TAG: GS-3: SCIENCE AND TECHNOLOGY
CONTEXT: Scientists recently used LiDAR technology to discover an ancient Mayan city hidden for centuries beneath the dense jungle of Mexico.
EXPLANATION:
About LiDAR?
- LiDAR (Light Detection and Ranging) is a remote sensing technology that uses laser light pulses to measure distances between a sensor (often airborne) and Earth’s surface.
- It produces high-resolution, 3D models of ground elevation with up to 10 cm vertical accuracy, as per the US Geological Survey.
Applications of LiDAR
- Geography and Mapping: Creates precise 3D information for topographic mapping.
- Urban Planning and Infrastructure: Used in planning transportation routes, assessing flood risk, and managing natural resources.
- Conservation: Helps monitor forest health, manage habitats, and detect environmental changes.
- Engineering and Policy: Provides data for infrastructure design, environmental policy making, and land-use planning.
How Does LiDAR Work?
- LiDAR Setup: Includes a laser, a scanner, and a GPS receiver. The laser emits rapid pulses of light that reflect off surfaces on the ground, including natural features and man-made structures.
- Data Collection: The reflected light returns to the sensor, and the LiDAR system calculates the two-way travel time to determine the distance to each point on Earth’s surface.
- Data Processing: GPS and Inertial Measurement System (IMS) data are used to create accurate maps. The initial data forms a “point cloud” representing surfaces like vegetation, buildings, and terrain.
- “Bare Earth” Model: By filtering out structures and vegetation, LiDAR can create a Digital Elevation Model that shows just the ground terrain.
Why is LiDAR Useful for Archaeologists?
- Large-Area Surveying: LiDAR enables archaeologists to study extensive areas quickly, bypassing the need for labour-intensive, on-ground exploration.
- Detailed Site Mapping: With “bare earth” models, archaeologists can strip away vegetation layers to reveal hidden archaeological sites.
Where is the Indian Government using Lidar?
- Forest Mapping: The Ministry of Environment is piloting LiDAR-based Forest mapping across states to improve forest management and accurately monitor forest cover changes.
- Water Resource Management: WAPCOS is using LiDAR to identify groundwater recharge zones, aiding water resource management and mitigating human-animal conflicts in forested areas.
- Urban Planning: Chandigarh and Gujarat are using LiDAR for GIS mapping and drone-based surveys, respectively, supporting detailed city models, urban planning, and infrastructure mapping.
- High-Speed Rail Projects: NHSRCL (National High-Speed Rail Corporation Limited) uses aerial LiDAR surveys for the Delhi-Varanasi High-Speed Rail Corridor, reducing survey time from 10-12 months to 3-4 months by capturing detailed topographical data within a 300-meter corridor.
- National Highways: NHAI mandates Mobile LiDAR for feasibility studies and project reports, enhancing the accuracy and efficiency of highway surveys across extensive networks.
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