Spectral Indices Across Remote Sensing Platforms and Sensors Relating to the Three Poles:
An Overview of Applications, Challenges, and Future Prospects
With advances in remote-sensing technology and higher-quality products, the field of spectral indices has experienced a sizeable progressive evolution. These spectral indices computed by using different brands of remote-sensing products and applying additive, subtractive, or normalizing operations, have been and are being devised to detect diverse objects in various spheres of our planet. For instance, there are spectral indices that detect and delineate plant leaf moisture, that biome comes under biosphere, at distinctive spatial scales. There are other indices that are used to extract elements from the lithosphere like iron oxide content, or to show clay mineral content, etc. Similarly, there are spectral indices to detect various elements which constitute other spheres of our planet. In this work, we have used the Web of Science (WoS) database from 1999 to 2022 and searched for only English language research journals, book chapters, books, and scientific reports. We found 2227 documents in all the categories to perform a systematic, scientometric review regarding spectral indices used for the identification of elements constituting various objects of the five different spheres. The primary objective of this chapter is to present a systematic and scientometric review of spectral indices used for quantification of different elements of all the spheres of our planet relating to lithosphere, hydrosphere, atmosphere, biosphere, and anthroposphere, across remote-sensing platforms and sensors. The study also examines the rationale of spectral indices across the ever-advancing remote-sensing platform and sensors, and their future challenges, and investigates the challenges and prospects of this domain of study. This study will be useful for acquainting new researchers with the use spectral indices for their specific objectives.