The science of remote sensing has emerged as one of the most fascinating subjects over the past three decades. Earth observation from space through various remote sensing instruments has provided a vantage means of monitoring land surface dynamics, natural resources management, and the overall state of the environment itself. (Joseph, 2005)
Remote sensing is defined, for our purposes, as the measurement of object properties on the earth’s surface using data acquired from aircraft and satellites. It is therefore an attempt to measure something at a distance, rather than in situ. While remote-sensing data can consist of discrete, point measurement or a profile along a flight path, we are most interested here in measurements over a two dimensional spatial grid, i.e. images. Remote sensing systems, particularly those deployed on satellites, provide a repetitive and consistent view of the earth that is invaluable to monitoring the earth system and the effect of human activities on the earth. (Schowengerdt, 2006)
