In terrestrial photogrammetry, the camera axis is generally oriented how?

• A. Horizontal
• B. Vertical
• C. Tilted 45 degrees
• D. Random

Answer: (A)

In terrestrial photogrammetry, keeping the camera axis horizontal helps keep the imaging setup level and the geometry predictable. A level axis means the perspective relationships between ground points and their image projections stay consistent as you move around the scene, which makes measuring distances and heights more reliable and simplifies the process of determining camera position and orientation (exterior orientation) and performing bundle adjustment. Tilting the camera up or down introduces varying vertical angles, increases foreshortening of tall objects, complicates calibration, and makes accurate scale and height measurements harder. A pronounced tilt, like 45 degrees, or a random orientation, would disrupt the straightforward relationship between ground coordinates and image coordinates, reducing accuracy and ease of reconstruction.