nivellering

Nivellering is a surveying technique used to measure vertical differences between points and to establish a level reference plane. It is essential in construction, engineering, and cartography to ensure structures align horizontally and elevations are consistent. The term covers several methods, the most common being spirit leveling, differential leveling, and trigonometric leveling. In spirit leveling, a leveling instrument (such as an automatic or dumpy level) is used with a graduated leveling staff. A backsight determines the instrument height, and a foresight measures the height difference to the next point; repeating over a route yields elevations relative to a benchmark.

In differential leveling, a sequence of level lines is used to transfer elevations from a known benchmark to other points. Trigonometric leveling uses angles and distances to compute elevations, typically when direct leveling is impractical.

Equipment includes leveling instruments, leveling staffs, tripods, and benchmarks with known elevations. The process involves establishing a reference elevation, aligning the instrument, taking repeated backsights and foresights, computing reduced levels, and adjusting for curvature and refraction if high precision is required. Quality depends on instrument calibration, staff readability, and method consistency. The resulting elevation data support design grades, earthworks, drainage, and road or rail alignment.

Nivellering is also used in broader contexts to indicate leveling of differences in height or status, but in technical fields it refers to establishing a horizontal datum for height. See also datum, benchmark, reduced level, leveling.