What is LiDAR
Many people have heard the term “LiDAR” but few actually know what it is. 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 variable distances to the Earth. These light pulses, combined with other data recorded by the airborne system, generate precise, 3D information about the shape of the Earth and its surface characteristics. A LiDAR instrument typically consists of three parts: the laser, a scanner, as well as a specialized GPS receiver. Positioned under aircraft, it can to acquire data over wide-areas of interest for mapping purposes.
When an airborne LiDAR system is pointed at a specific area on the ground, the beam of light is shot from the aircraft at the surface where it will then be reflected back to the sensor to measure the range. You then can combine the laser ranges with position and orientation data generated from the GPS receiver system, scan angles as well as the calibration data. The result is a called a “point cloud”, which is a dense group of elevation points.
Every point in the point cloud has 3D coordinates (latitude, longitude, and height). These point are from the Earth’s surface, reflecting the laser pulse. Many different geospatial products such as elevation models and building models can be created using Point Clouds. These systems allow scientists and other geographic specialists to examine both natural and manmade environmental changes with top level accuracy. NOAA scientists are using this method to help examine shoreline maps. They also use it to assist in emergency response operations like flood disasters and forest fires.
Types of LiDAR
There are two types of LiDAR, airborne and terrestrial. Terrestrial LiDAR systems, which are used to map highways and roads, are installed to moving vehicles. The greatest use for terrestrial LiDAR today is to work towards self-driving cars as well as the advancements into Smart Cities. Airborne LiDAR is split into two categories, Topographic, and Bathymetric. Topographic LiDAR typically uses a near-infrared laser to map the land, while bathymetric uses water-penetrating green light to also measure seafloor and riverbed elevations.
The advancements in LiDAR impact the industry by making it more accessible. This surveying method collects data quickly and efficiently, making it a widely used form of surveying. Spatial models created using this method have a low error margin. They also save a considerable amount of money and help improve the final decision making. It can help track deforestation patterns more efficiently, making it essential for tracking climate change.
At Leading Edge Geomatics, we use LiDAR to help our clients with many specific mapping needs. On any given day we can send out our fleet of aircrafts out across North America to collect data. Whether it be for flood mapping, forestry or vegetation management, topographic mapping, or bathymetric LiDAR, we always find the right mapping solutions.