Remote Sensing – Environment, Applications and Benefits

In contrast to in situ or on-site observation, remote sensing is the process of gathering information about a subject or phenomena that does not include having direct physical contact with the subject or event in question. The phrase is used in particular when referring to the process of gathering knowledge about Earth and other planets. The majority of disciplines that fall under the umbrella of Earth science also make use of remote sensing geography. Some of these subjects include geography and land surveying. It also has applications in military intelligence, commerce, the economy, planning, and humanitarian work, amongst other areas.

What is Remote Sensing?

In geospatial technology, remote sensing collects samples that are emitted through electromagnetic radiation and reflected from the Earth’s atmospheric, terrestrial, and aquatic ecosystems. This allows for the detection and monitoring of the physical characteristics of an area without the need to make direct physical contact with the area. 

The radiation that is reflected or released by an item or the area around it may be gathered using passive sensors, which are sensors that react to external stimuli. Reflected sunlight is the most prevalent kind of radiation source that is monitored using passive remote sensing techniques. Charge-coupled devices, radiometers, film photography, and infrared are a few well-known examples of popular types of remote sensing.

Remote Sensing of the Environment

The study of the environment carried out at a distance via satellite imaging, aerial photography, and radar is a remote sensing environment. By taking readings of electromagnetic waves, remote sensors can obtain information. Publishing research findings on the theory, science, applications, and technology of remote sensing of the environment provides a service to the community of people who work in remote sensing.

How do remote sensing satellites work?

Observation satellites of the Earth, often known as remote sensing satellites, are another name for remote sensing satellites. They may also be used for environmental monitoring, meteorology, and mapping, in addition to their role as spy satellites. The most prevalent kind is Earth-imaging satellites, which capture pictures from space quite similar to those taken from aeroplanes. Remote sensing of the environment is used by Some EO satellites that can do so without generating images, as with GNSS radio occultation.

What is Active Remote Sensing?

Active and passive remote sensing are the two primary categories of remote sensing, each categorised according to the source of signal used to investigate an object. Active remote sensing devices generate their source of emission or light to function, as opposed to passive instruments, which depend on the reflected one.

Active Remote Sensing Instruments

When doing remote sensing, each active sensor first sends its signal to the target item and then examines the response, also known as the received amount. Microwaves are used in the vast majority of devices because they are resistant to the effects of weather to a large extent. Different active remote sensing methods may be categorised according to what they broadcast (light or waves), as well as what they determine.

1. Radar

It refers to a sensor that helps range using radio frequencies. It is distinguished by the impulses that are emitted by the antenna. When the energy flow in radar active remote sensing comes into contact with an obstruction, part of that energy is scattered back to the sensor. It is possible to estimate the distance to the objective based on the total cost and the time it takes to arrive there.

2. Light 

It is used in the process of determining distance in the lidar. Transmitting light impulses and analysing the amount collected are both required steps in the Lidar active remote sensing process. When the amount of time is multiplied by the speed of light, the distance and position of the target may be calculated. A lidar-based laser altimeter is used to measure elevation. The distance between two points may be determined by ranging instruments using either one or two similar devices mounted on separate platforms that transmit signals to each other. Sounder investigates the vertical circumstances of the weather by sending out impulses if it belongs to the active category.

3. Scatterometer 

It is a specialized instrument that measures the radiation bounced back or backscattered.

Applications And Benefits

Aside from the many ways in which they may be implemented, active remote sensors essentially don’t have any constraints when it comes to the circumstances of the study. Active remote sensing systems are completely functional throughout the day since they do not need sunlight and are largely independent of air scatterings. Passive types of remote sensing systems only work when sunlight is present.

What is Passive Remote Sensing?

In contrast to their active counterparts, passive remote sensing sensors do not transfer any of their internal energy to the item or surface being studied. The reflected natural energy, such as sunlight, is the source of information for passive remote sensing. Because of this need, it can only be used when there is sufficient sunshine; otherwise, there will be no light to reflect.

In passive remote sensing, multispectral or hyperspectral sensors are used to get measurements of the target amount using various band configurations. The number of channels in each of these combinations makes them unique. The range of bands includes spectral ranges that are both visible and invisible to the human eye.

Remote Sensing Applications

1. Land Use Mapping

It is helpful to acquire an up-to-date land use pattern of broad regions at any moment using remote sensing geography data. This data may also be used to monitor changes that occur from time to time. Maps of roads, asphalt conditions, and the boundaries of wetlands may all be brought up to date with its help. Regional planners and administrators use this information when formulating policy measures to facilitate comprehensive growth across the area.

2. Weather Forecasting

The practice of weather forecasting in India makes substantial use of remote sensing technology. In addition, it is utilised to provide people warning of approaching cyclones.

3. Environmental Study

Deforestation, the deterioration of fertile lands, pollution in the atmosphere, desertification, eutrophication of huge water bodies, and oil spills from oil tankers are some of the environmental issues that may be investigated with its help.

 4. Study of Natural Hazards

The use of remote sensing allows for the investigation of damage brought on by natural disasters such as earthquakes, volcanoes, landslides, floods, and the melting of ice in polar areas. The use of remote sensing may often be used when attempting to forecast the advent of natural disasters.

5. Resource Exploration

The use of remote sensing data is important for detecting fossil fuel reserves, rapidly preparing lineament and tectonic maps, identifying areas for quarrying minerals, and updating existing geological maps. In addition, remote sensing data is useful for updating existing geological maps.

Applications Of Remote Sensing Geography

These kinds of data may be put to use in the process of formulating plans for usage both before and after natural catastrophes. The system is especially important for environmental monitoring and the management of natural resources. In addition, it analyses humans’ influence on the surrounding environment. Oceanography is another field that may benefit from remote sensing since it monitors ocean circulation, temperature, and wave heights to get a deeper understanding of ocean resources. The method has applications in geology, mineral exploration, agriculture, and forestry.

Limitations Of Remote Sensing

The resolution of the pictures obtained by satellites might often be too low to distinguish between tiny contrasting regions and carry out comprehensive mapping. Interpreting the data obtained is difficult, time-consuming, and expensive, and the measurement uncertainty is often significant. 

Conclusion

People can get information about the Earth via the use of remote sensing. It is thus necessary for the evaluation of risks, as well as the monitoring of land degradation and the preservation of natural resources. The system monitors extreme weather events such as hurricanes, earthquakes, and floods, and the data obtained may be processed to provide an analysis of the damage caused by natural disasters. The expenses associated with operating a remote sensing system may be rather high, particularly for smaller and less developed nations with limited financial resources, technological gaps, and a shortage of educated employees.

Frequently Asked Questions

1. What is remote sensing and examples?

The science of gathering information about an item or phenomena by detecting the radiation that is produced and reflected from it is referred to as remote sensing. There are two basic categories of equipment used for remote sensing.

2. What are four examples of remote sensing?

Film photography, infrared, charge-coupled devices, and radiometers are a few examples of several types of passive remote sensors. Active collection, on the other hand, involves the emission of energy in order to scan different things and places. After this, a sensor detects and analyses the radiation that is reflected or backscattered from the target item or area.

3. What are the characteristics of remote sensing?

A remote sensing system is defined by its primary components, which are an electromagnetic energy source, a transmission line, a target, and a sensor. These four elements work together to create the system. The Sun is one of several places where electromagnetic radiation may be found.