Urbanisation is the process by which there is an increase in the proportion of people living in urban areas.
Some common indices used to define towns are
Level of administration
The UN has refused to classify settlements as towns/rural areas and has instead chosen to classify them by size.
The Growth of Towns and Cities
The earliest towns were around the Mediterranean Sea. Babylon is the oldest recorded town.
Urbanisation was a significant way of life in the Western World by 1AD
Before the industrial revolution, most towns were small and mainly commercial centers and seaports.
After the industrial revolution, cities grew very rapidly.
By 1850, there were 2 "million cities"(cities with a population exceeding one million)-London and Paris.
The growth of towns experienced a population explosion in the 1950s.
By 1990, there were 286 "million cities."
The Rank Size Rule
The Rank Size Rule notes the relationship between the ranks of cities and their populations.
It was advanced by Zipf in 1941
The formula is Pn=P1/n where Pn is the population of towns ranked n, P1 is the population of the largest town and n is the rank of the town.
For example, if the largest town has a population of x, the second largest town will have a population of x/2, the 3rd largest will have a population of x/3 and so on.
The Law of the Primate City
The primate city is the largest most dominant city in a region.
The degree of primacy refers to the dominance of the largest city over the rest of the country.
Most LDCs (Less Developed Countries) have a high degree of primacy while most MDCs (More Developed Countries) have a low degree of primacy.
Factors that affect high primacy include
Having an underdeveloped economy
Having an agriculturally dominant economy
A rapidly expanding population
A recent colonial history
The Central Place Theory (CPT)
A Central Place is a settlement which provides one or more services for the population living around it.
Simple basic services (e.g. grocery stores) are said to be of low order while specialized services (e.g. universities) are said to be of high order.
Having a high order service implies there are low order services around it, but not vice versa.
Settlements which provide low order services are said to be low order settlements. Settlements that provide high order services are said to be high order settlements.
The sphere of influence is the area of under influence of the Central Place.
The minimum population size required to profitably maintain a service is the threshold population.
Factors affecting a fall in the threshold population are
A decrease in population
Change in tastes
Introduction of substitutes
Conclusions That Can be Made About Central Places
The larger the settlements, the fewer their number
The larger a settlement, the farther away a similar size settlement is
The Range increases as the population increases
The larger the settlement, the higher the order of its services. Deviations to this rule are:
Tourist resorts that have a small population but large number of functions.
Dormitory towns that have a large population but a small number of functions.
Christaller made a number of assumptions such as:
All areas have
an isotropic (all flat) surface
an evenly distributed population
evenly distributed resources
similiar purchasing power of all consumers
The theory points out that to prevent spheres of influence overlapping or having gaps, the best shape was a hexagon.
The breaking point is where the consumer is equidistant from two/more similar services i.e. where the consumer is equally far from two or more centers.
The formula to calculate it is djk=dij/(1+Square Root of(Pi/Pj)) where djk is the distance from j to k, dij is the distance between two towns, Pi/Pj are the populations of j and i and i is the bigger town.
This is the distribution of different functions in a city
The Bid-rent Theory
The Bid Rent Theory suggests different functions will bid differently for land in various parts of the city.
It suggests the more accessible the site of land, the higher is its value.