Ullman’s Spatial Interaction Model

AP Human Geography

(for composition book)

Travel patterns for purchase of clothing and yard goods. A) Canadian rural cash-economy. B) Canadian older Mennonite sect.

Getis, Getis, Fellmann

Very different travel behaviors show the differences that may exist in the “action spaces” of different cultural groups occupying the same territory.

Chicago Travel Patterns: shows 96% of all trips.

What factors influence & create these patterns of interaction?

Getis, Geits, Fellmann

Edward Ullman’s Theory

Spatial Interaction is controlled by three flow-determining factors.

1. Complementarity

2. Transferability

3. Intervening Opportunity

Complementarity For two places to interact,

one place must have a supply of an item for which there is an effective demand.

Example: product: Oil - Interaction: US - Middle East

What is Effective Demand?

Desire for the item (demand)

Purchasing Power - $$$

Means to transport the product - rail, road, internet, ship etc.

Transferability

Refers to mobility of a commodity

Spatial interaction occurs only when acceptable costs of an exchange are met.

Costs include both Time and Money

Transferability Function of Three Conditions.

Characteristics and value of product. The distance measured in time and money. The ability of the commodity to bear the costs of movement.– Both physical and economic.– If the time and money costs are too great

interaction does not occur.– Buyer seeks substitute or goes without product.

Intervening Opportunity

Closer opportunities will reduce the the attractiveness of interaction with more distant- even slightly better- alternatives.

Example -ski area in Big Bear. The snow is not as good as Tahoe. But people in Southern Calif. are more likely to ski in Big Bear.

A

B

C

Measuring Spatial Interactions

Key Concepts and Theories

-Friction of Distance

-Space time compression

Friction of Distance

Distance has a retarding effect on human interactions because there are increasing penalties in time and cost associated with longer distances.