The numbers of people and the way they are concentrated in different areas (population density) is influenced by climatic conditions, physical relief and available resources.

There are more than six billion people in the world today. Three quarters of them are located in economically less developed countries.

The "empty areas" show where few people live and the landscape is not amenable to large scale human settlement. These are usually deserts, tundra, rainforests, ice caps or mountainous areas.