GENERATION OF ORTHOIMAGE USING AERIAL PHOTOGRAPHS AND PAN DATA

Abstract

Maps are required for various purposes such as planning, designing and execution of engineering projects. These maps are prepared by conventional methods with different surveying techniques. Now a day's remote sensing data such as satellite image and aerial photographs are using to update the maps. But these remotely sensed data contains geometric errors, caused by scale variation or relief displacement, sensor attitude/orientations and internal sensor errors. These errors can be removed by a process cause orthorectification. Once these satellite images and aerial photographs have been orthorectified it is commonly refereed as orthoimage. Orthoimges can play a vital role in resource surveys as they show the terrain in fine detail. Good orthophotos provide invaluable high-resolution information for resource planners. Digital Photogrammetry is the replacement of conventional methods to overcome the problems facing with conventional methods such as time consuming, conventional instruments are require large space and operational cost is also high. Recent developments in Digital photogrammetric technique can be used to develop precisely Orthorectified air photos and satellite images quickly cheaply and easily. Orthophotos themselves contain no information regarding elevations. They can, however, serve as planimetric base maps up on which elevation contours are super-imposed, and the resulting product termed as topographic orthophotomap. Orthophotos can be used as maps without cartographic treatment, or they can be enhanced and supplemented with lines, symbols, names, etc.