From Academic Kids
fr:unité urbaineIn the study of human settlements, an agglomeration is an extended city or town area comprising the built-up area of a central place (usually a municipality) and any suburbs or adjacent satellite towns. Another term for agglomeration is urbanized area. However, because of differences in definitions of what does and does not constitute an 'agglomeration', as well as variations and limitations in statistical or geographical methodology, it can be problematic to compare different agglomerations around the world. It may not be clear, for instance, whether an area should be considered to be a satellite and part of an agglomeration, or a distinct entity in itself.
The Greater Tokyo Area provides an example of the difficulties involved because estimates of its population vary according to how it is defined. While the prefectures of Tokyo, Chiba, Kanagawa and Saitama are commonly used to define Greater Tokyo, the Japan Statistics Bureau simply measures the area within 50 kilometers of the Tokyo Metropolitan Government Offices in Shinjuku (http://www.stat.go.jp/english/data/handbook/c02cont.htm)  (http://www.citypopulation.de/World.html).
The term 'agglomeration' is distinct from a 'Conurbation', which is a more specific term for urban clusters where the built-up zones of influence of distinct cities or towns are connected by continuous built-up development. Each city or town in a conurbation may nevertheless continue to act as an independent focus for a substantial part of the area.
A metropolitan area is an extended agglomeration or conurbation that also includes peripheral areas not themselves necessarily urban in character but closely bound to the urban area by employment or commerce.
Businesses can also "agglomerate" when they need to be in close contact (eg. Financial Services)
- Economies of agglomeration
- Metropolitan Area
- World city
- Largest cities of the world - A list of the largest metropolitan areas by population
- Prinicipal Agglomerations of the World (http://www.citypopulation.de/World.html)
- Largest cities of the world (municipalities) (http://www.demographia.com/db-world-muni.htm)de:Stadtregion