Central Place Theory

“Models are not real, but help us understand reality”

Central Place Theory• Central Place: market center for

the exchange of goods and services by people attracted from the surrounding area

• Theory explains how services are distributed and why a regular pattern of settlements exists

• German geographer Walter Christaller (1930)

Note the regularity of spacing between urban centers -- towns. Local lore has it that the distances between towns evolved because it was the distance someone could travel in a day.

The Cumberland Valley of Pennsylvania is a portion of the Great Valley of the Appalachians. Broad valley floor, agricultural, settled in the early-to-mid 1700s

“If . . . “

• Isotropic Surface– “featureless plain” with no barriers to movement

• Even Population Distribution– similar in purchasing power and behavior

• Homo Economicus– “economic man” with purely economic motives

• Integrity of the Law of Supply and Demand– customers needed for a business to stay open

“Then . . . “

• There will be a regular spatial order in the number of central places of different population sizes.– Few large places– Many small places

• There will be a regular spatial order in the spacing of central places of different population sizes.– Large places relatively farther apart– Small places relatively closer together

Central Place FunctionsCategories of like services found in a

central place

• Grocery Stores• Gas Stations• Jewelry Stores• Book Stores• Hair Stylists• Auto Dealerships

• Houses of Worship• Schools• Doctors• Dentists• Museums• Concert Halls

Would you travel farther to buy a new car or the week’s groceries?

To buy a new car

Would you travel farther to go to elementary school or to go to high school?

Would you travel farther to see your family physician or a heart specialist?

To see a heart specialist

To go to high school

A Hierarchy of Educational

Services

Hamlet:No Schools

Village:Elementary

School

Town:High School

City:College

Stock Exchange

Sports Stadium

Regional Shopping Mall

Major Department Store

Income Tax Service

Convenience Store

Gas Station

How big is the trade area of a service center?

It depends on . . . - How far a consumer is willing to travel for the service- How many customers a service needs

Each central place function has a:

• Threshold: the minimum number of people needed to support a central place function

• With fewer customers a store cannot afford to stay in business.

• Range: the maximum distance beyond which a person will not travel to purchase a good or service

• Beyond a certain distance people cannot afford the travel costs.

Optimal Location (for Pizza Shop)

Fig. 12-6: 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).

Supermarket and Convenience Store Market Areas

Fig. 12-8: Market area, range, and threshold for Kroger supermarkets (left) and UDF convenience stores in Dayton, Ohio. Supermarkets have much larger areas and ranges than convenience stores.

Best Location in a Linear Settlement

Rank Size Rule George Zipf – 1949

• The country’s nth largest settlement is 1/n the population of the largest settlement

• 2nd largest city is ½ the largest

• 4th largest city is ¼ the size of the largest

Rank-Size Rule: United States

City Population

New York City 8,391,881

Los Angeles 3,831,868

Chicago 2,851,268

Houston 2,257,926

Phoenix 1,593,659

Philadelphia 1,547,297

San Antonio 1,373,668

San Diego 1,306, 300

Rank-Size Distribution of Cities

Fig. 12-9: 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 City Rule• The largest settlement

has more than twice as many people as the second-ranking settlement.

• Primate City=largest city

• Denmark– Copenhagen 1 million– Arhus 200,000

• United Kingdom– London 8 million– Birmingham 2 million

• Thailand– Bangkok 1.5 million– Nonthaburi 250,000