Arithmetic Population Density

Arithmetic Population Density Definition

Arithmetic Population Density (APD) is a basic, important, and easy-to-understand demographic statistic.

Arithmetic Population Density Formula

To calculate arithmetic population density, find the total land area. This is usually expressed in square miles or square kilometers (there are 2.59 square kilometers in a square mile).

Second, find the total population for that land area.

Then, divide the population by the land area. It's as simple as that!

Some things to keep in mind:

• Population figures can vary based on whether they are from estimates or censuses, and what year they are considered accurate for.

• Some areas contain many temporary residents (such as college students or migrant laborers) that may or may not be included in APD calculations.

• APD should be based on land area only but may also be based on total area, which includes water surfaces enclosed by land areas.

Fig. 1 - Arithmetic population density of the world. Darker shades indicate higher densities, typically places that are highly urbanized. The lightest shade, found in deserts, sub-Arctic, and Arctic regions, cannot be farmed and/or have little or no freshwater.

Arithmetic Density vs Physiological Density

Arithmetic population density does not take into account factors like where people live across a space. This is important because people often cluster in cities and agricultural areas while having much lower densities in grazing areas and non-productive regions.

Physiological density is therefore a better measure for areas with cropland, because it is the ratio of people to cropland rather than people to total area. Knowing a country's physiological population density can tell you how many people need to be fed by each unit of area in crops.

Importance of Arithmetic Population Density

Why do we need to know arithmetic population density? Because it gives us the ability to make comparisons between countries, cities, states, and other geographical regions.

Dot-Density Maps

To get by the skewed figures of APD that don't show where people are clustered and where they are more dispersed, thematic maps like dot-density maps (or dot distribution maps) are useful. They give a much better picture of arithmetic population density than regional averages do.

Fig. 2 - Dot-density map shows the arithmetic population density of Illinois

Rural Areas

Arithmetic population density in relationship to infrastructure is a critically important factor in rural areas as well, but for the opposite reason to cities. Rural areas, which are often important for their agricultural production, tourism services, mining, and other economic activities, tend to have low APDs, particularly in developed nations like the US.

Low APDs are largely a result of mechanization in primary sector activities: far fewer people are needed to do what were once labor-intensive tasks like farming. This means that fewer jobs are available, so people need to move to places that can provide them with jobs.

Nevertheless, because the people who remain are critically important to the economic activities that take place, they must be provided the same services that people in urban areas receive: public schools, healthcare, grocery stores, paved roads, electricity, wireless Internet, and so forth. The problem is that many services rely on the tax base, and with fewer people, less tax money is available. Fewer consumers are available as well, making it cost-ineffective for companies to provide sufficient grocery stores and shops selling other necessary goods.

With fewer goods and services available and fewer jobs, rural areas also have a hard time competing with urban areas when it comes to job creation. People are unwilling to move to "remote" areas without the level of goods and services they are accustomed to closer to cities. Wages and salaries tend to be lower as well.

Arithmetic Population Density Example

The above discussion puts into perspective the idea that crowded places are "overpopulated" and need fewer people. This is completely contextual. The US is not the only country with large areas that suffer from underpopulation. Rural areas across the world are neglected because there are fewer consumers, and it is more expensive to provide for them.

Depending on the type of government, rural people may even be neglected because they have relatively few votes compared to urban areas.

Top Ten Most Dense Populations

The countries with the highest population densities (per square mile) are:

1. Monaco (47,508)

2. Singapore (19,727)

3. Bahrain (4,828)

4. Maldives (4,502)

5. Malta (4,317)

6. Bangladesh (2,955)

7. Vatican City (2,701)

8. Palestine (2,209)

9. Barbados (1,694)

10. Lebanon ( 1,386)

Fig. 3 - Monaco (foreground; background is France) is a city-state with the highest population density of any country. Manhattan, by virtue of its much taller buildings, is far more crowded, for example.

By way of comparison, Manhattan, one of the most affluent places on Earth, has a population density of 72,918 people per square mile. There simply is not a relationship between how crowded a place is and how affluent it is, though the top three above are all affluent (Monaco and Singapore are city-states). Places with high population densities may attract more jobs and thus more people, have higher tax bases, and thus more money to spend.

Top Ten Lowest APDs

Now let's turn to the other end of the spectrum. Here are the sovereign countries with the lowest population densities (per square mile) and the biomes that permit little or no habitation due to lack of water and/or extreme weather conditions that allow little or no agriculture:

1. Australia (9). Deserts

2. Canada (11). Arctic, sub-Arctic

3. Kazakhstan (18). Deserts

4. Russia (22). Arctic, sub-Arctic (tundra and taiga)

5. Bolivia (28). High-altitude deserts (Altiplano)

6. Chad (35). Sahara

7. Saudi Arabia (42). Arabian Desert

8. Argentina (42). Sub-Arctic (Patagonia)

9. Mali (46). Sahara

10. Niger (52). Sahara

Again, we can't derive a rule from the above list that relates underpopulation to affluence, because it includes some of the least developed (Chad, Mali, Niger) AND most developed or wealthy (Saudi Arabia, Canada, Australia) countries in the world.

What we DO know is that they all have problems providing goods and services to their rural populations. Remember that the APD divides total people by land area, and in some of these countries, 90% or more of the population lives in cities. Those who do not may live in tiny communities hundreds of miles apart from each other.

In much of the Canadian Arctic, Sahara, Siberia, and Australian bush, weather conditions make roads difficult or impossible. People may lose access to the outside world for months at a time, and during most or all of the year they as well as the goods they need have to come in and go out by plane. This raises the prices of consumer goods considerably.

Should places with extremely low APDs have people at all if it is so difficult and expensive to provide for them? Who are these people, in the first place?

As mentioned above, many are associated with critically important primary economic sector activities, which include grazing, mining, fishing, and timber extraction. On top of that, they may be Indigenous people, as is almost entirely the case in the Canadian Arctic and Sahara, for example. Their very cultural identity and way of life are tied to the land, but they also deserve to receive all the benefits of the modern world that people in cities enjoy.