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Project Description-
• NCALM provides research-grade
Airborne Laser Swath Mapping (ALSM)
data to National Science Foundation-supported
researchers. The ALSM data can be used to produce highly accurate, three-dimensional, digital topographical maps of a large area of land surface. The major component of the system is a laser that emits tens of thousands of short pulses of light per second. The laser is mounted in a small, twin-engine aircraft, and the laser pulses are directed towards the ground by a scanning mirror. Each pulse illuminates an area, or footprint, of about 15 centimeters in diameter and the light is scattered back to a sensor in the aircraft. The round-trip travel time of the laser light allows researchers to compute the three-dimensional locations of the points on the ground relative to the aircraft. An extremely precise GPS unit and an Inertial Measurement Unit (IMU) keep track of the location of the aircraft on the planet. The resulting set of latitudes, longitudes, and heights of millions to billions of points is then transformed into highly accurate maps. This requires filtering the points to remove vegetation, buildings, and other non-earth objects. While the scanning equipment is incredibly accurate, filtering is still in its infancy and is the focus of considerable research.
• The power of laser mapping lies in quantifying what is immediately visible and in revealing the landforms that lie below natural and man-made obstructions with a height accuracy of less than 10 cm. For example, for a forested area, researchers can generate both a high-resolution canopy and a bare-earth digital elevation model. Among a long list of potential applications, the ALSM data is valuable in understanding geological and geomorphological processes, such as faulting and channelization.
Participating Institutions-
Department of Civil and Coastal Engineering,
College of Engineering, University of Florida (UF)
Department of Earth and Planetary Science,
University of California, Berkeley (UCB)
Online Information-
NCALM
NCALM at Berkeley
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