These procedures include radiometric correction to correct for
uneven sensor response over the whole image and geometric correction to correct for geometric
distortion due to Earth's rotation and other imaging conditions (such as oblique viewing). The
image may also be transformed to conform to a specific map projection system. Furthermore, if
accurate geographical location of an area on the image needs to be known, ground control
points (GCP's) are used to register the image to a precise map (geo-referencing).