LiDAR

LiDAR measures distance and maps surfaces by timing laser light reflected from objects. It can produce precise three-dimensional measurements across landscapes, structures, and moving scenes.

Time-of-flight: A measurement method that calculates distance from the time a signal takes to travel to a target and return. LiDAR estimates range by timing each laser pulse’s round trip.
Airborne laser scanning: The collection of laser measurements from an aircraft to map terrain and surface features. Aircraft-mounted LiDAR rapidly maps large areas from above.
Laser: A device that produces a narrow beam of coherent light through stimulated emission. LiDAR uses laser light as its measurement signal.
Radar: A sensing method that uses reflected radio waves to detect objects and measure their range or motion. Radar also measures by signal return, but uses radio waves rather than laser light.
Digital terrain model: A digital representation of bare-ground elevations, excluding buildings and vegetation. Filtering LiDAR returns can reveal ground beneath vegetation and create terrain models.
Laser rangefinder: An instrument that measures distance using a laser beam and its reflection from a target. It shares LiDAR’s pulse-ranging principle, typically measuring fewer directions.
Bathymetric LiDAR: LiDAR that uses laser light to measure underwater depths in shallow coastal waters. Specialized green-light systems map submerged terrain as well as shorelines.
Light detection and ranging: A remote-sensing method that uses light to measure distance and other properties of targets. LiDAR is the laser-based form of this broader measurement approach.
Sonar: A sensing method that uses sound waves to detect objects or measure distances, especially underwater. Sonar uses sound where LiDAR’s optical pulses cannot travel through water effectively.
Canopy height model: A spatial representation of vegetation height above the ground surface. LiDAR’s separate canopy and ground measurements make canopy-height mapping possible.

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