Remote sensing is the scientific method of detecting and monitoring the physical properties of an area by calculating its emitted and reflected radiation at a distance (generally from an aircraft or satellite). It is the accumulation of information about a phenomenon or objects without having physical contact with the targeted objects. It is especially applied to gather details about the Earth and other solar planets. Remote sensing is employed in various fields, including ecology, hydrology, geology, meteorology, geography, oceanography, glaciology, etc. It has also been applied in intelligence, economic, planning, and military fields.
The present-day form of remote sensing evolved with the development of aerial flight. One of the earliest proponents of aerial photography was balloonist G. Tournachon. He produced images while flying in his balloon. Kits, unmanned balloons, and rockets were used for making remote images in the early stages.
Active remote sensing uses a man-made source of radiation as the inspecting medium. The resulting signal disperses back to the sensor and characterises the Earth or the atmosphere. LiDAR and RADAR are the two main examples of active remote sensing. Both emit radiation beams from a sensor and calculate the scattered radiation that has returned to the sensor.
Passive remote sensing depends on solar radiation as the source of illumination. Hyperspectral and multispectral sensors are the main ones that use this type of remote sensing. It generally focuses on shortwave infrared, visible, and near-infrared spectral regions. Numerous man-made satellites with onboard passive sensors are used for various purposes.
Important Uses of Remote Sensing
Special optical cameras or sensors accumulate remotely sensed images that enable scientists to sense the properties and functioning of the Earth or any other targets.
Image sensors on aircrafts and satellites take images of huge areas on the Earth’s surface. It allows researchers to observe optically much more than we can watch while standing on the ground. Sonar systems on water vehicles can be employed to produce ocean floor images without travelling to the ocean floor. It allows researchers to observe optically much more than we can watch while standing on the ground. Camera sensors on satellites are used to generate images of temperature variations in the oceans. A few other use case scenarios of remotely sensed images are:
- Tracking and analysis of clouds can be done through remote sensing. It allows meteorologists to predict and observe weather patterns, volcanic eruptions, sea movements, etc.
- Massive forest fires can be mapped and tracked from space. It allows us to observe a much larger area than from the ground.
- Remotely sensed images help to track down the development of a city. Long term changes in forests and farmlands can be easily tracked down using this technology.
- Detecting and mapping ocean floor topography: hidden underwater deep canyons, mountain ranges and magnetic activities can be easily detected and analysed using remotely sensed images.
Important Remote Sensing Questions with Answers
1) What is meant by remote sensing?
Remote sensing is the scientific method of detecting and monitoring the physical properties of an area by calculating its emitted and reflected radiation at a distance (generally from an aircraft or satellite). It is the accumulation of information about a phenomenon or objects without having physical contact with the targeted objects. It is especially applied to gather details about the Earth and other solar planets.
2) What are the science fields that depend on remote sensing?
Remote sensing is applied to gather details about the Earth and other solar planets. Remote sensing is employed in various fields, including ecology, hydrology, geology, meteorology, geography, oceanography, glaciology, etc. It has also been applied in intelligence, economic, planning, and military fields.
3) How did remote sensing start?
The present-day form of remote sensing evolved with the development of aerial flight. One of the earliest proponents of aerial photography was balloonist G. Tournachon. He produced images while flying in his balloon. Kits, unmanned balloons, and rockets were used for making remote images in the early stages.
4) _____ refers to the use of aircraft or satellite-powered sensor technologies to identify and classify bodies on the Earth.
Answer: Remote sensing
Explanation: Remote sensing refers to the use of aircraft or satellite-powered sensor technologies to identify and classify bodies on the Earth.
5) _____ radiation is generally used in remote sensing technology.
Answer: Electromagnetic
Explanation: Electromagnetic radiation is used in remote sensing technology.
6) What are the two types of remote image sensing technology?
The whole technology can be split into active remote sensing and passive remote sensing. They are mainly differentiated by the type of medium they are using to acquire the targeted information.
7) What is meant by active remote sensing?
Active remote sensing uses a man-made source of radiation as the inspecting medium. The resulting signal disperses back to the sensor and characterises the Earth or the atmosphere. LiDAR and RADAR are the two main examples of active remote sensing. Both emit radiation beams from a sensor and calculate the scattered radiation that has returned to the sensor.
8) What is meant by passive remote sensing?
Passive remote sensing depends on solar radiation as the source of illumination. Hyperspectral and multispectral sensors are the main ones that use this type of remote sensing. It generally focuses on shortwave infrared, visible, and near-infrared spectral regions.
9) What are the important uses of remote sensing?
Special optical cameras or sensors accumulate remotely sensed images that enable scientists to sense the properties and functioning of the Earth or any other targets.
Image sensors on aircrafts and satellites take images of huge areas on the Earth’s surface. It allows researchers to observe optically much more than we can watch while standing on the ground. Sonar systems on water vehicles can be employed to produce ocean floor images without travelling to the ocean floor. It allows researchers to observe optically much more than we can watch while standing on the ground. Camera sensors on satellites are used to generate images of temperature variations in the oceans.
10) What are the specific uses of remote image sensing in the case of weather?
Tracking and analysis of clouds can be done through remote sensing. It allows meteorologists to predict and observe weather patterns, volcanic eruptions, sea movements, etc.
11) What are the uses of remote image sensing in the study of oceans?
Remote sensing is extensively used in detecting and mapping ocean floor topography. Hidden underwater deep canyons, mountain ranges and magnetic activities can be easily detected and analysed using remotely sensed images.
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Practices Questions
1) What is meant by RADAR?
2) What is the difference between active remote sensing and passive remote sensing?
3) What is meant by LiDAR?
4) What is a sonar system?
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