Alright, it's time to talk about the 7 urban models which describe the internal structure of cities, Burgess, Hoyt Sector, and all the rest. And look, I probably don't have to tell you that understanding and remembering all of these is about as pleasant as having a gangrenous leg removed in the 18th century where your only option for anesthesia was a dirty stick to bite on. But stick with me and I'm going to try to splain it up real nice for you. So if you're ready to get them brain cows milked, let's get to it.
Okay, now before I start hurling urban models your way, let me give you a high level overview of why these are important. Like if we just start in with the models, then they're gonna be like a bunch of unfolded clothes on the floor in your closet and nobody wants that. So I'm gonna try to build a closet first and then get some hangers and organize all that information. Okay, first of all, these models tell us about the internal structure of cities themselves. Now in previous videos for this unit, we've talked about how and why cities are spatially arranged throughout the world and how they're related by interactions with one another.
What we have not talked about is why cities themselves are arranged in the way that they are in and of themselves. Like, why is that residential building over there and not over there? Why is that government building over there and not over there? And on and on. Now that's what these models seek to explain.
Second, you need to keep things real simple in your head and remember that every city is essentially only made up of three entities. A central business district, industrial or commercial district, and residential location. So each of the models are going to get progressively more complex, but they're all riffing on the same three. three-chord structure, so to speak. And finally, let me tell you what you need to know about each of these models for your exam.
You will never see a question asking you to reproduce one of these models, so that's a relief. But now let me tell you about the things you will need to understand about these models. First, you're going to need to know the strengths and limitations of each. Second, you need to know how innovations in transportation led to the new models.
Third, you're going to need to know why the different sectors are located where they are and the sectors' relationship to each other. And finally, you need to understand how . bid-rent theory helps explain the spatial arrangement of these models. And in case you thought you could forget bid-rent theory, let me just remind you that it says that land is most expensive in the central business district and then progressively decreases in cost the further you go from the central business district. Okay then, closet built, and I reckon we're ready to get cozy with each of these seven models.
Before we do, let me just mention that if you need help getting an A in your class and a 5 on your exam in May, you might want to check out my AP Human Geography Heimler Review Guide. It's got whole unit review videos that you won't find here on YouTube, note guides to follow along, practice questions, practice exams, and answer keys to all of it. So, you know, if that's something you're into, link in the description.
Okay, model number one, the Burgess Concentric Zone Model. And before I explain it, I should tell you that the first four models I'm going to show you are best for understanding the internal structure of cities mainly in North America. So Burgess was the first to take a crack at it in the 1920s, and he was studying Chicago in order to develop his model, so let's have a look. So Burgess argued that a city develops and grows outward in uniform concentric circles radiating out from its central business district.
So the first circle represents the CBD, and here you'll find the central transportation hub of the city, the headquarters of Major businesses and financial institutions, political offices, and all the rest. And then moving outward to Circle 2, also known as the Zone of Transition, we observe mixed land use with industrial centers and low-cost, high-density housing. And in 1920s Chicago, this is where the poorest urban residents lived. Then Circle 3 is where you find working class residential land use.
Now this is where many of the industrial workers lived, since they had jobs and could afford it and it gave them good access to the industrial sector in Circle 2, not to mention the services found in the CBD. And then in Circle 4 you have middle class residential land use. Now bid-rent theory says that the land is going to be cheaper here since it's further away from the CBD, so the middle class will have larger homes on bigger tracts of land. And then in Circle 5 we have upper-class residential homes.
This is the suburban commuter zone that features expensive single-family houses. And so the Burgess model answers the question of the internal structure of cities like this. The further from the CBD, the cheaper the land becomes, and thus the less dense the population becomes. And that is exactly what bid-rent theory would say. However, the main limitation of this model is that it's just too dang tidy to fit reality, just like every other model we've seen up to this point.
However, to be fair, when Burgess was observing Chicago in the 20s and 30s, the model was pretty accurate for describing that particular city. But once railways and automobiles became a more present reality for commuting, this model became quickly dated. All that to say, the main limitation of this model is that it only considers distance from the CBD as the main reason the internal structure of cities are arranged the way they are. that they are. So that increasing complexity led us to our next model, namely the Hoyt Sector Model.
Now this model sought to address the shortcomings of the Burgess Model by adding a second factor to explaining the internal structure of cities. Remember, Burgess only accounted for distance from the CBD, whereas the Hoyt Sector Model adds direction as a determining factor for the layout of urban areas. Or if you're sassy, you could say that the Hoyt Sector Model describes the internal arrangement of a city in terms of transportation and communication.
So basically this model predicts that cities will develop not in concentric circles like like Bird just said, but rather in wedge-shaped sectors like you see here. And why is that, says you? Well, says I, these wedges correspond to major transportation routes.
By 1939, when Hoyt introduced this model, the major transportation innovation that drove this urban structure was electric streetcars and elevated trains. both of which made it easier for people to commute to the CBD for work and for other services. So there at the center is the CBD, right where you'd expect it, and then each wedge extends outward along various transportation routes. In this model, lower income housing is still close to the industrial sector, while middle and upper classes can afford to move further away from the CBD and then commute to the city center. And the big difference between this and the Burgess model is that the various classes of residents build housing along the transpo- routes instead of locating them in the concentric circles of the Burgess model.
Okay, now the main limitation of this model, which is the limitation it shares with Burgess, is that it assumes that cities develop in a fairly predictable manner. The model predicts it. That's how it's going to be. But as it turns out, reality is a little messier than that, which leads us to our next model. Now, the multiple nuclei model was developed in the 1940s to address the shortcomings of the Hoyt Sector model, which is to say cities don't generally conform to a uniform shape.
