Spatial economics and location theory –
implications for modeling environmental
impacts of future development patterns
Brian Voigt
NR385 – Ecological Economics
Early City Development?
• Agricultural surplus
– technological innovation: irrigation, plow
• The defensive city
– fortified storage facility
• The religious city
– worship on a grander scale
– scale economies in the provision of religion
A Brief History of Location Theory
• David Ricardo (1772 – 1823)
– theory of differential rent based on variation in fertility
• J-H von Thünen (1738 - 1850)
– model based on a central market place with varying land uses
radiating outward
• Walter Christaller (1893 – 1969)
– theory of central place defined by hexagonal pattern based on
top-down approach
• August Lösch (1906 – 1945)
– bottom up approach modeled after Christaller
• William Alonso (1933 – 1999)
– model of demand for land as a function of distance from CBD
– locus of opportunities v indifference surface
von Thünen’s Isolated State
A Brief History of Location Theory
• David Ricardo (1772 – 1823)
– theory of differential rent based on variation in fertility
• J-H von Thünen (1738 - 1850)
– model based on a central market place with varying land uses
radiating outward
• Walter Christaller (1893 – 1969)
– theory of central place defined by functions of cities
– hexagonal pattern based on top-down approach
• August Lösch (1906 – 1945)
– bottom up approach modeled after Christaller
• William Alonso (1933 – 1999)
– model of demand for land as a function of distance from CBD
– locus of opportunities v indifference surface
Christaller & Lösch
Villages at vertices
Town =
City =
Conurbation =
A Brief History of Location Theory
• David Ricardo (1772 – 1823)
– theory of differential rent based on variation in fertility
• J-H von Thünen (1738 - 1850)
– model based on a central market place with varying land uses
radiating outward
• Walter Christaller (1893 – 1969)
– theory of central place defined by hexagonal pattern based on
top-down approach
• August Lösch (1906 – 1945)
– bottom up approach modeled after Christaller
• William Alonso (1933 – 1999)
– Location and Land Use (1964)
– model of demand for land as a function of distance from CBD
– locus of opportunities v indifference surface
Evolution Of Urban Form
• Topographic constraints
– Ports and waterways (1840s)
• Walking city
– 2 mile radius = 1 hr walk from edge to center (pre-1850s)
• Transportation options
– Horse drawn and electric trolley – expanded ring to 5 miles around city,
linear development, empty space b/t trolley lines (1850s – 1900)
– Cars and buses – expanded ring to 10 mile, fill in between trolley lines,
primarily auto dependent (1930s)
• Decentralization of the central city
– Redefining the American dream – post-WWII development of the 1940s
– Suburban, ex-urban, and edge cities
– Sprawling development
City Statistics
• 1950: 70% of population lived in cities
• 2000: 60% of population lived in suburbs
• Of the 157 urbanized areas in 1950
– 69 million people and 12,715 sq miles
• Same 157 urbanized areas in 2000
– 155 million people and 52,388 sq miles
• Net result
– 2.25 x population
– 4.12 x land area
Factors of Influence on Urban Form
• Social factors
– segregation – racial, class, religious
– congestion
• Economic
– maximizing individual satisfaction (Alonso, 1964)
– cheap land and subsidized transportation costs
• Technological change
– transportation
– telecommunication – substitute for human
interaction?
• Government policy
– Federal – highways, water & sewer
– State & local – land use planning
Land Use Planning
• Originated in the 1920s as a means to protect
human health and welfare from neighboring
industrial development
– Can we protect people from themselves?
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•
Segregation of land uses
Causes and characteristics of sprawl
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–
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affordable transportation, federally funded highways
affordable home mortgage rates post WWII
low density, non-contiguous land patterns
Can we plan our way out of sprawl? Portland v
Phoenix
Modeling with UrbanSim
• University of Washington, Dept of Urban Design and Planning
– www.urbansim.org
• Dynamic disequilibrium approach
– avoid oversimplification of general equilibrium conditions
• perfectly competitive market, products are homogenous, resources are
mobile, present and future costs are known to all
• Actor adjustment processes occur at varying rates
– short: travel behavior
– medium: household / business location
– long: real estate development
• Simulates annual evolution of households, jobs and real estate
– individual-based for household and employment location
– grid-based real estate market
• Allows for hypothesis testing on specific policy alternatives or impact
evaluation of scheduled events
from Waddell, et al, 2003
UrbanSim cnt’d
• Model architecture
– suite of tools that interact through a data store
– each component is recalculated annually
– exogenous inputs
• macroeconomic model predicts future conditions based on logistic regression
analysis
• travel demand forecasts future travel conditions
• user input – changing land use policy, scheduled events
• Model components
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–
–
–
–
–
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accessibility – normal good w/positive economic value
economic transition – distribution of jobs through employment sectors
demographic transition – distribution of households by type over time
employment mobility – P(job moves from one location to another)
household mobility – P(household moves from one place to another)
employment location – P(new or relocated job, located at a particular site)
household location – P(new or relocated household, located at particular site)
from Waddell, et al, 2003
Applying UrbanSim to Northern VT
Data
• Economic
– land value, employment
• Biophysical
– topography, soils
• Infrastructure
– roads, transit
• Planning & zoning
– land use, available housing
• Census
– population, household
income, race, age
Case example
• Chittenden, Addison and
Lamoille Counties
• Model calibration
– 1990 – 2002
• Model run
– 2000 – 2015
• Coordinated research
effort:
– habitat fragmentation
– northern forest research
– EPA grant
Model Outputs – Land Use
Change: 1980 - 1994
Conclusions
• Variation from early theories
– global market place
– changing technology
• Utility of current modeling effort
– model outputs inform planning process & ecosystem
modeling
– export to GIS for spatial analysis and visualization
• Relevance to land use planning
– assess impacts of current development patterns on
environmental quality
• test impacts of alternative land use policies
• improved alternative to current growth model
– minimize habitat fragmentation, enhance restoration,
and protect species biodiversity
"… we have been the most prodigal of people with land, and for
years we wasted it with impunity ... no matter how much we fouled
it, there was always more over the next hill, or so it seemed."
William Whyte (1968), The Last Landscape