion thus involved reconversion of land uses. This concept cannot be applied in a contemporary (second half to the 20th century) context where highways have enabled urban development to escape the reconversion process and settle in the suburbs.
* The model was developed for American cities and has limited applicability elsewhere. It has been demonstrated that pre-industrial cities, notably in Europe, did not at all followed the concentric circle model. For instance, in most pre-industrial cities, the center was much more important than the periphery, notably in terms of social status.
* There were a lot of spatial differences in terms of ethnic, social and occupational status, while there were low occurrence of the functional differences in land use patterns. The concentric model assumed a spatial separation of place of work and place of residence, which was not the generalized until the twentieth century.
However, the Burgess model remains useful for approximation of concentric urban development and as a way to introduce the complexity of urban land use.
http://www.geog.umontreal.ca/geotrans/eng/ch6en/conc6en/burgess.html
Homer Hoyt: Sector Model Harris and Ulman: Separate Nuclei Model
Source: adapted from H.
Carter (1995) Urban
Geography, Fourth
Edition, London: Arnold, p. 126.
Sector and Nuclei
Urban Land Use
Representations
A study done in
1939 by Homer Hoyt concluded that the land use pattern was not a random distribution, nor sharply defined rectangular areas or concentric circles but rather sectors . Communication axes are mainly responsible for the creation of sectors, thus transport has directional effect on land uses . We can see on the sector representation that Burgess transitional process is still part of land use changes, but there exist axes along which urban activities are oriented.
Following Hoyt’s development of a sectorial city, C.D. Harris and E.L. Ullman (1945) introduced a more effective generalization of urban land uses. It was brought forward that many towns and nearly all large cities do not grow from around one CBD, but are formed by the progressive integration of a number of separate nuclei in the urban pattern. These nodes become specialised and differentiated in the growth process and are not located in relation to any distance attribute, but are bound by a number of attributes:

* Differential accessibility . Some activities require specialized facilities such as port and rail terminals.
For instance, the retailing sector demands maximum accessibility, which is often different from centrality offered in the CBD.
* Land use compatibility . Similar activities group together since proximity implies improved interactions.
Service activities such as banks, insurance companies, shops and institutions are strongly interacting with each other. This can be defined as centripetal forces between activities.
* Land use incompatibility . Some activities are repelling each-other such as high quality residential and heavy industrial. This may be defined as centrifugal forces.
* Location suitability . Some activities cannot afford the rent of the optimal site for their location. They are thus locating at cheaper places, which are not optimal, but suitable for these activities.
Harris and Ullman polynuclear model was the first to represent the fragmentation of urban areas, specialised functions as well as suburbanisation.
http://www.geog.umontreal.ca/geotrans/eng/ch6en/conc6en/sectornuclei.html
Central Place Theory
 A Central Place is a settlement which provides one or more services for the population living around it.
 Simple basic services (e.g. grocery stores) are said to be of low order while specialized services (e.g. universities) are said to be of high order.
 Having a high order service implies there are low order services around it, but not vice versa.
 Settlements which provide low order services are said to be low order settlements.
Settlements that provide high order services are said to be high order settlements.
 The sphere of influence is the area of under influence of the Central Place.
 The minimum population size required to profitably maintain a service is the threshold population.
 Factors affecting a fall in the threshold population are
1.
A decrease in population
2.
Change in tastes
3.
Introduction of substitutes
Conclusions That Can be Made About
Places
Central
1.
The larger the settlements, the fewer their number
2.
The larger a settlement, the farther away a similar size settlement is
3.
The Range increases as the population increases
4.
The larger the settlement, the higher the order of its services. Deviations to this rule are: o Tourist resorts that have a small population but large number of functions. o Dormitory towns that have a large population but a small number of functions.
 Christaller made a number of assumptions such as:
All areas have
 an isotropic (all flat) surface
 an evenly distributed population
 evenly distributed resources
 similiar purchasing power of all consumers
 The theory points out that to prevent spheres of influence overlapping or having gaps, the best shape was a hexagon.

 The breaking point is where the consumer is equidistant from two/more similar services i.e. where the consumer is equally far from two or more centers.
 The formula to calculate it is djk=dij/(1+Square Root of(Pi/Pj)) where djk is the distance from j to k, dij is the distance between two towns, Pi/Pj are the populations of j and i and i is the bigger town.
In a market economy, most of the urban land can be freely sold or purchased. Thus land economics are concerned about how the price of urban land is fixed and how this price will influence the nature, pattern and distribution of urban land uses. Three concepts are at the core of the land rent theory:

Rent
. A surplus (profit) resulting from some advantage such as capitalization and accessibility. The rent is the highest for retail because this activity is closely related to
 accessibility.
Rent gradient
. A representation of the decline in rent with distance from a center. This
for each activity, which is how distance gradient is related to the marginal cost of distance influences its bidding rent. The friction of space
has an important impact on the rent gradient because with no friction all locations would be perfect locations. Retailing is the activity having the highest marginal cost, while single family housing have the lowest marginal cost.

