Population distribution describes how people are spread across an area. The pattern is highly uneven. Large concentrations are found in parts of eastern and southern Asia, Europe and northeastern North America. Deserts, polar regions, high mountains and some forest interiors, by contrast, are sparsely populated.

A distribution map shows where people live. Population density measures the number of people per unit area. However, a national average can conceal major contrasts within a country because it treats all areas as though they are occupied equally.

Physical factors

The physical conditions of a place create both opportunities and constraints.

• Climate: Moderate temperatures and reliable rainfall usually favour farming, water supply and settlement. Extreme cold, heat or aridity tend to restrict population.
• Relief and altitude: Building, cultivation and transport are easier on lowlands and gently sloping land. Steep slopes and high altitudes raise costs and may reduce oxygen availability.
• Water supply: River valleys, lakes and accessible groundwater provide water for domestic use, irrigation and industry, while also supporting transport.
• Soils and vegetation: Fertile soils allow productive agriculture and can support dense rural settlement. Farming may be limited by infertile, waterlogged or heavily leached soils.
• Natural resources: Minerals and energy resources draw workers and investment. As a result, settlements may develop in otherwise difficult environments.
• Natural hazards: Frequent flooding, drought, volcanic activity or earthquakes can discourage settlement. Even so, people may stay when the benefits outweigh the risks.

Physical factors alone don’t determine population distribution. Technology can ease these constraints through irrigation, air conditioning, flood control, imported food and improved construction.

Human factors

• Economic opportunity: Jobs, markets and services draw people towards cities, industrial regions and commercial farming areas.
• Transport and accessibility: Ports, navigable rivers, roads and railways improve links between settlements and other markets.
• Historical settlement: Farming regions, trade routes and administrative centres established long ago often retain large populations.
• Political conditions: Security and stable government may encourage settlement and investment. Conflict and persecution, on the other hand, can cause displacement.
• Government policy: States can influence settlement through new capitals, development corridors, land schemes or restrictions on movement.
• Social and cultural ties: Decisions to stay or move are shaped by family networks, language, religion and attachment to place.

The influence of each factor shifts over time. Discovering a resource may attract population quickly, while environmental decline, economic restructuring or conflict can reverse an earlier concentration.

Economic development means improvement in economic well-being and productive capacity. Countries are commonly classified by income, though development also includes wider changes in employment, infrastructure and access to opportunities.

Income classifications

Income per person, usually gross national income per capita, can be used to classify countries. The thresholds are updated periodically, so countries may move from one category to another.

Global pattern

High-income countries are strongly represented in North America, Europe and parts of East Asia and Oceania. Many low-income countries are concentrated in sub-Saharan Africa. Middle-income countries are found across Latin America, Asia, North Africa and parts of Europe. These patterns are broad; they aren’t fixed regional rules.

Development is uneven across space at every scale. High national income doesn’t make every region or household prosperous. In a middle-income country, rapidly growing cities may exist alongside poorer rural or peripheral regions.

Limits of classification

Income classifications provide a consistent measure for global comparison, but they simplify complex conditions:

• averages can hide internal inequality;
• living costs vary between places;
• unpaid and informal work may be under-recorded;
• income alone cannot show how evenly opportunities and services are distributed;
• development changes over time, particularly in emerging economies.

Economic classification is best used as a starting point for identifying global patterns, rather than as a complete description of a country.

National averages can conceal sharp differences within a country. People and economic activity often cluster in accessible urban regions, along transport corridors and near jobs. Remote areas or places with difficult environmental conditions tend to be much less densely populated.

Voluntary internal migration

Voluntary internal migration is movement chosen by a person or household within the borders of a country. It includes rural-to-urban, urban-to-urban, rural-to-rural and urban-to-rural movement.

People weigh pressures at their origin against attractions elsewhere. A lack of work, land or services may push them to leave. Employment, education, health care, family networks and perceived opportunity can draw them to another place. This movement is selective: younger adults and those with enough money, skills or contacts are often better able to migrate.

Internal migration shifts labour, demand and investment from one area to another. Destination cities may grow faster, while origin areas experience changes in their age structure and workforce. Migrants can keep ties with the places they left through return visits, information and remittances.

