1. Central Place Theory
Walter Christaller developed the Central Place theory to explain the size and spacing of cities that specialize in selling goods and services.
The theory consists of two basic concepts:
1) threshold -- the minimum market needed to bring a firm or city selling goods and services into existence and to keep it in business
2) range -- the average maximum distance people will travel to purchase goods and services Normally, the threshold is found within the range, as the diagram shows.

2. In 1933, German geographer Walter Christaller, published his Central Place theory (CPT).
This theory basically involved the theoretical distribution of settlements given ideal conditions. He noticed that towns of a certain size were roughly equidistant, and around these towns were smaller towns.

3. Central Place Theory
He proposed a model based on an isotropic plane and a universal transport network, assuming that the smaller towns would form hexagons around the larger ones.
These small towns would in turn have smaller villages in hexagons around them, and so on.

5. Can you think of examples from the past in Europe and from the United States today in which the range is larger than the threshold yet businesses thrive and market towns temporarily come alive?
Itinerant merchants in medieval Europe who would sell their wares in a different town each day or two to "collect" sufficient "ranges" to meet or, hopefully, exceed their "threshold" (market) to keep their business going
First Monday in Canton, Tx.
Traders Village

6. In the US, multi-million dollar businesses have insufficient thresholds because the range for their products are too small; hence, professional athletic teams and popular entertainers with their high income demands travel throughout the country collecting "ranges."

7. In the 21st century, how is this concept being taken to a new level?
Increase your personal “range” and “threshold”.

8. Central Place Theory
A Central Place is a settlement which provides one or more services for the population living around it.
Specialized services (e.g. universities, financial centers) are said to be of high order. Having a high order service implies there are low order services around it, but not vice versa.

9. Simple basic services (e. g
Simple basic services (e.g. grocery stores, service stations) are said to be low order settlements.

10. 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.

11. Factors affecting a fall in the threshold population are a decrease in population , change in tastes, income, and the introduction of substitutes.

12. Conclusions That Can be Made About Central Places
The larger a settlement, the farther away a similar size settlement is.
The Range increases as the population increases while the threshold may decrease physically.

13. The larger the settlement, the higher the order of its services.

14. Deviations to this rule are:
Tourist resorts that have a small population but large number of functions.

15. Dormitory towns that have a large population but a small number of functions.

16. Note that the area represented by a threshold varies with the density of population, while the range is a distance (or time.)  In areas with very sparse population, it’s conceivable that some goods won’t be offered at all:  the threshold required for providing the service is greater than the range for enough people to support it.
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17. Rank Size Rule and Primate City
The Rank Size Rule notes the relationship between the ranks of cities and their populations.
It was advanced by Zipf in 1941
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.

19. 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

20. Urban Morphology
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. Bid Rent Theory Diagram Factors Influencing Land Values
Proximity to a secondary shopping center.
Local Site Characteristics
Government Policy
Security
Functional Zones Within a City
The CBD is the central, most accessible, most expensive part of a city The Inner City is the area immediately surrounding the CBD. It has adverse social and economic conditions The Industrial Zone The Residential Zones. These are divided in 3 groups: Low Income: 1st generation immigrants and poorer groups.
Middle Income: 2nd generation immigrants, and wealthier groups.
High Class Residential: The wealthiest groups

21. Gravity model is the same as a functional unit – stores or cities

22. The popularity of a beach can be derived by applying Central Place Theory.
Picture a certain length of beach in summer, with a limited amount of sunbathing space. At dawn it's empty, and then slowly people arrive. It is human nature to try to sit as far apart as possible, so as not to be disturbed, but without having to do excessive walking. The first wave of early birds will therefore spread out to equidistant positions. Observations have shown that this typically results in people arranged in a straight line at ten metre intervals along the beach. The next wave of bathers, arriving after the first order bathers have taken their places, will place themselves between the first line but either higher or lower up the beach, forming the classic Christalle triangle/hexagon pattern. Subsequent waves will place themselves in the gaps, forming third and fourth level geometric shapes. Analysis of these shapes will determine the level of beach popularity over the course of a day or season.
It must be recognised that certain factors can skew the nice geometric shapes generated by the theory. Rocks, tides, topless girls, hunky lifeguards and noisy children will all have their effect. These can be noted and computer models used to correct for them.