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Article: The forecast doesn't always call for clear skies. (GPS/GIS Integration).(using line of sight for collecting GIS data)(Column)
- Article from:
- GEO World
- Article date:
- September 1, 2002
- Author:
CopyrightCOPYRIGHT 2002 Bev-AL Communications, Inc. This material is published under license from the publisher through the Gale Group, Farmington Hills, Michigan. All inquiries regarding rights should be directed to the Gale Group. (Hide copyright information)
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In previous "GPS/GIS Integration" columns, I discussed several GIS data collection methods, with an obvious concentration on Global Positioning System (GPS) technology (see "Walking the Blurred Line of Geodesy," Geo World, June 2002, page 28). But even with the wide variety of data capture tools available, GIS data collection has become an unwitting slave to a "clear sky."
Of the most popular data capture methods, clear sky seems a prime ingredient, as photogrammetry, remote sensing, and light detection and ranging (LIDAR) need a "line of sight" to target objects. Even on-the-spot terrestrial capture via GPS requires four visible satellites for 3-D positioning. ...