LIDAR (Light Detection and Ranging) is a remote sensing technology that collects 3-dimensional point clouds of the Earth’s surface. This technology is being used for a wide range of applications including high-resolution topographic mapping and 3-dimensional surface modeling as well as infrastructure and biomass studies. Airborne LIDAR instrumentation uses a laser scanner with up to 400,000 pulses of light per second. The laser transmits pulses and records the time delay between a light pulse transmission and reception to calculate elevation values. These values are integrated with information from the aircraft’s Global Positioning System (GPS) and orientation (pitch, roll, and yaw) data from inertial measurement technology to produce point cloud data. Each data point is recorded with precise horizontal position, vertical elevation, and other attribute values.

Point cloud data represent the elevation of landscape features including crops, forests, roads, railways, airports, bare earth, mountains, valleys, lakes, rivers, glaciers, buildings, and other urban development. Topographic LIDAR instruments use wavelengths in the near-infrared regions of the spectrum with a Nominal Pulse Spacing (NPS) of 3 meters or finer. Since LIDAR can be reflected from any object the laser pulse strikes, up to five returns are collected per pulse. The multiple returns are recorded and each point is assigned a classification to identify landscape features. The intensity of the reflected energy is also captured and can be analyzed to provide additional information on terrain characteristics.