What does doubling the angle refer to in surveying practices?

Doubling the angle in surveying practices specifically relates to turning a horizontal angle. This terminology refers to the process where the angle measured between two lines or points is effectively doubled to ensure greater accuracy in the determination of bearings or directions within surveys. When a surveyor "turns" an angle, they may measure from a reference point to a target, then re-measure or adjust that angle either to confirm measurements or to perform necessary corrections. This technique is vital for improving the precision of the data collected and plays a crucial role in triangulation methods, which depend on the careful measurement of angles to ascertain positions and distances accurately in a surveying context.

The other options do not directly relate to the concept of doubling the angle as they involve either measuring angles, estimating distances, or working with area calculations, which do not encapsulate the specific act of turning or adjusting angles in the survey process.