By Remote sensing, we understand that it is the process of collecting data of an object or a phenomenon without the actual physical presence. The data which is collected is frequently done mostly with the help of aerial technologies like airplanes or satellites or any other aerial objects that are equipped to use advanced sensor technologies to detect energy that is reflected from the object. The spatial data is collected for further investigations.
Remote sensing technology makes it possible to collect data from great distances and even from areas that are not accessible by humans at all. There are two modes of remote sensing; active and passive remote sensing. Active remote sensing is one where the aerial sensors emit radiation to the object or place that is being studied and collects the data of the radiation that is reflected by the object. On the other hand, passive remote sensing is based on the object reflecting back radiation that is from a natural source like that of the sun. These data are collected by various orbital platforms like satellites, airplanes, weather balloons etc and transmit data to various terrestrial stations where the data and images are processed to be analyzed or archived.
Related: Remote Sensing and GIS
There are various technologies and applications where the satellite imagery along with the data is widely used. Few technologies are:
- Laser and radar altimeters allow imagery and data collection in all weather conditions
- Light detection and ranging technology allow a 3-dimensional study of the object or area.
- Multi-spectral and hyperspectral imaging provides very high-resolution data
- Conventional radar
- Stereographic image comparison technology helps in delineation and assessment of density
The use of these various technologies of remote sensing allows researchers to get more accurate readings about dimensions and movements of the area or object under study. With the use of advanced technology, a more targeted study and analysis are possible nowadays which gives an enhanced inference of what is recorded or observed.
A wide variety of data can be derived from the satellite imageries. Both forms of remote sensing; active and passive can operate from microwave to the ultraviolet regions of the electromagnetic spectrum allowing a wide range of data to be collated about the earth surface. There are many different satellite systems that constantly record information. Each of these systems can be differentiated based on the spatial, spectral, radiometric and temporal resolution.
The data from the satellites cover larger areas of land which makes easy availability of data for various features of that location. These orbital sensors ensure regular updating of the imagery and data for almost all the locations of the globe in an automated way without the involvement of any human intervention. The digitally and geometrically accurate data can be easily used to interpret other related data for analysis or research.
Let us now have a look at its wide areas of applications
Remote sensing is applied in various fields which include most earth science disciplines, geography, land survey, military, intelligence, weather predictions, drought etc. Let us have a close see on few of its applications below.
- Agriculture: It is one of the best ways to assess the agricultural viability in terms of crops and soil. Satellite data is extensively used in precision farming to manage and monitor farming processes at different levels to optimize and manage any technical operations that might be required as well. Remote sensing is a great way for crop type classification, assessment, and yield estimation. It also helps in mapping soil type and characteristics including the study of erosion and moisture content so that the suitability of crops can be assessed along with enhanced management practices. You can collect the soil data along with the satellite imageries of few of the years of a particular area and also predict and suggest best crop growth on the basis of the remote sensing data. This would highly help the farmers for understanding and growing their crops in accordance with the soil type and climatic change. Moreover, future predictions would also be possible based on the data of weather change and soil type. Soil erosion maps can also be assessed using the imageries for any particular location.
- Forest mapping: Traditional ground surveys of the forest is not always feasible or a viable option. In these cases, remote sensing technology helps in a great way to map, identify and delineate various forest types. Using remote sensing, a large area of the forest can be studied, and the species can be identified with very specific details including tree type, height and density. With high-resolution data and satellite imagery, the texture and leaf density too can be assessed to determine any infestations or stresses on the trees. With the possibility of clear-cut mapping of the forested areas, the extent of deforestation and its implications can be understood better. Moreover, through the remote sensing data, the forest fire assessment can be done in which you would get to know the details of the area in which it has been affected as the color of the burnt leaves would leave a trace in the satellite data than the normal greens leaves. Another use can be the settlement of the area done by cutting the forest area. You can clearly get the picture of deforestation from the subsequent data.
- Weather assessment: The spaceborne remote sensing system provides invaluable information on the earth’s atmosphere system covering a wide area and in a continuous manner. This allows for accurate and real time meteorological and climatological study to be carried out across the world. The satellite-based sensors have greatly enhanced the understanding of the earth’s atmosphere system. These studies allow for timely temporal prediction and assessment of upcoming storms, cyclones and other weather conditions. Predictions and necessary measure too can be done using remote sensing data for natural calamities. Also, through the remote sensing data, you can determine the rise of global warming under a few decades. Draught is another measure with can be easily measured by the remote sensing data. With the climatic change and data from different years, you can get to know the future condition of draught.
- Civil engineering study: Remote sensing technology also offers a wide range of application in the field of Civil Engineering which would allow a proper study of the landscapes and will facilitate proper planning and urban development. Site investigations can be done with regards to water resources, hydrological models, natural hazards and other changes which could impact any settlement in the area. With all safety measures taken into consideration of the surrounding, you can have factories situated. No environmental balance would be disturbed if checked properly.
- Land Use Land Cover: Remote sensing is extensively used for the assessment of land use and land cover. With the help of the satellite imageries with a combination of different bands, you can easily differentiate settlements and land covered from the imageries. With comparing from the multi-aged data, the percentage of settlements, deductions of forestry and rise in human intervention in nature can be easily assessed.
- Military Surveillance: One of the major applications of remote sensing can be used in military surveillance. With the help of the satellite imagery, military settlements can be easily assessed which surely helps in maintaining the peace and harmony. Moreover, if required the imageries can be used by the government.
- Glacier Melts and Effects: Another application of remote sensing is the meltdown of the glaciers and their effects on the sea level. You can easily assess the effects of global warming and alarming symptoms of the rise of the water sea level and its effects through the study of the satellite imageries data. Through this study, safety measures can be taken beforehand.
- Assessing the Rural Road: with the help of the satellite imageries, you can easily distinguish the rural road conditions of any particular area. In accordance with the population, you get a clear picture of the road conditions and this can be an immense help for urbanization. By having a clear picture and assessment of the conditions, the government would easily take necessary action for it. In accordance with GIS and the remote sensing data, assessing the rural roads makes is much easy and saves a lot of time and money of transportations.
Conclusion: This is not an exhaustive list of application that remote sensing offers. Remote sensing can be used in many other aspects. With the development of various software that enhances the interpretation of the data and analysis, remote sensing technology has entered a new era with better tools and comprehensive systems that allows for detailed studies and assessment with ease and accuracy. The satellite imageries can be interpreted in many different ways along with the GIS software’s and can be used extensively.