LiDAR
Also called: Light Detection and Ranging · Topic: Remote Sensing, GIS and GNSS · NCERT: Beyond NCERT
Meaning
LiDAR (Light Detection and Ranging) is an active sensor. This means it sends out its own energy instead of relying on sunlight. It fires laser pulses from aircraft, drones or satellites and times how long each pulse takes to bounce back. The time gives the distance, so LiDAR can map heights in fine detail. Some pulses slip through gaps in leaves, so it can map the ground even under forest cover. It is used to make digital elevation models (DEMs, height maps of the land) and 3-D city models.
Example
India's National Geospatial Policy 2022 aims for digital twins of major cities by 2035. Digital twins are detailed 3-D digital copies of a city. Height data from LiDAR is a key input for building such 3-D models of buildings and streets.
Don't confuse with
- Radar: this is also active, but it uses microwave pulses that pass through cloud. LiDAR uses laser light, which gives sharper height detail but cannot see through thick cloud.
Related concepts
- Sensor
- Photographic sensor
- Multispectral scanner
- Swath
- Whiskbroom scanner
- Instantaneous field of view
- Pushbroom scanner
- Passive and active remote sensing
- Radar
- Synthetic aperture radar