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If you know where to look in New Mexico’s vast Chihuahuan Desert, you can find cows making sharp turns, as though they had run into a barbed-wire fence, even though there is no barrier to be seen. Watching cows turn might sound even sillier than the rural prank of cow-tipping, but what’s going on is worth tracking. The cows are part of a potentially lucrative experiment in using the Global Positioning System and show that when it comes to novel applications for the GPS, well, the sky may be the limit. "The number and variety of applications seem to just keep increasing," says Professor Richard Langley, an expert on GPS at the University of New Brunswick in Canada. The cows wear collars that communicate with the two dozen GPS satellites that were initially deployed to help the military aim nuclear missiles and that have entered commercial use. Dean Anderson, the U.S. Department of Agriculture researcher responsible for developing the collars, says that if a cow strays outside a designated area, a microprocessor in the collar whispers the electronic equivalent of a cowboy’s traditional "gee" [go right] or "haw" [go left] toward the animal’s correct ear. Anderson says cows and most other animals naturally move in the opposite direction of a sharp sound. "Animals are pretty darn smart," Anderson says. The sound cues grow in intensity if the animal ignores them. If the cow crosses a specified boundary, the collar applies a mild shock. The "roundup" collar could save ranchers thousands of dollars a mile in fencing, and cattlemen could avoid overgrazing by using the GPS collars to move livestock. Anderson hopes the collar eventually will be manufactured for widespread commercial use. At ski resorts, the GPS is being used to conserve energy and water. Radar scanners linked to the GPS are dragged across ski slopes, to produce three-dimensional color maps that show snow-pack depth to within a couple of inches. By knowing the precise depth and distribution of snow, the ski resort can turn off snow guns to avoid unnecessary snowmaking. "There’s always a tendency to over-make snow [because] you don’t want unhappy customers," says Scott Fifer, president of Resource Engineering Inc., the water resources engineering firm that developed the SnowQUEST system. The system has been deployed by resorts at Vermont’s Stratton Mountain and Colorado’s Aspen and Copper mountains. In Flathead County, Mont., GPS is being used to re-create crime scenes on three-dimensional maps, making it easier for juries to visualize events such as getaways. That has helped jurors reach verdicts, says Rick Breckenridge, a mapping expert for the county. At a crime scene, he uses a GPS receiver and survey equipment to pinpoint locations. He then plots the information on a map, to show where evidence was found and to bring into focus the role of roads, ditches, buildings, and other geographic features. In one case, a map was used to show how a witness standing on a balcony at night could have heard an argument 150 feet away that preceded a shooting. Between Denver and Durango, Colo., mapping consultant Jerry Brown and a group of friends transported a GPS receiver along a popular, 487-mile trail to produce an ultra-accurate, CD-ROM map. The digital map upgrades government-issued topographical maps that are as much as two miles off base because the trail has been rerouted in so many places. Hikers using a GPS receiver and the new map will be much less likely to get lost among the trail’s many intersections. In Germany, researchers at the University of Frankfurt’s Zoology Institute have developed a GPS-based tracking system to track pigeons moment by moment and try to solve the mystery of how they find their way home. The birds are harnessed with lightweight-tracking devices that can store a position each second of the birds’ flight. It’s no accident that early uses of the GPS are happening in Montana, Colorado, Germany, and other places with wide-open spaces. GPS signals can be blocked or distorted in urban areas. In addition, most GPS receivers are accurate to just 25 meters. (Much more expensive professional receivers are accurate to one meter.) Accuracy to 25 meters lends itself fine to cows grazing but doesn’t work so well if companies try to use the system to pinpoint locations in an office building. Besides, the GPS takes a two-dimensional view of the world—a worker searching for the nearest printer in an office building might be steered to one that, from the sky, seems to be just 40 feet away but is really 40 feet away horizontally and four floors away vertically. Still, the GPS is finding uses in cities, too. Motorists in Florida are using it to locate Walt Disney World and other tourist sites. TelEvoke Inc. has developed a system that will alert a car owner if his vehicle leaves a certain geographical area—in other words, if it is stolen. Using a similar system, the owner of a fleet of small trucks knew a driver who complained of traffic delays had actually stopped for an hour at a strip joint. Having warned drivers Big Brother was watching them via the GPS, the owner summarily fired the driver. "There is no limit to what we can do," says Professor Gerard Lachapelle, an expert in wireless location at the University of Calgary. "Big changes are about to hit us."
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