Central Place Theory
At first glance, the pattern of the location of towns and cities appears
to be without order. In fact, there are a number of factors that tend to
cause order in apparent disorder.
Von Thünen, a German farmer writing in 1826, about where he
lived, suggested a town would locate at the centre of a productive area,
both to be supplied by the farms and to act as a service centre for the
farms.
Von Thünen’s main assumptions:
1) All land was flat and featureless.
2) The land is equally fertile everywhere
3) Transportation is equally accessible in all directions
4) There is no outside influence
5) All farmers are equally intelligent and ambitious
So, barring any physical obstacles or pathways, these service areas would
be circular. More towns would introduce zones of influence, or the area
that is serviced by an urban place, where they came into contact.
However, circular areas do not cover all land surface, so what about the
people living in between?
So, he tried overlapping circles.
To cover the whole service area and
not leave an area un-served, the range
circles must overlap. But consumers
can only shop in one place in this theory!
What is the spatial solution?
But this also does not work because they do not define clear service areas.
Another German by the name of Walter Christaller came along in
1935 and suggested that instead of circles to define zones of influence,
hexagons should be used. Christaller combined the ideas of hexagonal
service areas and differing thresholds to create what he called Central
Place Theory to explain the existence and location of urban centres.
Answer:
hexagons (six-sided shapes) that
completely cover an area without
overlapped or unserving any areas
The major characteristic of his theory is that small service centres
around villages are nested in larger service areas called towns and towns
are nested in still larger service areas called cities.
There is a relationship between how far one will go for a good or
service and the size of the town offering the good or service. This
relationship between urban size and the level of sophistication of available
goods and services is referred to as urban hierarchies.
Hierarchies exist because larger service areas are needed for more
specialized goods and services. The town must be large enough to have
enough potential sales in the areas served to cover operation costs and
provide a satisfactory profit.
Once this is met, a new threshold is said to have been met.
Threshold is the number of potential customers (sales) required before a
good or service can be successfully offered for sale.
For Example: A town of 25 000 might support 5 grocery stores, only 1
appliance store and a car dealership but not a Lamborghini sports car
dealership. (A threshold of several million people would be needed for the
latter)
Goods and services come in:
 Low order – (village) milk, bread, essential needs
o Requires minimum of 800 potential customers to be viable.
 Medium order - (town) appliances, stereo
 High order – (large town, small city) cars, carpet sales, furniture,
hospital
o Requires minimum 70,000 potential customers to be viable
 Very high order – (large city) specialized medical services, live
theatres, yacht sales
o Requires minimum 350,000 potential customers to be viable