LiDAR (Light Detection and Ranging) was developed in the late 1980s to map hazardous and inaccessible terrain, and it has revolutionised studies in coastal locations. It is a method of remote sensing that scans the Earth’s surface using lasers to measure ranges (distances). Data are collected from manned aircraft or, more commonly today, from drones. A laser is fired from the aircraft at a target area, and this is then reflected by the surface(s) it encounters (Figure 1). A sensor records this reflected light, and distance to the ground is calculated from the time taken for the light to reflect and the speed of the laser pulse.
When the laser ranges are combined with GPS position and orientation, a data-rich group of elevation points is created, called a point cloud. Each point in the cloud has 3D coordinates (latitude, longitude and height) corresponding to a specific point on the surface. Point clouds can therefore be used to produce digital elevation models (DEMs), building 3D models of the ground surface and contour maps with very fine resolutions, sometimes as low as a few centimetres (Figure 2).
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