Theories of urbanization include; sector, multiple-nuclei, concentric zone, conflict and peripheral theories.
This article discusses some theories of urbanization, as follows;
1). Sector Theory of Urban Growth (as one of the Theories of Urbanization)
The sector theory of urban growth was proposed in 1939 by economist Homer Hoyt, in a bid to develop a reliable model by which the development of cities can be understood .
According to the sector theory, urban development tends to occur in terms of distinctive sectors or components of the urban ecosystem, so that the individual growth of these sectors leads to collective advancement of urban areas .
It can be viewed as a contrary perspective to that of the concentric zone theory, which provides a more unified and holistic portrayal of urban development.
The sector theory of urban growth is highly applicable in both geographic and economic contexts. Sector models usually include a centric component that defines the point of unison of the various sectors (often portrayed as pie-shaped wedges) occurring in an urban ecosystem.
‘Sectors’ of the urban ecosystem represent the different industries, socioeconomic groups, policies, stakeholders and resources that work both individually and collaboratively to sustain and increase urbanization.
2). Multiple-Nuclei Theory
The multiple-nuclei theory and model were proposed by geographers Chauncy, D. Harris and Edward, L. Ullman in the year 1945, in a bid to describe urbanization from a basic developmental perspective .
It can be seen therefore to share similar role and purpose to the sector theory of urban growth, as both concepts are designed to analyze how urban areas develop.
The multiple-nuclei theory states that urbanization does not emanate or progress from a single, traceable point or nucleus; but is rather the product of multiple simultaneous growth processes around various nuclei within a single geographic area
One of the objectives of the multiple-nuclei theory is to debunk the concept of a singular, Central Business District (CBD), which is believed to be the focal point of urban growth in other theories of urbanization (including the sector theory).
As such, the multiple-nuclei model features more than one nucleus, or CBD in an urban region.
Pros of the multiple-nuclei model include its versatility, adaptability and applicability for analysis of urban development at any given stage and in any geographic context.
On the other hand, cons of the multiple-nuclei model include its relative complexity and tendency to fragment a given urban scenario into irreconcilable segments.
3). Concentric Zone Theory (as one of the Theories of Urbanization)
The concentric zone theory is based on the Burgess model, proposed in 1925 by sociologist Ernest Burgess .
It states that urban expansion, growth and development occur in concentric circles that surround a CBD core, from which most of the regional industrialization emanates.
The Burgess model tells us that the cost of resources, as well as the living conditions and general economic activity level at any location in an urbanized area, all depend on the distance of that location from the CBD; where living cost tends to reduce with increase in distance from the CBD.
The concentric zones or rings represent various levels of sociological and geographic distance from the CBD.
They are often five in number, identified from the center outward as follows;
1). Central business district (CBD)
2). Zone of deterioration
3). Zone of workingmen’s homes
4). Residential area
5). Commuter’s zone
Concentric zone theory is especially applicable and important for urbanization concepts that are relatively simple and which involve significant economic activity.
It may also be used to evaluate how the degree of urbanization changes with distance from the CBD or urban core.
4). Conflict Theory
The conflict theory of urbanization focuses on the occurrence and role of social and economic differences in the development, modification and control of urban areas.
A conflict theorist’s view on urbanization is based on conclusions that the middle and upper-class in urban societies, dictate the trend of development to suit their instantaneous needs, so that the dynamic of conflicts of interest plays a huge role in shaping cities.
Conflict theory is more focused on the political aspect of urbanization than other theories, and evaluates economic aspects only on the basis of how they influence, or are influenced by, political factors.
It is very useful for analyzing scenarios of complex political influence, and various forms of urban conflict.
5). Peripheral Theory (as one of the Theories of Urbanization)
The peripheral theory of urbanization portrays urban areas as decentralized and indefinite, based on the continuous creation of new urban space on the periphery of such areas.
Peripheral urbanism or urbanization is itself the establishment of urban spaces that are not directly influenced by adjacent urban areas or nuclei, thereby producing a heterogeneous outlay of auto-constructed metropolises .
The peripheral theory is important for describing sub-urbanism, as well as the variations in resource distribution, sociocultural tendencies, and quality of life, within an expansive urban sprawl.
Theories of urbanization are;
1. Sector Theory of Urban Growth
2. Multiple-Nuclei Theory
3. Concentric Zone Theory
4. Conflict Theory
5. Peripheral Theory
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