LiDAR, which stands for Light Detection and Ranging, is a remote sensing method that uses light in the form of a pulsed laser to measure ranges to the Earth. It is a distance technology that sends light to the ground and measures the time it takes for the reflected light to return.
In a LiDAR system, light is emitted from a rapidly firing laser, and it travels to the ground and reflects off of things like buildings and tree branches. The reflected light energy then returns to the LiDAR sensor where it is recorded. A LiDAR system measures the time it takes for emitted light to travel to the ground and back, and that time is used to calculate distance traveled. Distance traveled is then converted to elevation.
LiDAR systems allow scientists and mapping professionals to examine both natural and manmade environments with accuracy, precision, and flexibility. They are used to make digital 3-D representations of areas on the Earth's surface and ocean bottom of the intertidal and near coastal zone by varying the wavelength of light.
LiDAR is used in a wide range of land management and planning efforts, including hazard assessment, forestry, agriculture, geologic mapping, and watershed and river surveys
. It can also be used in any situation where the structure and shape of Earth's surface needs to be known, and can even measure some gases and particles in the atmosphere.
Some key features of LiDAR include:
Components: A LiDAR instrument principally consists of a laser, a scanner, and a specialized GPS receiver.
Types: Two types of LiDAR are topographic and bathymetric. Topographic LiDAR typically uses a near-infrared laser to map the land, while bathymetric LiDAR uses water-penetrating green light to also measure seafloor and riverbed elevations.
Applications: LiDAR is used in surveying, geodesy, geomatics, archaeology, geography, geology, geomorphology, seismology, forestry, atmospheric physics, laser guidance, airborne laser swathe mapping (ALSM), and laser altimetry. It is also used to make digital elevation models for use in geographic information systems, to assist in emergency response operations, and in many other applications.