The science of gathering information about a distant object without making any physical contact with it is called remote sensing. It makes use of different kinds of sensors to observe the Earth and other planetary bodies. Remote sensing measures the radiation emitted and reflected by an area to analyze its physical characteristics. The sensors can be classified into active and passive sensors. Active sensors respond to internal stimuli while the passive sensors use external stimuli. They record the natural energy which is reflected from the Earth's surface. The important characteristics of data which is collected are spatial resolution, spectral resolution, radiometric resolution and temporal resolution. The field of remote sensing finds extensive application in the fields of geography, land surveying, intelligence, economics and commercial planning. The topics included in this book on remote sensing are of utmost significance and bound to provide incredible insights to readers. Different approaches, evaluations, and methodologies of remote sensing have been included herein. This book is a complete source of knowledge on the present status of this important field.