CST Level 1 Land Surveyor Certification Practice

What is a subtense bar primarily used for in surveying?

1. Measuring vertical angles

2. Determining level elevation at a point

3. Sighting targets that are precisely spaced apart

4. Calculating land area

The correct answer is: Sighting targets that are precisely spaced apart

A subtense bar is primarily used for sighting targets that are precisely spaced apart. It is a specialized measuring instrument that enables surveyors to gauge angles and distances more accurately. When the subtense bar is laid out between two points, surveyors can set up their instruments and take readings that help in determining horizontal distances and angles based on the known spacing of the targets at the ends of the bar. This precise spacing allows surveyors to enhance the accuracy of their measurements because it provides a consistent reference for determining angles and distances, especially in situations where direct measurements may not be feasible, such as across obstacles or over uneven terrain. The use of a subtense bar is crucial in surveys that require high levels of precision, such as in engineering or construction projects. By utilizing this tool, surveyors can effectively translate the position of their targets into accurate data that can be used for further calculations and assessments.