Why are Consumer Services Distributed in a Regular Pattern?

12.2

Central Place TheoryA central place like Orlando is a market center for the exchange of goods & services by people

attracted from the surrounding area.

Central place theory explains how services are distributed & why regular patterns of settlement

exist.

Market Area

Hexagons are often used to delineate market areas…Why?

The area surrounding a service from which customers are attracted is known as a market area or hinterland. In order to determine Market area you need to know RANGE and

THRESHOLD.

Range of a ServiceRange is the maximum distance people are

willing to travel for a service.

short distances for everyday services, long distances for other services. May be expressed

as time.

ThresholdThreshold is the minimum number of people

needed to support a service.

The median threshold needed to support this Kroger grocery store in Dayton, Ohio is about

30,000 people.

Demographics• Things to consider

– Age – Gender– Marital status– Children – Disabilities– Mobility– Race– Home ownership– Income– Employment status– Family size– Religion– Ethnicity– Religion– Education– Occupation

• Remember it is all about maximizing profits!!!

• SOOOOOOO…

• LOCATION, LOCATION, LOCATION

Gravity ModelThe gravity model predicts that the optimal location of a service is directly related to the number of people in the area and inversely related to the distance people must travel to

access it.

T

GIS can help companies determine

where to locate a new facility

using the gravity model

Best Location in a Linear Settlement

The optimal location for a pizza delivery shop with seven potential customers in a linear settlement (top) and with 99 families in

apartment buildings (bottom)… the median location is always the best.

Christaller’sCentral Place Theory

Market areas are arranged into a regular

pattern according to central place theory, with

larger settlements fewer and

further apart.

Rank-Size Distribution of SettlementsRank-size rule states that the 2nd largest city is

½ the size of the largest…the 4th largest city is 1/4th the size of the largest and so on…

Cities in the U.S. closely follow the rank-size

distribution, as indicated by the almost straight line on this log

scale. In Romania, there

are few settlements in

two size ranges.

Primate CitiesThe primate city rule states that the largest

settlement has more than twice as many people than the 2nd largest settlement.

Paris is an example of a Primate City because it has over 11 million people. The 2nd largest French city, Lyon,

has less than 2 million.

Found in more LDCs