# Population density

Population density is the measurement of the number of people living in a square area. Population density is also used with reference to plant and animal population as well in the understanding of ecology. However, it is a common measurement used on the human population.

It is found that favourable conditions like suitable land for agriculture, climatic conditions and economic development helps in increasing the density of population in a region. However, an area with an extremely high population density does not thrive and leads to higher risks of diseases, low employment, and higher mortality rates. With constant consumption of resources by a high number of people will only lead to a depletion of resources which will gradually lead to a low density.

The population density measurement is not absolute as there is a section of the population that is mobile and moves from one region to another. It gives an approximate number of people living in a region.

The National census is a good source of getting the population density data but it may again not be accurate as it is measured over gaps of 10 years.

## How is population density measured?

Population density is calculated by the below simple formula

Population density= Total number of people / the total square area of land (sq miles or kilometers)

There are various types of population density which is measured to understand human population. They are:

1. Arithmetic Density: This is the total number of people per square unit of land. It is also called as the real density. It does not take into consideration whether it is urban or rural or the terrain. It gives the measurement of people living in a square area.

2. Agricultural Density: Agricultural Density gives the number of farmers per unit of farmland or arable land.

3. Physiologic Density: The total number of people living per square unit of farmland or arable land gives the Physiologic density of population.

4. Urban Density: The urban density gives an understanding of the number of people living in an urban area. It is calculated by dividing the total number of people inhabiting the urban area by the total area of the urban land.

5. Residential Density: Residential density is a measurement of people living in the urban areas. It is calculated by dividing the number of people living in the urban area by the area of actual available residential land in the region.

6. Ecological Optimum: Ecological optimum is the number of people that can be supported by the available natural resources in an area.

## Factors affecting population density

There are a lot of factors that influence the population density in a region. Here a few major factors that impact the distribution and density of population:

1. Terrain: Agriculture is one of the main reasons that sustain a population. Hence, the terrain of the land is a deciding factor on the concentration and growth of a population in a region. Rich alluvial soil in the low lying areas offers ideal condition for the cultivation of crops while hilly, and rocky terrains makes it difficult to grow any crops. Therefore it is frequently found that the concentration of population is higher in the plain areas where agriculture is viable.
Terrains also impact the suitability for the construction of roads and railway tracks and runways. A difficulty in the construction of roads and other means of transport negatively impacts the growth of economic activities and delays development.

2. Climatic conditions: The climate of a region influences its habitability. Regions with extremes of climatic conditions are not suitable for settlement. If the climate is too hot or too cold or dry it will not support proper living conditions. Temperature and rainfall are very important factors that influence the suitability of a region for a population to thrive. A moderate climate favors agriculture which in turn favors the growth of a population. Although there are crops that do grow in extremes of temperatures or in high rainfall conditions they are not many and do not support the population in an economic way. It is often found that the population concentration or density follows the rainfall pattern in a region. Floods, heavy forestation and terrains do impact the possibility of agriculture and the settlement of a population even though rainfall maybe high in the area.

3. Soil: A good agricultural turnover requires good fertile soil. If the soil does not support agriculture, like desert soil or mountain soil then the population in the region will be low as well. Coastal plains and river banks tend to have highly enriched soil due to the annual deposit of alluvial soil in the region. This fertile soil supports rich growth of crops which in turn supports a high population density.

4. Water bodies: Water is one of the basic necessities of life hence it is only logical that human and animal population would thrive in regions where there is ample supply of fresh water. Rivers and lakes are the greatest source of fresh water which can be used for irrigation, drinking, cooking and for other household purposes. Rivers also provide a mode for transportation and a good supply of fishes. This is true in the coastal regions as well where population thrives on the harbor life and the fishing industry.

5. Natural resources: The human population has since ages taken advantage of the rich store of natural resources. This includes all resources above and below ground as well. Be it the living plant or animal resources or the non living soil and water as well. The availability of resources makes it suitable for inhabitation. Moreover when there is the availability of minerals in a location its mining and trading opportunities attracts people to settle there, resulting in an increase in the population density.

*Source- NASA Scientific Visualization Studio

6. Industries: Industrialization is a sure way to enhance all facets of a thriving society. Industrial growth offers higher employment opportunities which attract the capable workforce along with their families to these regions. This leads to the settlement of families leading to an increase in the population density. The existence of steady employment encourages the setting up of schools, hospitals and other supporting businesses which further attract people looking for opportunities.

7. Transportation and connectivity: Transportation is a major factor that influences the mobility and life pattern of a population in a region. The growth of population is directly related with the development of better roads and transport facilities. A good transport system provides better connectivity which ensures the possibility of securing employment, education, health care and commodities that are essential for an easy survival. So with a good transport system a region which does not have any natural resources or mode of employment or education may thrive.

8. Urbanization: Population density and urbanization are closely related by the fact that urban settings provide higher employment possibilities which encourage migration from other regions. The populations in the urban areas grow not just by the way of reproduction but a major chunk of the population that is added is due to the migration. Although the city limits do expand with time the population density does not see much variation other than in the upward direction.

## Application of population density data

Below are few of the applications of population density data that are being used widely:

• Population density data is one of the most critical parameters to assess the magnitude of a population that is exposed to risk. Prevention of risk and its management for natural hazards like wildfires, floods, earthquakes, droughts etc needs detailed and accurate information of the spatial distribution of the population in the region.

• Population density of an area is one of the most important factors that influence the effectiveness of a business and its marketing strategies. Understanding the number of people located within a radius and not just the consumers helps to identify the apt location for a business which will allow maximum accessibility. Population density data along with crucial market research information and detailed demographic trends can help to assess the sustainability and success of a business.

• Understanding the population density also helps the government in planning infrastructure that will help to provide the highly populated areas with health care facilities, schools, supply water, and other resources that can cater to the requirements of the population in the area. Population density data is of great importance in building roads and providing transport facilities.

• A Nation’s economic growth and understanding of production and consumption of resources is vital for its sustenance. Population density data offers a fair estimate of the production and consumption of resources along with the availability of employment and labor.

• Population density data is not limited to the measurement of human population only. Collecting population data of specific animal species or plant species in a particular area gives a fair idea of the ecology and also helps in understanding the biotic potential.

With the help of data received of the population density, many predictive models and assessment can be made for the future generations and the process and analysis as how to overcome the redundant and common problems of the society.