Ullman’s Spatial Interaction Model AP Human Geography (for composition book)

Travel patterns for purchase of clothing and yard goods Travel patterns for purchase of clothing and yard goods. A) Canadian rural cash-economy. B) Canadian older Mennonite sect. Very different travel behaviors show the differences that may exist in the “action spaces” of different cultural groups occupying the same territory. Getis, Getis, Fellmann

Getis, Geits, Fellmann Chicago Travel Patterns: shows 96% of all trips. What factors influence & create these patterns of interaction?

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 OiL

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. B C A

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.