Bid rent curve function
. A set of combinations of land prices and distances among which the individual (or firm) is indifferent. It describes prices that the household (firm) would be willing to pay at varying locations in order to achieve a given level of satisfaction (utility/ profits). The activity having the highest bid rent at one point is theoretically the activity that will occupy this location.
The above figure illustrates the basic principles of the land rent theory. It assumes a center which represents a desirable location with a high level of accessibility. The closest area, within a radius of 1 km, has about 3.14 square kilometers of surface (S=πD 2 ). Under such circumstances, the rent is a function of the availability of land, which can be expressed in a simple fashion as
1/S. As we move away from the center the rent drops substantially since the amount of available land increases exponentially.
Urban Morphology
* This is the distribution of different functions in a city
The Bid-rent Theory
* The Bid Rent Theory suggests different functions will bid differently for land in various parts of the city.

* It suggests the more accessible the site of land, the higher is its value.
Bid Rent Theory Diagram
Factors Influencing Land Values
1. Proximity to a secondary shopping center.
2. Local Site Characteristics
3. Government Policy
4. Security
Functional Zones Within a City
*
*
*
*
The CBD is the central, most accessible, most expensive part of a city
The Inner City is the area immediately surrounding the CBD. It has adverse social and economic conditions
The Industrial Zone
The Residential Zones. These are divided in 3 groups:
1. Low Income: 1st generation immigrants and poorer groups.
2. Middle Income: 2nd generation immigrants, and wealthier groups.
3. High Class Residential: The wealthiest groups
The Models of Urban Structure
* There are three basic models of urban structure
The Burgess Concentric Model
*
*
Burgess developed his model in 1924 based on a study of Chicago city
He arranged the zones in concentric circles around the CBD as shown in the diagram.
* Land Values Decrease outward from the CBD.
Burgess Concentric Model Diagram
Hoyts Sector Model
*
*
*
Homer Hoyt proposed The model in 1939
It was based on a study of 142 American cities
It arranges the zones in sectors radiating from the CBD
Hoyt's Sector Model Diagram
Peter Mann's Model of a Typical British City
* Peter Mann took Hoyt's and Burgess's models and combined them in his model of a typical British City in 1965.
* He based his model on studies of Sheffield, Nottingham and Huddersfield.
The Multi-Nuclei Theory
*
*
*
*
*
*
This theory was proposed by Ullmann and Harris in 1945.
It suggests that a city may have more than one nuclei/center apart from the CBD from which zones develop as shown in the diagram.
Multi Nuclei Theory Diagram
The Urban Field
* The Urban field is the region economically and socially linked to a city.
It is also referred to as
Urban Regions:The commuter villages/communities dependent on large towns
Functional Regions:The regions to/from which a city exports and imports.
Hinterland:The area served by a seaport

