LiDAR (Light Detection and Ranging)
Definition
An active remote sensing technique that emits laser pulses and measures the time of return to calculate distance to reflecting surfaces. Airborne systems sweep a laser across the terrain to build a three-dimensional point cloud.
- Full name
- Light Detection and Ranging
- Method
- Laser pulse time-of-flight distance measurement
- Platform
- Airborne systems sweep terrain
- Output
- Three-dimensional point cloud
Common questions
How does airborne LiDAR reveal ground features hidden under vegetation?+
Some laser pulses penetrate gaps in vegetation canopy and reflect off the ground beneath, and by filtering the point cloud to keep only these ground returns, analysts can reconstruct a bare-earth terrain model even in forested terrain.
Why is LiDAR particularly suited to detecting ground disturbance such as a clandestine grave?+
Because it captures dense, precise elevation data over wide areas, subtle surface anomalies like mounding, settling, or unnatural micro-topography that are hard to see on foot or in photographs can become visible when the point cloud is processed and visualised.
Related terms
- Bare-Earth DTM
- A digital terrain model produced by filtering LiDAR returns to ground-level pulses only, removing vegetation and structure returns. The resulting surface represents...
- Curvature
- A DTM derivative measuring the rate of change of slope. Profile curvature (along the slope direction) identifies convex mounds and concave hollows....
- Hillshade
- A raster derived from a DTM by simulating illumination from a defined sun position (azimuth and altitude angle). Produces light-and-shadow contrasts that...
- Point Density
- The number of LiDAR returns per unit area of ground surface, typically expressed as points per square metre. Higher density enables finer...
- Terrestrial Laser Scanning (TLS)
- A ground-based 3D LIDAR survey instrument that captures millions of range measurements per scan to produce a millimetre-accurate point cloud of the...