LiDAR( also called Lidar, LIDAR, and LADAR) is a method for measuring distances（ranging）by illuminating the target with fiber laser light and measuring the reflection with a sensor. Differences in laser return times and wavelengths can then be used to make digital 3-D representations of the target. It has terrestrial, airborne, and mobile applications.
The term LiDAR was originally a portmanteau of light and radar.It is now also used as an acronym of light detection and ranging and laser imaging, detection and ranging Lidar sometimes is called 3-D laser scanning, a special combination of a 3-D scanning and laser scanning
LiDAR is commonly used to make high-resolution maps, with applications in surveying, geodesy, geomatics, archaeology, geography, geology, geomorphology,seismology,forestry, atmospheric physics,laser guidance, airborne laser swath mapping(ALSM), and laser altimetry. The technology is also used in control and navigation for some autonomous cars