A straight line behind the astronaut separates a brighter area from a darker area. The foreground is light and textured, while the background is darker, drab and smooth. They are separated by a relatively straight transition. Unlike the astronaut, the rover is not casting a shadow. The shadow side of the helmet is very bright.
Hills are a lighter shading than the plain.
The plain is a different colour and texture than the background hills. The ground is really bright near the shadow of the head of the astronaut taking the picture. The colour and shading change is abrupt and non-gradual at this transition. A very straight unnatural-looking line is found at the horizon before the hills. Left hill incline is also very straight.