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Central America — a region of the North American continent that includes all countries between Mexico in the north and Panama in the south inclusive Central Business District — the main commercial, financial and retail area of a town or city. The CBD is often the site of initial settlement and with ready access to transport and communication links for the efficient transfer of goods, services and information central place — an urban centre that serves communities in its surrounding hinterland providing central goods and services central place theory — in the early 1930s an economic geographer, Walter Christaller, proposed an idea to explain the spatial arrangement of urban places across the landscape. He stated that urban centres, called central places, would provide goods and services to their hinterland. However those larger urban places providing higher order goods would have greater trading areas because people would be willing to travel greater distances to purchase such goods. As a result urban places would be located at distances reflecting the threshold population needed to support goods and services being provided by the central place. The range of these goods and services determines the trading area of that central place. These trading areas, in turn, are influenced by the range of the goods and services provided. Those centres with small threshold populations and small ranges will be more common and spaced more closely together; while those with large threshold populations and large ranges will be much fewer in number and spaced more widely apart. In this way a hierarchy of settlements develops. The theory is very unrealistic because of the many assumptions that have to be made such as central places located
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The New Geography Dictionary
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on a flat plain with no variation. We know however that such features as hills and rivers can influence the size and spacing of settlements (see high order goods) centrally planned economy — an economic system where the factors of production (land, capital, labour and entrepreneurial skill), marketing, distribution and consumption are controlled by a central government. Examples of Centrally Planned Economies are former communist China and Cuba centrifugal force — a force that encourages people and economic activity to leave an area; for example pollution, traffic congestion, transport costs – also called push factors. These forces also contribute to the process of counterurbanisation centripetal force — a force that attracts people or economic activity into an area (eg tax incentives, access to infrastructure, employment opportunities and educational facilities) — also called pull factors CFCs — Chlorofluorocarbons. A range of compounds of carbon, chlorine and fluorine. CFCs are used as refrigerants in fridges, freezers and air conditioners but also in plastic foams that make up many disposable cups and packaging. When released into the atmosphere the molecules that make up the CFC are split by ultraviolet radiation from the sun. This releases atoms of chlorine that attack the ozone molecules in the Stratosphere, leading to a thinning of the ozone layer, allowing increased amounts of potentially harmful ultraviolet light to reach the surface of the Earth (see Ozone Hole) chain migration — movement of people (migration) from a village to a large city in a series of steps; eg from a village to a smaller town, a larger town, a large city Chandler Wobble — the variation in the rotation of the Earth due to a slight wandering of the poles relative to the