Fundamentals of Surveying (FS) Practice Exam

What error does temperature change significantly affect in surveying instruments?

1. Collimation error

2. Parallax error

3. Rod plumb error

4. Measurement error

The correct answer is: Measurement error

Temperature changes significantly affect measurement error in surveying instruments primarily due to their impact on the materials and components of the equipment being used. When temperature fluctuates, the physical properties of materials, such as expansion and contraction, change as well. For instance, steel tapes, leveling rods, and other measuring devices can expand or contract, leading to inaccuracies in the measured lengths or angles. As temperatures rise, a material like a steel tape may elongate, while cooler temperatures may cause it to shorten. Similarly, optical components such as lenses in total stations can also be affected by temperature changes, which may distort readings taken from a distance. Therefore, it becomes crucial for surveyors to take temperature into account and apply corrections—such as using temperature coefficients or converting measurements to a standard temperature—to ensure accuracy. Other types of errors, such as collimation or parallax errors, are less influenced directly by temperature changes and are more related to the calibration and alignment of the instruments or the manner in which readings are perceived by the operator. Similarly, rod plumb errors pertain to the positioning of the rod itself rather than any thermal effects on the materials. Understanding the implications of temperature changes is essential for maintaining precision in measurements and ensuring high-quality survey results.