Like many cities across the United States, the landscape
of Eagan, Minnesota is changing. Residents are building
new homes and the city is laying more roads and sidewalks.
The result is a city landscape dominated by pavement,
concrete and rooftops.
Research suggests that these
man-made, impervious surfaces - which include sidewalks,
driveways, rooftops and parking
lots - are largely responsible for decreasing water quality,
fish populations and groundwater reserves, and increasing
the likelihood of habitat fragmentation, flooding and
urban heat island effects. For this reason, environmental
analysts often examine the amount of impervious surface
in an area by referencing maps of impervious surface
derived from aerial
photographs or ground surveys.
With satellite imagery available that is comparable
in detail and increasingly affordable, the RSL has
worked in collaboration with the Metropolitan Council
of Minnesota to develop impervious surface maps for
the Twin Cities Metropolitan Area (TCMA) based on satellite
data. The TCMA totals about 3,000
square miles and comprises seven counties with a diversity
of land cover classes including high and low density
urban areas, small towns, cropland, forests and wetlands.
To date, RSL analysts have used two types of satellite
Landsate TM data (30-meter pixels) and high-resolution
IKONOS data (4-meter pixels).
Digital imagery captured
from sensors on earth observing satellites, such as
Landsat 5 or IKONOS-2, can offer the following advantages:
Synoptic coverage of
small or large geographic areas
Land cover maps generated
at considerably less cost
A digital format compatible
with Geographic Information Systems
Satellite-based Approach to Impervious Surface Mapping >>