RAS question
Which of the following statements about LiDAR technology is correct? 1. LiDAR stands for Light Detection and Ranging. 2. It uses laser light to measure distances. 3. It cannot be used for creating 3D maps.
Correct answer: (A) 1 and 2 only.
LiDAR stands for Light Detection and Ranging and uses laser light to measure distances, while it can generate precise three-dimensional information rather than being unable to create 3D maps.
Explanation
Statements 1 and 2 are correct because LiDAR means Light Detection and Ranging, and NOAA describes it as a remote-sensing method that uses light in the form of pulsed laser to measure ranges, or variable distances. Statement 3 is incorrect: these light pulses, combined with other data recorded by the airborne system, generate precise three-dimensional information about the shape of the Earth and its surface characteristics. So the technology is not merely a distance-measuring tool; its distance measurements are the basis for detailed 3D mapping and terrain modelling. Therefore, only statements 1 and 2 are correct.
Why the other options are wrong
- (B) Option B wrongly includes statement 3, although LiDAR-generated pulses and related airborne data can produce precise three-dimensional information.
- (C) Option C treats all three statements as correct, but statement 3 contradicts LiDAR's established use in creating 3D maps and terrain models.
- (D) Option D includes statement 3 and excludes statement 2, even though LiDAR uses laser light to measure distances and can support 3D mapping.
Concept
This tests the Science and Technology syllabus idea of remote-sensing tools and their applications. It recurs in RAS because mapping, terrain modelling and geospatial technologies are common links between science, geography and governance questions.