From Matt Rosenberg ,
Identified by Joel Garreau in 1991
There were a hundred thousand shapes and substances of incompleteness, wildly mingled out of their places, upside down, burrowing in the earth, aspiring in the earth, moldering in the water, and unintelligible as in any dream. - Charles Dickens on London in 1848; Garreau calls this quote the "best one-sentence description of Edge City extant."
They're called suburban business districts, major diversified centers, suburban cores, minicities, suburban activity centers, cities of realms, galactic cities, urban subcenters, pepperoni-pizza cities, superburbia, technoburbs, nucleations, disurbs, service cities, perimeter cities, peripheral centers, urban villages, and suburban downtowns but the name that's now most commonly used for places that the foregoing terms describe is "edge cities."
The term "edge cities" was coined by Washington Post journalist and author Joel Garreau in his
1991 book Edge City: Life on the New Frontier .
Garreau equates the growing edge cities at major suburban freeway interchanges around America as the latest transformation of how we live and work. These new suburban cities have sprung up like dandelions across the fruited plain, they're home to glistening office towers, huge retail complexes, and are always located close to major highways.
The archetypal edge city is Tysons Corner, Virginia, outside Washington, D.C. It's located near the junctions of Interstate 495 (the D.C. beltway), Interstate 66, and Virginia 267 (the route from D.C. to
Dulles International Airport). Tysons Corner wasn't much more than a village a few decades ago but today it's home to the largest retail area on the east coast south of New York City (that includes Tysons
Corner Center, home to six anchor department stores and over 230 stores in all), over 3,400 hotel rooms, over 100,000 jobs, over 25 million square feet of office space. Yet Tysons Corner is a city without a local civic government; much of it lies in unincorporated Fairfax County.
Garreau established five rules for a place to be considered an edge city:
1. The area must have more than five million square feet of office space (about the space of a good-sized downtown)
2. The place must include over 600,000 square feet of retail space (the size of a large regional shopping mall)
3. The population must rise every morning and drop every afternoon (i.e., there are more jobs than homes)
4. The place is known as a single end destination (the place "has it all;" entertainment, shopping, recreation, etc.)
5. The area must not have been anything like a "city" 30 years ago (cow pastures would have been nice)
Garreau identified 123 places in a chapter of his book called "The List" as being true edge cities and 83 up-and-coming or planned edge cities around the country. "The List" included two dozen edge cities or those in progress in greater Los Angeles alone, 23 in metro Washington, D.C., and 21 in greater New York
City.
Garreau speaks to the history of the edge city:
Edge Cities represent the third wave of our lives pushing into new frontiers in this half century. First, we moved our homes out past the traditional idea of what constituted a city. This was the suburbanization of America, especially after World War II. Then we wearied of returning
downtown for the necessities of life, so we moved our marketplaces out to where we lived. This was the malling of America, especially in the 1960s and 1970s.
Today, we have moved our means of creating wealth, the essence of urbanism - our jobs - out to where most of us have lived and shopped for two generations. That has led to the rise of Edge City.
(p. 4)

Predict The Movement of People and Ideas Between Two Places by Matt T. Rosenberg
For decades, social scientists have been using a modified version of Isaac Newton's Law of
Gravitation to predict movement of people, information, and commodities between cities and even continents.
The gravity model, as social scientists refer to the modified law of gravitation, takes into account the population size of two places and their distance. Since larger places attract people, ideas, and commodities more than smaller places and places closer together have a greater attraction, the gravity model incorporates these two features.
The relative strength of a bond between two places is determined by multiplying the population of city A by the population of city B and then dividing the product by the distance between the two cities squared.
The Gravity Model
Thus, if we compare the bond between the New York and Los Angeles metropolitan areas, we first multiply their 1998 populations (20,124,377 and 15,781,273, respectively) to get
317,588,287,391,921 and then we divide that number by the distance (2462 miles) squared
(6,061,444). The result is 52,394,823. We can shorten our math by reducing the numbers to the millions place - 20.12 times 15.78 equals 317.5 and then divide by 6 with a result of 52.9.
Now, let's try two metropolitan areas a bit closer - El Paso (Texas) and Tucson (Arizona).
We multiply their populations (703,127 and 790,755) to get 556,001,190,885 and then we divide that number by the distance (263 miles) squared (69,169) and the result is 8,038,300.
Therefore, the bond between New York and Los Angeles is greater than that of El Paso and
Tucson!
How about El Paso and Los Angeles? They're 712 miles apart, 2.7 times farther than El
Paso and Tucson! Well, Los Angeles is so large that it provides a huge gravitational force for El
Paso. Their relative force is 21,888,491, a surprising 2.7 times greater than the gravitational force between El Paso and Tucson! (The repetition of 2.7 is simply a coincidence.)
While the gravity model was created to anticipate migration between cities (and we can expect that more people migrate between LA and NYC than between El Paso and Tucson), it can also be used to anticipate the traffic between two places, the number of telephone calls, the transportation of goods and mail, and other types of movement between places. The gravity model can also be used to compare the gravitational attraction between two continents, two countries, two states, two counties, or even two neighborhoods within the same city.
Some prefer to use the functional distance between cities instead of the actual distance.
The functional distance can be the driving distance or can even be flight time between cities.
The gravity model was expanded by William J. Reilly in 1931 into Reilly's law of retail gravitation to calculate the breaking point between two places where customers will be drawn to one or another of two competing commercial centers. Opponents of the gravity model explain that it can not be confirmed scientifically, that it's only based on observation. They also state that the gravity model is an unfair method of predicting movement because its biased toward historic ties and toward the largest population centers. Thus, it can be used to perpetuate the status quo.
By Matt Rosenberg , About.com Guide
A country's leading city is always disproportionately large and exceptionally expressive of national capacity and feeling. The primate city is commonly at least twice as large as the next largest city and more than twice as significant. - Mark Jefferson, 1939

