Humanities › Geography Population Geography An Overview of Population Geography Share Flipboard Email Print Commuters pass through Grand Central Terminal during morning rush hour December 19, 2005 in New York City. Population geographers study the density and distribution of people on the earth. Mario Tama / Staff/ Getty Images News/ Getty Images Geography Population Basics Physical Geography Political Geography Country Information Key Figures & Milestones Maps Urban Geography By Amanda Briney Geography Expert M.A., Geography, California State University - East Bay B.A., English and Geography, California State University - Sacramento Amanda Briney is a professional geographer. She holds an M.A. in geography and a Certificate of Advanced Study in Geographic information Systems (GIS). our editorial process Amanda Briney Updated May 09, 2019 Population geography is a branch of human geography that is focused on the scientific study of people, their spatial distributions and density. To study these factors, population geographers examine the increase and decrease in population, peoples' movements over time, general settlement patterns and other subjects such as occupation and how people form the geographic character of a place. Population geography is closely related to demography (the study of population statistics and trends). Topics in Population Geography Closely related to population distribution is population density — another topic in population geography. Population density studies the average number of people in an area by dividing the number of people present by total area. Usually these numbers are given as persons per square kilometer or mile. There are several factors which affect population density and these are often subjects of population geographers' study as well. Such factors can relate to the physical environment like climate and topography or be related to the social, economic and political environments of an area. For example, areas with harsh climates like California's Death Valley region are sparsely populated. By contrast, Tokyo and Singapore are densely populated because of their mild climates and their economic, social and political development. Overall population growth and change is another area of importance for population geographers. This is because the world's population has grown dramatically over the last two centuries. To study this overall subject, population growth is looked at via natural increase. This studies an area's birth rates and death rates. The birth rate is the number of babies born per 1000 individuals in the population every year. The death rate is the number of deaths per 1000 people every year. The historic natural increase rate of population used to be near zero, meaning that births roughly equaled deaths. Today, however, an increase in life expectancy due to better healthcare and standards of living has lowered the overall death rate. In developed nations, the birth rate has declined, but it is still high in developing nations. As a result, the world's population has grown exponentially. In addition to natural increase, population change also considers net migration for an area. This is the difference between in-migration and out-migration. An area's overall growth rate or change in population is the sum of natural increase and net migration. An essential component to studying world growth rates and population change is the demographic transition model — a significant tool in population geography. This model looks at how population changes as a country develops in four stages. The first stage is when birth rates and death rates are high so there are little natural increase and a relatively small population. The second stage features high birth rates and low death rates so there is high growth in the population (this is normally where least developed countries fall). The third stage has a decreasing birth rate and a decreasing death rate, again resulting in slowed population growth. Finally, the fourth stage has low birth and death rates with low natural increase. Graphing Population Developed nations usually have an equal distribution of people throughout the different age groups, indicating slowed population growth. Some, however, show negative population growth when the number of children are equal or slightly lower than older adults. Japan's population pyramid, for example, shows slowed population growth. Technologies and Data Sources In addition to census data, population data is also available through government documents like birth and death certificates. Governments, universities and private organizations also work to conduct different surveys and studies to gather data about population specifics and behavior that could be related to topics in population geography. To learn more about population geography and the specific topics within it, visit this site's collection of population geography articles.