The Community and Environment Spatial Analysis Center

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The Community and Environment Spatial Analysis
Center
Annual Washington URISA Conference February 7-8
2002
Monitoring Sprawl Eugene Martin
eugene_at_commenspace.org
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What is Sprawl?
"Perhaps diffusion is too kind of word. ... In
bursting its bounds, the city actually sprawled
and made the countryside ugly ..., uneconomic in
terms of services and doubtful social value."
Earle Sumner Draper - 1937
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Ten Characteristics of Sprawl

• Unlimited outward extension
• Low-density residential and commercial
  settlements
• Leapfrog development
• Fragmentation of powers over land use among many
  small localities
• Dominance of transportation by private automotive
  vehicles
• No centralized planning or control of land-uses
• Widespread strip commercial development
• Great fiscal disparities among localities
• Segregation of types of land uses in different
  zones
• Reliance mainly on the trickle-down or filtering
  process to provide housing to low-income
  households

Policy Analyst Anthony Downs - 1998
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What are the costs?
Loss of a "Sense of Place" Land Consumption
Threat to Farmland
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What are the costs?
Providing utilities is expensive
Dependence on the Automobile ( traffic jam)
Health Impacts
Environmental Impacts
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How can we detect or measure sprawl?
Is the urban landscape heterogeneous?
Street layout street edge
Parcel size and configuration
Accessibility of goods and services
Population Density
Impervious Surfaces
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Population Density (People Per Acre)
0 1 Rural
1 5 Sprawl
5 12 Pre Transportation Density
12 40 Transportation Density
40 and up Walking Density
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Measuring Density
Number of people / Area
Census blocks are variable in size
Census blocks are not always uniform
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Measuring Density
How many people live in how big an area?
The census block bounds should not be a
barrier to measuring density.
Solution Variable area density measures in a
raster environment
How far do I have to go to find 500 people?
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Measuring Density
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Changes in Density
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Measuring Impervious Surfaces
Spectral Mixing Analysis on Landsat Imagery
Pre-established set of image endmembers
Measure percent composition of each endmember in
each pixel
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Filtering for correction
Heterogeneity mask variability in a kernel
Size and compositional uniformity of road
interior areas
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Measuring Change
Change in impervious gt 35
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Comparing Sprawl patterns inSeattle, Portland
and Vancouver BC
Two chapters in a new book by
www.northwestwatch.org
Forthcoming March 2002
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Eugene Martin206 749 0112www.commenspace.orgeu
gene_at_commenspace.org
Questions?
This presentation is available on-line
athttp//www.commenspace.org/papers/waurisa/feb_
7_02.ppt