The correct answer is D. All the above.
A true vertical photograph is a photograph taken with the camera axis perpendicular to the ground surface. In this type of photograph, the principal point coincides with the plumb point, which is the point on the ground directly below the camera lens. The top of a hill appears on a truly vertical photograph at greater distance than its bottom from the principal point because the top of the hill is further away from the camera than the bottom of the hill. The top of a hill is represented on a vertical photograph at larger scale than the area of a nearby valley because the top of the hill is closer to the camera than the valley.
Here are some additional details about each option:
- Option A: The principal point coincides with plumb point on a true vertical photograph.
The principal point is the intersection of the optical axis of the camera and the image plane. The plumb point is the point on the ground directly below the camera lens. In a true vertical photograph, the principal point and the plumb point coincide.
- Option B: The top of a hill appears on a truly vertical photograph at greater distance than its bottom from the principal point.
In a true vertical photograph, the top of a hill appears at a greater distance than its bottom from the principal point because the top of the hill is further away from the camera than the bottom of the hill.
- Option C: The top of a hill is represented on a vertical photograph at larger scale than the area of a nearby valley.
In a vertical photograph, the top of a hill is represented at a larger scale than the area of a nearby valley because the top of the hill is closer to the camera than the valley.