How do you determine the elevation of a point using a level instrument?

To determine the elevation of a point using a level instrument, measuring the difference in height from a benchmark is the fundamental method employed. A level instrument, when set up correctly, allows for accurate horizontal sighting and measurement of vertical angles, which is essential in land surveying.

The process begins with identifying a known benchmark, a point of established elevation. The level instrument is then positioned to take readings to the point whose elevation needs to be determined. By sighting through the level instrument, you establish a line of sight that is level. The difference in readings from this horizontal sight line to the height of the benchmark provides the necessary elevation measurement.

This method is favored because it relies on precise optical engineering, minimizing errors that can occur with estimates or averages. The accuracy and reliability of a level instrument make it the preferred choice for obtaining elevation differences in a surveying context.

Estimating elevations based on surrounding terrain or averaging heights from multiple reference points lacks the precision required for official surveying tasks, while calculating distances between benchmarks serves a different purpose, often used in triangulation or establishing control networks, rather than directly determining the elevation of a new point.