Instead, Chauncey Harris and Edward Ullman, who developed this model, argued that a city develops around several distinct nodes, or nuclei, of different functional regions. Therefore, urban land use isn't predictable across all cities, but varies depending on the local context. And again, it was new innovations in transportation that led to the need for a new model, in this case the growing prevalence of automobiles.
Okay, so this model assumes that the CBD is not the central defining feature of land use, but rather that growth occurs independently around several different focal points or nuclei. In the previous two models, the CBD was the big old node that defined how the rest of the land was going to be used. But with highways being built and folks moving to the outskirts of urban areas, other less significant nodes were created that lessened their dependence on the CBD. And this is very much true in cities like Los Angeles, California or Houston, Texas. So the question I'm sure is burning in your brain right now is this, what determines the location and growth of those other nodes?
What an insightful question, and as it turns out, there are three factors that explain this. First, specialized activities require specialized land and infrastructure. For example, urban industrial sites spring up where there is well-developed transportation infrastructure to support their operations.
Second, there can be economic benefits for related companies locating in financial sectors or . business districts apart from the central business district. And then third, the negative consequences of industry and commercial practices, things like noise and pollution, can lead to the creation of new nodes away from the CBD and industrial sectors.
And mostly it's the affluent folks who can afford to move away from the CBD. Okay, so the main limitation of this model is that over time the defined borders of the nuclei began to blend together with their surroundings so that distinct nuclei were more difficult to identify. And wouldn't you know it, those limitations led to the development of a fourth model to describe the internal structure of North American cities, namely the Galactic City Model.
And as much as I wish I could tell you that this model was developed to describe how we're all going to end up living in Mos Eisley, commuting to the cantina in floating speeders, No. In reality, the Galactic Model was developed in response to rising urban sprawl and the normalization of cars for commuting. So here the influence of the CBD is decentralized and suburban edge cities develop which provide goods and services previously provided by the CBD. But all parts of the city are connected through highways and beltways.
People then use those beltways to travel between the distinct edge cities to take advantage of each settlement's unique offerings. And you can see this here in my fair city of Atlanta, Georgia. Here's Interstate 285 which acts as a a beltway connecting the various edge cities, which have become well-developed nodes of economic and residential land use, apart from the CBD in downtown Atlanta. And I happen to live in one of those edge cities, and if I can help it, I almost never travel to Atlanta because the roads down there are a hot...
But thanks to this kind of urban development, I don't really have any need to go to the city because everything I need is right here near my home. So in this model, there can be as many people employed in the suburbs as there are in the CBD, or in some cases, more. And although this model still applies to many North American cities today, a new limitation is becoming increasingly apparent. This model is gradually becoming more obsolete with the rise of the internet, which is giving people access to shop and work from a distance, therefore diminishing the importance of the beltways connecting the edge cities.
Okay, now just a reminder, those four models that we just ran through apply mainly to the development and structure of North American cities. But last time I checked, there are in fact other parts of the world, and as it turns out, these models don't do a great job of predicting the internal structure of those cities. So wouldn't you know it, three other models were developed to help explain those that I reckon we ought to talk about. Alright, first among these models is the Latin American model, which describes urban growth in Latin America, especially those areas that had previously been colonized by Spain.
And this model was specifically based on the structure of Mexico City. Now to understand this model, you need to remember that Latin American cities have developed on their own since becoming independent of former imperial powers, but that they still retain structural elements of colonial policy. So in this model, the location of the CBD and the market was established by Spanish law in the 16th century, and it retains that same spatial arrangement today. Now as you can see, the Latin American model is a combination of concentric circles and wedge-shaped zones.
The CBD is still central, but in this model it has two distinct areas. The CBD is where businesses and entertainment venues are located, but the market is where everyday goods are bought and sold. And the spine here represents high quality transportation infrastructure, and on either side of it is where you'll find upper class housing. Then notice that the CBD is surrounded by the zone of maturity, which is the Location of middle-class housing the next zone known as the zone of in situ accretion is the space for lower-income housing but is considered a transitional zone between the poorest residents and the zone of maturity and finally the poorest urban residents live here in the disamenity zones in the periphery and school quarter residences known as barrios. And these are the places where little to no amenities exist, things like police or running water.
Okay, now the next model to know is the Southeast Asian model, which is also highly influenced by colonial policies of the past. So here you can see that this wedge-shaped model is not organized. around a central business district, but rather water-based trading ports established by former imperial powers.
Also note that high-class residential isn't located at the edges like they are in the American models, but rather they're close to the port and the government zone. Additionally, you can see that the suburban areas intermingle with the squatter areas in a way that's pretty... different from the Latin American model.
And then one aspect unique to this particular model is the market gardening zone, which accommodates light agriculture. And one particularly good example of a city conforming to this model is Manila, which is the capital of the Philippines. And finally, let's consider the last model, the Sub-Saharan African model, which predicts the internal structure of cities and, you know, Sub-Saharan Africa.
So notice that this model has not one CBD, but three. A colonial CBD, the traditional marketplace, and a modernizing CBD. And then surrounding the CBD are many neighborhoods with distinct ethnic identities which are close to the mining and manufacturing zone where many of them work.
And then the outermost circle is largely made up of impoverished shanty towns and squatter settlements. And a city that conforms pretty nicely to this model is Lagos in Nigeria. Alright, that was a beefy one, so give yourself a high five for making it all the way through. You can click here to keep reviewing for Unit 6 videos, and you can click here to grab my AP Human- Human Geography Heimler Review Guide, which has everything you need to get an A in your class and a five on your exam in May. And hey, I'll catch you on the flip-flop.
Heimler out.