GEOG 217 Lecture Notes - Lecture 3: Interaction Model, Effective Demand, Central Place Theory
18 May 2018
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Lecture 3 – January 15th
• Trade Relationships are sticky
o People have stable trade patterns - trade on a regular basis
• Telecommunications are directional
o Spatial aspect of things don’t matter as much anymore
o Not completely random. There are patterns e.g. east west axis
• Uneven distribution of things
o Flows because things are not distributed homogeneously throughout space
o There is heterogeneity
• Spatial interaction (Fellman Ch. 3)
o Defined: Movements of people's, ideas, and commodities within and
between areas or in space
Ullman's Spatial Interaction Model
• Spatial interaction model - Originally designed to describe trade flows between
regions
• Idea that spatial interaction is controlled by 3 conditions:
o 1. Complementarity
▪ One place has a supply of something for which there is effective
demand in the other (desire, purchasing power. Means for
transportation)
▪ Natural Differences
• E.g. Mexico has hot beaches and Canada doesn’t and desires
warm beaches and they have purchasing power so Canadians
go to Mexico for holidays
▪ Manufactured Differences
• The international division of labour
▪ Economies of Scale
• Cost per unit output decreases with total quantity produced so
they specialize in those goods
o 2. Transferability
▪ Acceptable cost of exchange, relationship between value of good and
cost of transportation
▪ Time space convergence: rate at which places move closer to each
other in space
o 3. Intervening opportunity
▪ No better alternatives
▪ Competitive opportunities may reduce interactions
• Formal models of spatial interactions [understand concepts]
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Lecture 3 january 15th: trade relationships are sticky, people have stable trade patterns - trade on a regular basis, uneven distribution of things, spatial interaction (fellman ch. 3: telecommunications are directional, not completely random. Ullman"s spatial interaction model: spatial interaction model - originally designed to describe trade flows between regions. Idea that spatial interaction is controlled by 3 conditions: 1. Complementarity: one place has a supply of something for which there is effective, natural differences demand in the other (desire, purchasing power. Transferability: acceptable cost of exchange, relationship between value of good and cost of transportation, time space convergence: rate at which places move closer to each other in space, 3. New inspirations: example: el nino teleconnections, localized conditions in the pacific that impact the americas as well as africa and asia, localized pattern having consequences very far away. Telecoupling framework: bathtub view vs. tele couplings (things are connected to each other and some are more important than others)
