Foreshortening is an effect occurring principally in SAR images of mountainous areas, on slopes oriented towards the sensor when the distance between two points appears smaller than it would in flat areas due to the side-looking geometry. This results in a compression of the radiometric information. The area appears brighter.
Layover appears on very steep slopes, when the distance from the sensor to targets in the valley is larger than to the related mountain tops. The ordering of surface elements on the radar image is the reverse. This effect produces very bright features on the image.
Radar Shadow occurs on slope facing away from the sensor, if the slope angle is steeper than the sensor incidence angle. Shadow regions appear dark in the image, as no signal reaches them. Only small backscatter changes are principally due to system noise.