Talking about Remote Sensing what is the first thing comes that to your mind? I think you will come up with answers like satellites, drones, and maps. Do you know the fact that we are also doing remote sensing all the time? yes, we do. With our eyes, with our nose, with our ears. we do remote sensing every time. Let’s see what is this Remote Sensing, then you will get the idea.
Remote Sensing is sensing a distant object without getting in physical contact with it. Here is the definition-
“Remote sensing is the science of acquiring information about the Earth’s surface without actually being in contact with it. This is done by sensing and recording reflected or emitted energy and processing, analyzing, and applying that information.”
With this definition, we can understand how remote sensing work. In the process, we are intricating with incident radiation and the object we want to sense. This can be utilized by using Imaging System. It also involves sensing emitted energy and the use of non-imaging sensors.
So, now we know what is remote sensing, let’s see, how it works.
When we look from our eyes what we see is not an object but the light reflected from that object. We need any energy source or illuminate the object/target. And this light comes from Sun or any artificial energy source (Flashlight). The energy coming from Sun is called EMR (Electromagnetic Radiation). We need any energy source or illuminate the object/target.
What is EMR (Electromagnetic Radiation)
Electromagnetic radiation consists of an electrical field(E) which varies in magnitude in a direction perpendicular to the direction in which the radiation is traveling, and a magnetic field (M) oriented at right angles to the electrical field. Both these fields travel at the speed of light (c).
In simple words, EMR is incident energy that contains an electric and magnetic field traveling in the same direction at the same speed. Two characteristics of electromagnetic radiation are particularly important for understanding remote sensing. These are the wavelength and frequency.
- Wavelength is measured in metres (m) or some factor of metres such as nanometres (nm, 10-9 metres), micrometres (μm, 10-6 metres) (μm, 10-6 metres) or centimetres (cm, 10-2 metres).
- Frequency refers to the number of cycles of a wave passing a fixed point per unit of time. Frequency is normally measured in hertz (Hz), equivalent to one cycle per second, and various multiples of hertz.
Wavelength and Frequency are inversely related to each other. The shorter the wavelength, the higher the frequency. The longer the wavelength, the lower the frequency.
Scope of Remote Sensing
Remote sensing is a technology that allows scientists and researchers to observe and collect data on various phenomena on the Earth’s surface and atmosphere. This technology is used in a wide range of fields, including meteorology, oceanography, geology, and environmental science.
One of the key concepts in remote sensing is the scope of the data that is being collected. This refers to the spatial, temporal, and spectral range of the data that is being gathered by the remote sensing system.
Spatial scope refers to the area of the Earth’s surface that is being observed by the remote sensing system. This can range from a small area, such as a single building or field, to a large region, such as an entire continent or even the entire globe.
Temporal scope refers to the time period over which the data is being collected. This can range from a single moment in time, such as a snapshot taken by a satellite, to a longer period, such as a week, month, or even year.
Spectral scope refers to the range of wavelengths of the electromagnetic spectrum that are being detected by the remote sensing system. This can include visible light, near-infrared, and even radar and other forms of electromagnetic radiation.
The scope of a remote sensing system is an important consideration, as it determines the types of phenomena that can be observed and studied. A system with a wide scope can provide a more comprehensive view of a given area, while a system with a more limited scope may be better suited for studying specific phenomena in more detail.
In conclusion, the scope of a remote sensing system refers to the spatial, temporal, and spectral range of the data that is being collected. This concept is an important consideration in the use of remote sensing technology, as it determines the types of phenomena that can be studied and the level of detail that can be observed.
Advantages of Remote Sensing
There are several advantages to using remote sensing technology in a variety of fields, including the following:
- It allows for the collection of data on a large scale, over a wide area, without the need for direct physical access to the area being studied. This makes it an efficient and cost-effective way to gather information.
- Remote sensing systems can collect data in real-time, providing researchers with up-to-date information on the phenomena they are studying.
- Remote sensing technology can detect a wide range of phenomena, including changes in land cover, vegetation health, and even atmospheric conditions. This allows researchers to study a wide range of phenomena and to understand their relationships and interactions.
- Remote sensing data can be easily shared and accessed by other researchers, allowing for collaboration and the development of a more comprehensive understanding of the phenomena being studied.
- In some cases, remote sensing technology can provide information that is not possible to collect through other means, such as data on the Earth’s surface from space. This allows researchers to study phenomena in unique and previously inaccessible ways.
Overall, the advantages of remote sensing technology make it a valuable tool for researchers in a wide range of fields, allowing for the efficient and effective collection of data on a large scale.
Disadvantages of Remote Sensing
While there are many advantages to using remote sensing technology, there are also some disadvantages to consider. These include the following:
- The cost of acquiring and operating remote sensing systems can be prohibitively expensive for some organizations or individuals.
- The resolution of the data collected by remote sensing systems is often limited, making it difficult to study small-scale phenomena in detail.
- The accuracy of remote sensing data can be affected by a variety of factors, such as the quality of the sensors, the presence of clouds or other obstructions, and the angle of the satellite or other platform from which the data is being collected.
- Remote sensing data is often collected from a distance, which can make it difficult to accurately interpret or verify the information that is being collected.
- In some cases, the use of remote sensing technology may be restricted by legal or regulatory limitations, such as privacy concerns or restrictions on the use of certain wavelengths of the electromagnetic spectrum.
Overall, while remote sensing technology offers many advantages, there are also some limitations and disadvantages to consider when using it to study phenomena on the Earth’s surface and atmosphere.
- Remote Sensing of the Environment (Second Edition) by John R. Jensen