The definition of population density is a way to measure the number of populations in a specific area. The method of calculating population density is by the number of people per square mile or square kilometer of a given area. Population density is a key geographical term that can be used to calculate the number of living organisms per unit area, but it is most commonly applied to humans.
The calculation of population density gives an average number, and there are several ways to measure it. The most common formula, however, is to divide the number of people by the area considered in square feet, miles, kilometers, or other measures of land. The fundamental reason for using population density is to determine the number of people that live, on average, per square unit measure (kilometer or mile). From the basic formula stated above (people/square unit of area), some calculations exclude bodies of water or other otherwise uninhabitable regions. Usually, population density is calculated for a city, county, state, country, other territories, or the whole world.
The so-called arithmetic density does not exclude any areas from the equation that are uninhabitable for humans. It just calculates the area of land considered and the people living in that area. It tells us the average number of people in an area without taking any other factors into account.
Arithmetic density = The total number of people / Area of land
For example, the population density of the United States is approximately 69 persons per square mile overall. High population density levels created crowding. The tendency of large numbers of people to live in an urban area creates congestion. However, if the United States had a population of about 300 million people, it would not suffer from crowding; in fact, much of its territory would remain empty. On the east coast of the United States, the area from Boston to Washington, DC, has been termed a megalopolis because of its high population density. High population density contributes to increased energy utilization for transportation and pollution. This can be seen in the most polluted countries as well.
While arithmetic density is the most common formula used to identify the number of people living in a specific area, other calculation methods have been developed. We’ll see how each works relating to the needs that created them.
Agricultural density = rural population / area of arable land
Physiological density = population / area of arable land
Residential density = people living in an urban area / area of residential land
Urban density = people living in an urban area / area of urban land
Ecological optimum = population density supported by natural resources.