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AP Human Geo

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Unit 6

6.4 The Size and Distribution of Cities

6 min read•january 12, 2023

Riya Patel

Harrison Burnside

Riya Patel

Harrison Burnside

AP Human Geography 🚜

320 resources

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Introduction

The size and distribution of cities refers to the pattern of urbanization and the way that cities are arranged within a country or region. Factors that can influence the size and distribution of cities include geography, transportation networks, economic development, and cultural and political factors.

Cities can vary greatly in size, from small villages with a few hundred residents to large metropolises with millions of people. The distribution of cities within a country or region can also vary, with some regions having a few large cities and others having many smaller cities.

Understanding the size and distribution of cities can be important for a variety of purposes, such as planning for infrastructure and services, understanding patterns of economic development, and examining trends in population growth and urbanization.

Here is an example of the size and distribution of cities in a hypothetical country:

The largest city, "Metropolis," has a population of 10 million and is located in the center of the country. It is a major economic hub and serves as the cultural and political center of the country.
The second largest city, "City A," has a population of 5 million and is located on the coast. It is a major port and is a center of international trade.
The third largest city, "City B," has a population of 3 million and is located in the mountainous region in the north of the country. It is a center of tourism and outdoor recreation.
The fourth largest city, "City C," has a population of 2 million and is located in the agricultural region in the south of the country. It is a center of food processing and distribution.

The Rank Size Rule

The Rank Size Rule is a pattern observed in the distribution of populations among urban areas, which states that the population of a city is inversely proportional to its rank in the hierarchy of cities. In other words, the rule suggests that the largest city in a region will be about twice the size of the second largest city, three times the size of the third largest city, and so on.

For example, according to the Rank Size Rule, the population of the largest city (ranked 1) in a country is typically larger than the population of the second-largest city (ranked 2) by a factor of about 2. The population of the second-largest city is typically larger than the population of the third-largest city (ranked 3) by a similar factor, and so on.

The Rank Size Rule is often used to describe the distribution of urban populations and to predict the size of cities in a region. It is important to note that the Rank Size Rule is a general trend and may not hold true in all cases, as the size and importance of cities can be influenced by a variety of factors such as geography, infrastructure, and economic development.

How Does the Rank Size Rule Work?

Below is a representation of how the Rank Size rule can play out:

Largest City in a Country - Population of 1,000,000

1,000,000 / 1

2nd Largest City in a Country - Population of 500,000

1,000,000 / 2

3rd Largest City in a Country - Population of 333,333

1,000,000 / 3

4th Largest City in a Country - Population of 250,000

1,000,000 / 4

5th Largest City in a Country - Population of 200,000

1,000,000 / 5

Example

Here is an example of how the Rank-Size Rule might be applied to a region with six cities:

The largest city has a population of 200,000
The second largest city has a population of 100,000 (half the size of the largest city)
The third largest city has a population of 66,666 (two thirds the size of the second largest city)
The fourth largest city has a population of 50,000 (three fourths the size of the third largest city)
The fifth largest city has a population of 40,000 (four fifths the size of the fourth largest city)
The sixth largest city has a population of 33,333 (five sixths the size of the fifth largest city)

It is important to note that this is just an example and that the actual population sizes of cities in a region may not conform exactly to the Rank Size Rule. The Rank Size Rule describes a general trend and may not prove to be true in all circumstances.

Problems with the Rank Size Rule

There are several problems with the Rank Size Rule that limit its usefulness as a predictive tool:
1. The Rule is based on a log-linear relationship between city size and rank, which may not hold true in all cases.
2. The Rule does not take into account factors that can influence the size and importance of cities, such as geography, infrastructure, and economic development.
3. The Rule does not account for changes over time, and may not accurately reflect the current distribution of urban populations.
4. The Rule is based on data from a limited number of countries, and may not be applicable to all regions.

According to the rank size rule, the second-largest city in a country should be about half the size of the largest city, the third-largest city should be about one-third the size of the largest city, and so on. However, many countries do not follow this rule exactly, and some have large cities that are much larger than would be expected based on their rank. These cities are often referred to as primate cities.

Example

In the United States, for example, the top five cities (New York, Los Angeles, Chicago, Houston, and Phoenix) all have populations that are relatively close to what would be expected based on their rank. However, the sixth-largest city, Philadelphia, has a population that is significantly smaller than what would be expected based on its rank. This deviation from the rank-size rule is due to the fact that New York City is a particularly large and influential city, and it serves as a primate city for the country.

Primate City

A primate city is the largest city in a country or region, and is significantly larger and more influential than any other city in the region. Primate cities often serve as the economic, cultural, and political center of their region and may have a disproportionate influence on the rest of the country.

An example of a primate city is Mexico City, which is the largest city in Mexico and the capital of the country. It is also the most populous city in North America and one of the most populous cities in the world. Mexico City is the cultural, financial, and political center of Mexico, and it is home to many important institutions and landmarks, including the National Palace and the Metropolitan Cathedral. The city has a significant impact on the country's economy and culture, and it is the hub of much of Mexico's transportation, communication, and trade.

Primate cities can be found in many other countries around the world, and examples include:

Tokyo, Japan
New York City, United States
London, United Kingdom

Mumbai, India
Jakarta, Indonesia
São Paulo, Brazil
Cairo, Egypt
Moscow, Russia
Shanghai, China

It is important to note that the term "primate city" can also be used to describe the dominant city in a region that is not the national capital. For example, Chicago is sometimes referred to as the "primate city" of the Midwest United States, even though it is not the capital of the country.

Chart of Advantages and Disadvantages

The chart below describes the advantages and disadvantages of a Primate City!

Source: Mr Tredinnick’s AP HuG Class Website

Chart Summary

Here are some potential advantages of a primate city:

Economic dominance: A primate city can be a major economic hub and may attract a large number of businesses and industries, leading to job opportunities and economic growth.
Cultural influence: A primate city may be a center of culture and arts, and may have a disproportionate influence on the rest of the country in terms of artistic and cultural trends.
Political importance: A primate city may be the center of political power and decision-making in a country or region, and may have a strong influence on national and regional policies.
Transportation hub: A primate city may have a comprehensive network of roads, railways, and airports, making it a major transportation hub and facilitating the movement of people and goods.

Here are some potential disadvantages of a primate city:

Overcrowding: A primate city may experience overcrowding and a shortage of housing as a result of its large population.
Traffic congestion: A primate city may have heavy traffic and congestion due to the large number of people and vehicles present in the city.
Social and economic inequality: A primate city may have a high level of social and economic inequality, with a large gap between wealthy and poor residents.
Environmental issues: A primate city may face environmental issues such as air pollution and waste management due to its large population and economic activity.

Browse Study Guides By Unit

🗺Unit 1 – Thinking Geographically

👪Unit 2 – Population & Migration

🕌Unit 3 – Cultural Geography

🗳Unit 4 – Political Geography

👨‍🌾Unit 5 – Agriculture & Rural Land-Use