Remote Sensing

Acquisition of information about a certain phenomenon or an object without making any physical contact with it is called remote sensing. It generally refers to the use of aerial sensor technologies that do detect and also classify objects in the atmosphere, earth surface and also in the oceans through some propagated signals, for example satellites or electromagnetic radiation that is emitted from an aircraft.

Passive Remote Sensing

When passive sensors are used to detect natural radiation that is reflected or emitted by an object or the surrounding area is called passive remote sensing. Sunlight that is reflected by objects or surrounding areas is the most common source of radiation that is measured by the passive sensors. Infrared, photography, charge-coupled devices and radiometers are examples of passive remote sensors.

Active Remote Sensing

Active remote sensing is where some energy is emitted in order to scan objects and areas. The sensor then detects and also measures the radiation that is back-scattered or reflected from the target.

The LiDAR and the RADAR are examples of active remote sensing where the time delay between emission and the return is measured, the location, height, speed and the direction of the object are also established.

Advantages of Remote Sensing

One of the advantages of remote sensing is that it’s possible to collect data in dangerous and inaccessible areas.
There are various applications of remote sensing that includes monitoring deforestation in areas like the Amazon Basin, depth sounding of coastal  and ocean depths, and glacial features in Antarctic and the Arctic regions.

The military use remote sensing in times of war to collect data in dangerous areas. It also replaces slow and costly data collection on the ground and it ensures that objects or areas are not disturbed in the process. Data collected is used to analyze and compare things like pollution, forestry, erosion, land use and weather among other uses.