Core–periphery patterns

A core–periphery pattern is an unequal spatial arrangement in which a well-connected core concentrates population, investment, employment and decision-making, while a less accessible periphery has fewer opportunities and weaker connections.

Once growth begins, it may reinforce itself. Firms choose locations close to large markets and skilled labour, creating jobs that attract more migration and infrastructure. Peripheral areas may then lose workers and investment. However, new transport links, resource development or government policies can redirect growth.

Core and periphery are relative terms. A national core can still contain deprived neighbourhoods. Likewise, a peripheral region may include a prosperous tourism centre, mining zone or regional city.

Megacity growth

A megacity is an urban agglomeration with at least 10 million inhabitants. Megacity growth can result from:

• voluntary internal migration;
• natural increase within the existing urban population;
• the outward expansion of the built-up area;
• the incorporation or reclassification of nearby settlements.

Megacities often develop into major national cores, concentrating infrastructure, political influence and higher-order economic activity. Their growth may strengthen connections across the country, but it can also increase the gap between the dominant city and peripheral regions.

Two contrasting detailed examples

Two examples should demonstrate how population is unevenly distributed in different national settings. Taken together, they should identify:

• the location of dense and sparse population areas;
• relevant physical and human influences;
• links between population distribution and economic development;
• internal migration flows;
• the role of a core, peripheral regions and any megacity;
• how the pattern has changed over time.

The examples need to be genuinely contrasting. For instance, they could differ in income classification, physical environment, settlement history or the strength of one dominant urban core.

Australia offers a brief illustration. Most of its population is concentrated in coastal urban regions, particularly in the east and southeast, while much of the dry interior is very sparsely populated. Aridity and limited water restrict inland settlement. By contrast, coastal cities draw population because they concentrate employment, services, transport links and migration. This remains only an illustration; the two detailed examples used in class should provide the required evidence and comparison.

Judging relative importance

No single influence can explain where people live. Relative importance means deciding which factors have the greatest effect in a particular place, at a particular scale and time.

Physical factors often set broad limits. Water availability, climate and relief help explain why some regions of the world support far more people than others. Within these broad patterns, human factors often account for finer differences. Employment, transport, political decisions and technology can draw people towards particular cities and corridors.

The factors interact too. A river valley may provide water and fertile land, but high population density develops only when people can take advantage of them through farming systems, transport, investment and political stability. In the same way, a mineral deposit leads to lasting settlement only if it is accessible, profitable and connected to labour and markets.

Their importance can shift over time. Technology may reduce a physical constraint, while conflict can turn a previously attractive place into an unsafe one. Economic restructuring may weaken an old industrial core. New infrastructure, meanwhile, may improve the position of a peripheral region.

Scale and place

The main explanation depends on the scale being studied:

• Global scale: climate, major landforms, water availability and the broad geography of economic development help explain continental concentrations and sparse zones.
• National scale: core–periphery patterns, government policy, internal migration and the location of major cities become more visible.
• Local scale: housing costs, employment sites, transport routes, environmental quality and access to services may affect the exact neighbourhood in which people live.

A factor that seems weak at one scale may prove decisive at another. For example, national population density can hide a strong local concentration around a capital city or transport corridor.

Spatial interactions between places

Spatial interaction is movement or connection between places. This includes flows of people, goods, capital and information.

Such flows connect origins and destinations across different scales. Daily commuting links neighbourhoods to employment centres. Internal migration connects peripheral regions with national cores, while international trade and investment link national economies to global markets.

Interaction tends to be stronger between accessible, well-connected places. Distance, travel cost, borders and poor infrastructure can restrict flows. Transport routes, digital communication, shared language and established migrant networks can increase them. These interactions may reinforce uneven development as people and investment gather in an existing core. They can also spread opportunities through remittances, new infrastructure and connections to wider markets.

Geographic skills

Population and development patterns can be investigated by:

• reading direction, scale, political units and spatial patterns from maps;
• comparing choropleth, dot and proportional-symbol maps without confusing total population with population density;
• calculating density, percentages, ratios and ranges from population data;
• identifying concentrations, clusters, corridors, outliers and changes over time;
• comparing evidence at global, national and local scales before judging the relative importance of different influences.