Central place theory

Central place theory is a geographical theory that seeks to explain the number, size and location of human settlements in a residential system.The theory was created by the German geographer Walter Christaller, who asserted that settlements simply functioned as 'central places' providing services to surrounding areas.
Building the theory
#To develop the theory, Christaller made the following simplifying assumptions:
All areas have:
#an unbounded isotropic (all flat), homogeneous, limitless surface (abstract space)
#an evenly distributed population
#all settlements are equidistant and exist in a triangular lattice pattern
#evenly distributed resources
#distance decay mechanism
#perfect competition and all sellers are economic people maximizing their profits
#consumers are of the same income level and same shopping behaviour
#all consumers have a similar purchasing power and demand for goods and services
#Consumers visit the nearest central places that provide the function which they demand. They minimize the distance to be travelled
#no provider of goods or services is able to earn excess profit (each supplier has a monopoly over a hinterland)
Therefore, the trade areas of these central places who provide a particular good or service must all be of equal size
there is only one type of transport and this would be equally easy in all directions
transport cost is proportional to distance traveled in example, the longer the distance traveled, the higher the transport cost()
The theory then relied on two concepts: threshold and range.
Threshold is the minimum market (population or income) needed to bring about the selling of a particular good or service.
Range is the maximum distance consumers are prepared to travel to acquire goods - at some point the cost or inconvenience will outweigh the need for the good.
The result of these consumer preferences is that a system of centers of various sizes will emerge. Each center will supply particular types of goods forming levels of hierarchy. In the functional hierarchies, generalizations can be made regarding the spacing, size and function of settlements.
The larger the settlements are in size, the fewer in number they will be, i.e. there are many small villages, but few large cities.
The larger the settlements grow in size, the greater the distance between them, i.e. villages are usually found close together, while cities are spaced much further apart.
As a settlement increases in size, the range and number of its functions will increase .
As a settlement increases in size, the number of higher-order services will also increase, i.e. a greater degree of specialization occurs in the services.
The higher the order of the goods and services (more durable, valuable and variable), the larger the range of the goods and services, the longer the distance people are willing to travel to acquire them.
At the base of the hierarchy pyramid are shopping centres, newsagents etc. which sell low order goods. These centres are small. At the top of the pyramid are centres selling high order goods. These centres are large. Examples for low order goods and services are: newspaper stalls, groceries, bakeries and post offices. Examples for high order goods and services include jewelry, large shopping malls and arcades. They are supported by a much larger threshold population and demand.