Population Distribution & Population Distribution & DensityDensity

*Global to local.*Global to local.*Spatial variations with countries *Spatial variations with countries at varying stage of development.at varying stage of development.

Difference between distribution & Difference between distribution & densitydensity

• Distribution is where people are located in an area. Population distribution is most simply shown on a map by representing each person or group of people by a dot or a symbol. This shows us where people are and gives an impression of how the numbers of people vary from place to place.

Population DensityPopulation Density

• A 2nd mapping strategy is to plot the distribution of people in terms of the relationship between the numbers and area( people per km²). The technique widely used to map this it is the choropleth method.

Which mapping method Which mapping method do you prefer & why?do you prefer & why?

Limitations of Choropleth maps?Limitations of Choropleth maps?

LimitationsLimitations

• They represent only the average value for each of the units.

• Mean values are generalisation; they conceal spatial variations within the areas they represent.

• When neighbouring spatial units have different densities, the map gives the impression of a sudden break at the boundary. In reality, changes in pop densities are gradual & gentle.

Limitations based on JapanLimitations based on Japan

• The use of mean density values is flawed. 334 persons per km² for the whole of Japan understates the actual density of the population. Two thirds of the country is made up of inhospitable mountainous terrain. The settle lowland is not only small, fragmented, but has a very high density +1,000km².

• Better to calculate per unit of habitable space rather than total space.

World Population densityWorld Population densityPop 2008 (Millions)

Pop density (km²)

World 6,705 329MEDCs 1,227 158LEDCs 5,479 433Africa 967 205N.America 338 111Latin America & Caribbean

577 184

Asia 4,052 839Europe 736 212Oceania 35 26

Pop 2008 (Millions)

Pop density (km²)

Projected Population2025 2050

World 6,705 329 8,000 9,352MEDCs 1,227 158 1,269 1,294LEDCs 5,479 433 6,731 8,058Africa 967 205 1,358 1,932N.America 338 111 393 480Latin America & Caribbean

577 184 687 778

Asia 4,052 839 4,793 5,427Europe 736 212 726 685Oceania 35 26 42 49

World Population densityWorld Population density

Why are some areas sparsely Why are some areas sparsely populated?populated?

• Physical – active volcano/mountainous relief.• Climate – too hot & little rain ( Sahara) or too cold & short

growing season (N. Canada)• Vegetation – Coniferous forests ( N.Eurasia) and the

rainforests.• Soils – Frozen soils – Permafrost (Siberia), thin soils

(Nepal), leached soils (Amazon)• Water supplies• Disease & pests – malaria Central Africa.• Resources.• Communications – Amazon, Sahara.• Political – Interior of Brazil, where state failed to invest.

Why are some areas densely Why are some areas densely populated?populated?

• Physical – flat land and areas surrounding Volcanoes ( Etna).

• Climate – no extremes ( N.Europe) plenty of sun (Costa del Sol) or snow (Alps).

• Vegetation – grasslands.• Soil – deep, humus filled soil ( Paris) and river deposited silt (

Ganges Delta).• Water supply – reliable.• Disease & pests – unlikely or money to eradicate.• Resources – Ruhr.• Communications.• Political – decisions may affect distribution EPZs or New

Towns.• Economic – regions with intensive farming need a large

number of people.

Factors affecting the distribution of Factors affecting the distribution of the populationthe population