What does differential leveling help determine in surveying?

Differential leveling is a precise surveying technique primarily utilized to determine the difference in elevation between two or more points. It involves the use of a level instrument and graduated staff to establish a reference elevation at a benchmark and then measure the elevation of another point relative to this benchmark. By calculating the readings taken, surveyors can accurately ascertain the vertical difference between specific locations on the terrain.

This method is crucial because it provides the necessary data for various applications in civil engineering, construction, and land development. For instance, knowing the height differences is essential for designing drainage systems, roads, and building foundations. The distinction in elevation can influence how water drains, how structures are built, and how landscapes are altered.

In contrast, the other choices involve different aspects of surveying that are not directly linked to differential leveling. Calculating the total area of surveyed land pertains to land measurement techniques, determining horizontal distance involves a different set of measurements such as triangulation or tape surveying, and assessing the angle of land slope relates to slope analysis, which may use tools like inclinometers or theodolites, but not specifically differential leveling.