Fundamentals of Surveying (FS) Practice Exam

What does curvature error in leveling typically depend on?

1. The distance of the leveling shot

2. The temperature at the time of measurement

3. The humidity level

4. The weight of the leveling rod

The correct answer is: The distance of the leveling shot

Curvature error in leveling is primarily influenced by the distance of the leveling shot. This error arises because of the Earth's curvature; as the distance between the leveling instrument and the target increases, the line of sight deviates from a true horizontal plane due to the curvature of the Earth. The greater the distance, the more pronounced the curvature effect becomes, necessitating corrections to ensure accurate measurements. While temperature, humidity, and the weight of the leveling rod can affect leveling measurements in various ways, they do not specifically influence the curvature of the Earth's surface. Temperature and humidity can impact the refraction of light, potentially altering the perceived position of the leveling rod, but these factors are not the fundamental cause of curvature error. The weight of the leveling rod may affect stability and precision in some contexts, but it does not relate to the curvature of the Earth itself. Thus, the distance of the leveling shot is the critical factor in determining curvature error.