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  February 5, 2001

High-Resolution Satellite Images
Boost Earth Science Research

It's a "local" picture, taken with a camera 423 miles away.

The picture is one of a collection of high-resolution images of Connecticut taken by the IKONOS commercial satellite and recently acquired by a team of UConn scientists and educators who use satellite images to measure and monitor changes on the Earth.

The data include 12 images of eastern Connecticut, totaling 3,000 square kilometers and covering a rectangular area from Windsor in the northwest to Waterford in the southeast. They were taken between April and July of last year.

Researchers in UConn's Laboratory for Earth Science Information Systems, the first organization in the state to acquire IKONOS images, are using the images to extract high-resolution land-cover and land-use data, to quantify forest fragmentation and urban sprawl, and to determine areas with impervious surfaces that do not allow water to infiltrate the soil and are indicators of non-point source pollution.

As a NASA Regional Earth Resource Applications Center since 1999 - one of just nine nationwide - UConn received the images through NASA under a federal government program that directs the space agency to buy remote sensing data from the private sector in order to make it available to the scientific community.

The data rival the quality of photos taken by U.S. spy satellites. The lab's director, Daniel Civco, an associate professor of natural resources management and engineering, says he is amazed by their unprecedented level of accuracy and detail. "We've entered into a new revolution with respect to satellite remote sensing, obtaining images rivaling photographs acquired from aircraft," he says.

What makes IKONOS a milestone in the burgeoning billion-dollar, high-resolution imaging business, is its ability to capture - in black and white - objects on the ground as small as trees, cars and crowds, Civco explains, although it can not identify individual humans. Unlike the 10-meter images available from the French SPOT satellites or the 15-meter images available from Landsat 7, the images from IKONOS get analysts close enough to discern "the painted lines in the parking lot," he says.

IKONOS can also provide multispectral - color - images with a ground resolution of four meters, revealing information that cannot be seen with the naked eye, such as chlorophyll content of plants, chemical composition, and surface water penetration.

Until now, only military satellites have photographed earth in such detail. Yet the U.S. government, which approved IKONOS in 1994, expects that the orbiting eyes of high-resolution commercial satellites will begin to help a diverse set of clients - farmers, urban planners, zoning officials, utility companies, and others - do their work more efficiently.

Sandy Prisloe, a geographic information systems educator at the University's Cooperative Extension Center in Haddam and a co-director of the UConn Regional Earth Resource Applications Center, uses satellite data to develop computer models of impervious land surface within watersheds to show local zoning officials.

Prisloe says the IKONOS data "allow us to do things that were not possible in the past.

"Unlike coarse-resolution and medium-resolution satellite imagery that are unable to depict relatively small landscape features, the IKONOS imagery is able to clearly show individual trees and buildings," he says.

"The increased resolution of the imagery gives us the ability to quickly and accurately interpret urban landscape features - something that was not possible with previous types of satellite data - and to use this information to develop better land use plans."

Because of the discrepancy that exists between the resolution of data collected from the earlier generation of satellites and the IKONOS images, another UConn project seeks to integrate the data and develop land-use and land-cover classification techniques to expand the utility of the less sensitive imagery.

"At a minimum, this project will help us develop a suite of sophisticated data analyses using medium-resolution imagery," Civco says. "We've got all the pieces of the puzzle. Now we are going to find out how they all fit together."

David Bauman