Geographer Mark Jefferson developed the law of the primate city to explain the phenomenon of huge cities that capture such a large proportion of a country's population as well as its economic activity. These primate cities are often, but not always, the capital cities of a country. An excellent example of a primate city is Paris, which truly represents and serves as the focus of France.
They dominate the country in influence and are the national focal-point. Their sheer size and activity becomes a strong pull factor, bringing additional residents to the city and causing the primate city to become even larger and more disproportional to smaller cities in the country. However, not every country has a primate city, as you'll see from the list below.
Some scholars define a primate city as one that is larger than the combined populations of the second and third ranked cities in a country. This definition does not represent true primacy, however, as the size of the first ranked city is not disproportionate to the second.
The law can be applied to smaller regions as well. For example, California's primate city is Los Angeles, with a metropolitan area population of 16 million, which is more than double the San Francisco metropolitan area of 7 million. Even counties can be examined with regard to the Law of the Primate City.
Examples of Countries With Primate Cities
 Paris (9.6 million) is definitely the focus of France while Marseilles has a population of 1.3 million.
 Similarly, the United Kingdom has London as its primate city (7 million) while the second largest city, Birmingham, is home to a mere one million people.
 Mexico City, Mexico (8.6 million) outshines Guadalajara (1.6 million).
 A huge dichotomy exists between Bangkok (7.5 million) and Thailand's second city, Nanthaburi (481,000).
Examples of Countries that Lack Primate Cities
 India's most populous city is Mumbai (formerly Bombay) with 16 million; second is Kolkata (formerly Calcutta) with more than 13 million; and third is less than 13 million.
 China, Canada, Australia, and Brazil are additional examples of non-primate-city countries.
 Utilizing the metropolitan area population of urban areas in the United States, we find that the U.S. lacks a true primate city.
With the New York City metropolitan area population at approximately 21 million, second ranked Los Angeles at 16 million, and even third ranked Chicago at 9 million, America lacks a primate city.
Rank-Size Rule
In 1949, George Zipf devised his theory of rank-size rule to explain the size cities in a country. He explained that the second and subsequently smaller cities should represent a proportion of the largest city. For example, if the largest city in a country contained one million citizens, Zipf stated that the second city would contain one-half as many as the first, or 500,000. The third would contain onethird or 333,333, the fourth would be home to one-quarter or 250,000, and so on, with the rank of the city representing the denominator in the fraction.
While some countries' urban hierarchy somewhat fits into Zipf's scheme, later geographers argued that his model should be seen as a probability model and that deviations are to be expected.
By Matt Rosenberg , About.com Guide
The buildings, concrete, asphalt, and the human and industrial activity of urban areas have caused cities to maintain higher temperatures than their surrounding countryside. This increased heat is known as an urban heat island. The air in an urban heat island can be as much as 20°F (11°C) higher than rural areas surrounding the city.
The increased heat of our cities increases discomfort for everyone, requires an increase in the amount of energy used for cooling purposes, and increases pollution. Each city's urban heat island varies based on the city structure and thus the range of temperatures within the island vary as well. Parks and greenbelts reduce temperatures while the Central Business District (CBD), commercial areas, and even suburban housing tracts are areas of warmer temperatures. Every house, building, and road changes the microclimate around it, contributing to the urban heat islands of our cities.
Los Angeles has been very much affected by its urban heat island. The city has seen its average temperature rise approximately 1°F every decade since the beginning of its super-urban growth since the World War II era. Other cities have seen increases of 0.2°-0.8°F each decade.
Various environmental and governmental agencies are working to decrease the temperatures of urban heat islands. This can be accomplished in several ways; most prominent are switching dark surfaces to light reflective surfaces and by planting trees. Dark surfaces, such as black roofs on buildings, absorb much more heat than light surfaces, which reflect sunlight. Black surfaces can be up to 70°F (21°C) hotter than light surfaces and that excess heat is transferred to the building itself, creating an increased need for cooling. By switching to light colored roofs, buildings can use 40% less energy.
Planting trees not only helps to shade cities from incoming solar radiation, they also increase evapotranspiration, which decreases the air temperature. Trees can reduce energy costs by 10-20%. The concrete and asphalt of our cities increases runoff, which decreases the evaporation rate and thus also increases temperature.

Increased heat enhances photochemical reactions, which increases the particles in the air and thus contributes to the formation of smog and clouds. London receives approximately 270 fewer hours of sunlight than the surrounding countryside due to clouds and smog. Urban heat islands also increase precipitation in cities and areas downwind of cities.
Our stone-like cities only slowly loose heat at night, thus causing the greatest temperature differences between city and countryside to take place at night.
Some suggest that urban heat islands are the true culprit for global warming. Most of our temperature gauges have been located near cities so the cities which grew up around the thermometers have recorded an increase in average temperatures worldwide.
However, such data is corrected by atmospheric scientists studying global warming.