Lidar (Light Detection And Ranging) Remote Sensing

Lidar (Light Detection And Ranging) is a remote sensing method used to examine the surface of the Earth. It is uses eye-safe laser beams to see the world in 3D, providing machines and computers an accurate representation of the surveyed environment.

Lidar is an optical means of measuring reflected light from distant objects to determine range, and to determine position. The Lidar uses 1.064 nanometer wavelength laser light pulses to measure distances by recording the time delay from the transmitted pulse and light reflected back from objects.

Lidar Sensor Types

Lidar systems can be divided into 2 major types: i)Airborne ii)Terrestrial

• Airborne Lidar Systems focuses on the processing and management of airborne Lider data in such Geospatial applications. This is mounted in an aircraft, scanning in one direction perpendicular to the flight of the aircraft in a push broom fashion. The data can be thought of as a long strip representing the surface of the underlying terrain. The application of this data is more oriented toward direct measurement of the earth’s surface used in conjunction with GIS, Remote Sensing or Photogrammetric applications, such as land cover mapping, hydrology analysis, site selection, etc. There are two types of airborne sensors: Topographic and Bathymetric.

• Terrestrial Lidar Systems are operated at ground level scanning in a vertical direction while rotating about a vertical axis. There are two main types of terrestrial lidar: Mobile and Static.

Application/ Uses of Radar Data

Lidar is commonly used to make high-resolution maps, with applications in;

• GIS
• Geography
• Geomorphology
• Geology
• Geodesy
• Geomatics
• Archaeology
• Surveying
• Seismology
• Forestry
• Atmospheric physics
• Laser guidance
• Laser altimetry
• Autonomous cars
• Helicopter Ingenuity

Advantages of using Lidar in GIS

• Lidar uses an active illumination sensor and can be collected day or night when compared to traditional photogrammetric techniques.
• Data can be collected quickly with very high accuracy.
• Surface data has a higher sample density. The high sample density improves results for certain applications such as floodplain delineation.
• Collect elevation data in a dense forest, where photogrammetry fails to reveal the accurate terrain surface due to dense canopy cover.
• Lidar does not have any geometric distortions like a side-looking radar.
• Lidar can be integrated with other data sources.

Using Lidar in ArcGIS

ArcGIS supports lidar data provided as LAS or ASCII files. There are 3 different formats datasets that can be used to manage and work with your lidar data in ArcGIS. The datasets are LAS dataset, Terrain dataset, and Mosaic dataset.

ArcGIS datasets that uses for Lidar data