What technique is used to gather measurements on steep slopes?

The technique of breaking tape is particularly useful for gathering measurements on steep slopes, as it allows for accurate distance measurement over uneven terrain. This method involves using a tape measure that can be broken at intervals to manage the length effectively while maintaining high precision. When working on steep slopes, it can be challenging to measure directly due to the angle of the incline. Breaking the tape allows surveyors to measure horizontally, taking into account the slope more accurately, and ensures that the measurements reflect the true distance along the ground rather than a direct line of sight.

The other techniques mentioned are less suited for this specific scenario. Cross hairs are typically used in leveling and aiming instruments but do not assist in measuring slopes directly. Bucking-in is a technique applied to establish points or lines in surveying but is not specifically designed for measuring distances on steep inclines. Circular curves are related to the geometry of curves in road design and other applications, rather than directly assisting with slope measurements. Thus, breaking tape stands out as the most effective technique in this context.