Remote sensing is defined as the science and art of acquiring information about material objects without being in touch with them. These measurements are possible with advanced airborne and space-borne remote sensing platforms and sensors that are capable of observing any part of the world frequently with various details. It is discovered that each earth cover has its own spectral reflectance characteristics. The characteristics are so unique that they are called “signature” which enable us to discern the objects from its intermixed background. The final remote sensing process is completed by the analysis of the data using image interpretation and image processing techniques. Some key elements, or cues from the imagery, such as shape, size, pattern, tone or colour, shadow and association, are used to identify a variety of features on earth. The techniques of image interpretation can be further enhanced by the techniques of image processing that can restore, enhance and extract geographical information from original remote sensing images. These altogether yield valuable information on earth resources and living environment of human beings.