Question

The aerial photos with less than _____ degree tilt are considered as vertical photographs.

Hint:

Planes bounce around in the sky. As long as the camera doesn't tilt more than 3 degrees, mapping software can easily treat it as pointing straight down.

Answer 1

Step 1: Concept
Aerial photographs are classified into vertical and oblique based on the orientation of the camera axis relative to the ground.

Step 2: Meaning
A truly vertical photograph has an optical axis pointing straight down at exactly 90 degrees. However, maintaining a perfect 90 degrees in a moving aircraft is practically impossible.

Step 3: Analysis

• Due to aircraft roll, pitch, and yaw, almost all aerial photos have some unintentional tilt.
• In photogrammetry, an image with an unintentional tilt of $1^\circ$ to $3^\circ$ is practically treated and accepted as a vertical photograph.
• Photos intentionally taken with a tilt greater than $3^\circ$ are classified as oblique photographs.

Step 4: Conclusion
The standard threshold for an image to remain classified as vertical is less than 3 degrees of tilt. Final Answer: 3