ABSTRACT
A large subset of the input domain of GIS constitutes images obtained from different sources and sensors. Images of Earth acquired through satellite or airborne platforms carrying sensors such as RADAR, thermal, infrared (IR), optical, microwave etc. are major input sources of GIS. All these platforms carrying the sensors acquire the image of the Earth’s surface corresponding to the IFOV (Instantaneous Field of View) of the sensors. These images have both the signature of the objects and the time stamp of the instance of the image acquired. These images are prone to various errors because of the instability of the platform acquiring the image, imprecise calibration of the sensors or due to radiometric disturbance in the atmosphere in between the sensors and the Earth’s surface. Therefore, removal of these errors is important to its further processing by GIS. Also registration of the images precisely with the area of the Earth’s surface is an essential prerequisite for effective analysis and measurement in a GIS environment.
