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March 25, 2004
NASA Uses a “SLEUTH” to Predict Urban Land Use
According to NASA-funded researchers, developed land in the greater
Washington-Baltimore metropolitan area is projected to increase 80 percent
by 2030. Scientists used a computer-based decision support model loaded
with NASA and commercial satellite images to simulate three policies
affecting land use.
The researchers, Claire Jantz and Scott Goetz, from the University of
Maryland, College Park, Md., and the Woods Hole Research Center, Woods
Hole, Mass., also found a 39 percent increase in developed land in the
region from 1986 to 2000. Some of the most striking changes occurred
around the Dulles Airport area in Northern Virginia.
Observations from NASA and commercial Earth observation satellites were
used in a United States Geological Survey (USGS) computer model, called
SLEUTH. The model was applied to 23,700 square kilometers (9151 sq. miles)
of the Washington-Baltimore metropolitan area. The initial aim was to
simulate the impact of future policy scenarios on the area and Chesapeake
Bay watershed. “The satellite observations provided us with an
unprecedented ability to monitor the urbanization process and capture
the patterns of urban sprawl,” Goetz said.
The study is in the March issue of Environment and Planning B. It explains
how models may be used to forecast the effects of urban growth and runoff
on the Chesapeake Bay estuary system.
The study showed how high resolution commercial imagery from Space Imaging’s
IKONOS satellite can be used to complement NASA’s imagery from
Landsat satellites. IKONOS images, with resolutions up to one meter (3.28
feet), were used with county-level air photos to link to 30-meter Landsat
observations, which cover vast areas and offer a longer time frame for
assessing urban change.
The project was designed to study declining water quality in the Chesapeake
Bay estuary due in part to disruptions in the hydrological system caused
by urban and suburban development. The goal was to create a modeling
system that could assess future development and support decision making
by exploring the potential impact of different regional management scenarios.
Future growth was projected out to 2030 using three different policy
scenarios. The scenarios were based on current trends, managed, and ecologically
sustainable growth.
The current trends scenario simulated how the Washington metropolitan
area might change if development policies remained the same. This scenario
included forest and agricultural preservation already in place, leaving
unprotected areas open for development. In this scenario, development
increased by 80 percent by 2030.
The managed growth scenario assumed added protection of forests and
agriculture areas and placed moderate growth boundaries around already
built areas. In this scenario, development increased by 30 percent by
2030. In the ecological scenario, strong protection of most forests and
agricultural areas was projected, so development only increased by 20
percent by 2030.
“The model is a tool that can be used for land use planning and
resource management,” Jantz said. “It offers the ability
to explore and visualize alternative futures.”
The model is applicable to land use studies, and it has small to large-scale
potential. It can also help decision- makers assess the configuration
of landscapes in forests and urban areas, and understand sources of runoff
related to water quality in streams. The Maryland Department of Natural
Resources is exploring use of the model to target forest resources, restoration
and conservation activities.
NASA’s Earth Science Enterprise is dedicated to understanding
the Earth as an integrated system and applying Earth System Science to
improve prediction of climate, weather, and natural hazards using the
unique vantage point of space. NASA funded the study, with additional
funds from the Chesapeake Bay Foundation.
For information about NASA programs and research on the Internet, visit:
http://www.nasa.gov
For information about this study and images on the Internet, visit:
http://www.gsfc.nasa.gov/topstory/2004/ 0322sleuth.html
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Contacts:
Elvia H. Thompson
Headquarters, Washington
Phone: 202/358-1696
Krishna Ramanujan
Goddard Space Flight Center, Greenbelt, Md.
Phone: 607/273-2561 |
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Study Area Within Chesapeake Bay Watershed
This image shows the greater Washington-Baltimore metropolitan study
area within the Chesapeake Bay watershed. Credit: Claire Jantz
High-Resolution Image
Urban growth in Washington DC, 1986-2000
These satellite images of impervious surface data are an indication of
the 39% increase in developed land in the Washington DC metropolitan
area between 1986 (top) and 2000 (bottom). These images were derived
from Landsat data fitted with an algorithm that illuminates changes in
low-density residential land use, exemplifying sprawl. Impervious surfaces
are shown in yellow, orange, and red.
Credit: NASA/USGS
Urban growth in Baltimore, 1986-2000
These satellite images of impervious surface data are an indication of
the 39% increase in developed land in the Baltimore metropolitan area
between 1986 (top) and 2000 (bottom). These images were derived from
Landsat data fitted with an algorithm that illuminates changes in low-density
residential land use, exemplifying sprawl. Impervious surfaces are shown
in yellow, orange, and red. Credit: NASA/USGS
Developed Areas Between 1986 and 2000 Near Dulles Airport
This image shows change in developed areas between 1986 and 2000 near
Dulles airport in northern Virginia. Black shows the extent of development
in 1986, blue shows new development in 1990, yellow indicates new development
in 1996 and red shows the extent of development in 2000. Credit: Claire
Jantz
High-Resolution Image
Forecast of Development Patterns in 2030 for Current Trends Scenario
This image shows the forecast of development patterns around the greater
Washington-Baltimore metropolitan area in 2030 in a scenario where current
trends continued as they are now. This scenario included forest and agricultural
preservation already in place, leaving unprotected areas open for development.
When current trends remained, development increased by 80 percent by
2030. Credit: Claire Jantz
High-Resolution Image
Forecast of Development Patterns in 2030 for Managed Growth Scenario
This image depicts the forecast of development patterns in 2030 for a
managed growth scenario. The managed growth scenario assumed added protection
of forests and agriculture areas and placed moderate growth boundaries
around already built areas. In this scenario, development increased by
30 percent by 2030. Credit: Claire Jantz
High-Resolution Image
Forecast of Development Patterns in 2030 for Ecologically Sustainable
Scenario
This image shows the forecast of development patterns in 2030 for an
ecologically sustainable scenario. In the ecological scenario, when strong
protection of most forests and agricultural areas was projected, development
only increased by 20 percent by 2030. Credit: Claire Jantz
High-Resolution Image
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