Editing Urban structure

[[File:Aerial view of central Erbil, Kurdistan.jpg|thumb|360px|The city of [[Arbil]] in the Kurdistan Region of Iraq has a radial urban structure centred on an ancient fortress]]

'''Urban structure''' is the arrangement of [[land use]] in [[urban area]]s, in other words, how the land use of a city is set out.<ref>{{cite web | title=BBC - Standard Grade Bitesize Geography - Urban structure and models : Revision | website=bbc.co.uk | date=2013-04-20 | url=https://www.bbc.co.uk/bitesize/standard/geography/settlement/structure_models/revision/1/ | archive-url=https://web.archive.org/web/20130420163519/http://www.bbc.co.uk/bitesize/standard/geography/settlement/structure_models/revision/1/ | archive-date=2013-04-20 | url-status=dead | ref={{sfnref | bbc.co.uk | 2013}} | access-date=2019-04-01}}</ref> [[Urban planner]]s, [[economist]]s, and [[geographer]]s have developed several models that explain where different types of people and businesses tend to exist within the urban setting. Urban structure can also refer to '''urban spatial structure''', which concerns the arrangement of [[public space|public]] and private space in cities and the degree of [[Permeability (spatial and transport planning)|connectivity]] and accessibility.

==Zonal model==
{{main|Concentric ring model}}

This model was the first to explain distribution of social groups within urban areas. Based on one single city, [[Chicago]], it was created by sociologist [[Ernest Burgess]]<ref>Burgess E.W. (1924)"The growth of the city: an introduction to a research project" Publications of the American Sociological Society, 18:85-97</ref> in 1924. According to this model, a [[city]] grows outward from a central point in a series of [[concentric]] rings. The innermost ring represents the [[central business district]]. It is surrounded by a second ring, the zone of transition, which contains industry and poorer-quality housing.  The third ring contains housing for the working-class and is called the zone of independent workers' homes.  The fourth ring has newer and larger houses usually occupied by the [[middle-class]]. This ring is called the zone of better residences. The outermost ring is called the [[commuter]]'s zone. This zone represents people who choose to live in residential [[suburb]]s and take a daily commute into the CBD to work.

==Sectoral model==
{{main|Sector model}}

A second theory of urban structure was proposed in 1939 by an economist named [[Homer Hoyt]].<ref>Hoyt H (1939): "The structure and growth of residential neighborhoods in American cities" Washington DC; Federal Housing Administration</ref> His model, the sector model, proposed that a city develops in sectors instead of rings. Certain areas of a city are more attractive for various activities, whether by chance or geographic and environmental reasons. As the city grows and these activities flourish and expand outward, they do so in a wedge and become a sector of the city. If a district is set up for high income housing, for example, any new development in that district will expand from the outer edge.

To some degree this theory is just a refinement on the concentric model rather than a radical restatement.  Both Hoyt and Burgess claimed [[Chicago]] supported their model.  Burgess claimed that Chicago's central business district was surrounded by a series of rings, broken only by [[Lake Michigan]]. Hoyt argued that the best housing developed north from the central business district along Lake Michigan, while industry located along major rail lines and roads to the south, southwest, and northwest.

[[Calgary, Alberta]] almost perfectly fits Hoyt's sector model.

==Multiple nuclei model==

{{main|Multiple nuclei model}}

Geographers [[Chauncy Harris]] and [[Edward Ullman]] developed the multiple nuclei model in 1945.<ref>Harris C D and Ullman E L (1945), "The nature of cities" Annals of the American Academy of Political and Social Science 242: 7-17</ref>  According to this model, a city contains more than one center around which activities revolve.  Some activities are attracted to particular nodes while others try to avoid them. For example, a university node may attract well-educated residents, pizzerias, and bookstores, whereas an airport may attract hotels and warehouses. Other businesses may also form clusters, sometimes known locally as [[wikt:iron triangle|Iron Triangle]]s for automobile repair or [[red light district]]s for prostitution, or [[arts district]]s. Incompatible activities will avoid clustering in the same area, explaining why heavy industry and high-income housing rarely exist in the same neighbourhood.

==References==
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{{DEFAULTSORT:Urban Structure}}
[[Category:Urban geography]]
[[Category:Urban planning]]
[[Category:Urban design]]