Population density, or also called relative population, is an indicator that measures the number of people living in a territorial area.
The population density is studied, for comparison purposes, with which it is possible to know how populated a certain region is in relation to another. Even comparing it with the same region or country, but in different periods of time, which in turn makes it possible to differentiate the growth or decrease that the population has had over the years and thus be able to reveal the factors that have had an impact on it.
To obtain information and to calculate this indicator, it is necessary to make use of population censuses, registries, registers, historical demographic reports or cartographic tools.
Importance of knowing population density
By identifying how populated an area is, it is possible to discover important effects on the lives of its inhabitants. For example, if there is a very densely populated area, then the quality of life of its inhabitants could be reduced, if that causes a shortage of resources. It is in this sense that pressure is exerted on the available natural resources.
For the same reason, population density is part of the set of "Green Growth Indicators of the Organization for Economic Cooperation and Development (OECD)".
However, population density allows decisions to be made regarding public policies to meet the needs of the population. As is the communication routes, infrastructure, transportation, health, public health and education services.
Similarly, through statistical analysis, it is possible to estimate how the population density will behave in some years and this is how governments plan at the demographic level. All this, with the aim of estimating future needs and to establish the limits in the development of new houses and urbanization.
Population density formula
To measure the density of the population, the following formula is used:
DP = NP / S
DP = Population density.
NP = Number of people.
S = Area in Square Kilometers.
Population density example
If you want to know the population density of a certain city whose number of inhabitants is 45,000 and has an area of 10 km 2 . Then it is necessary to use the formula for population density and perform the following calculation:
NP = 45000
S = 10 km 2
DP = 45,000 / 10 = 4,500
These results are interpreted as having an average of 4,500 people per square kilometer.
High and low population density
High population density refers to the existence of a significant number of people living in a small area, which is measured in square kilometers.
For example, there are cases in the world in which more than 80% of the population lives in less than 50% of a country. Another example may be the fact that the population of 10 countries represents almost half of the world’s population.
On the contrary, when one speaks of a low population density, it refers to a small number of people, inhabiting every square kilometer.
Causes of a high or low population density
The distribution of the population is different throughout the planet, even on the same continent or in the same country, and this is due to various conditions. Which are mentioned below.
- Climate : Low temperatures make certain areas of the planet more inhospitable, such as those near the poles, which reduces the incentives to inhabit them. The same happens in regions with high temperatures such as deserts. On the contrary, in the case of temperate temperatures they are more hospitable for survival and have a better possibility of food production. They are generally below 500m above sea level, because the soils are more fertile than in the high mountains. In these cases also a greater possibility of survival and population growth.
- Migrations : The great historical displacements either due to the shortage of food, water or originated by wars have led to the existence of densely populated areas. At the same time, others were abandoned and, therefore, with a lower population density.
- Location of large industries: The location of industrial plants has caused a higher population density in certain cities in relation to others, this due to the Industrial Revolution.
- Urbanization: The need to provide more spaces for housing in some cities that, due to their geographical location, become business centers or companies, has changed the urban architecture of a smaller area per inhabitant. Which is reflected in an increase in the density of the population per square meter.
- Territory: The countries with the smallest territorial extension, naturally tend to be the most densely populated with respect to those with the largest territory.