Surveying

Surveying is the art, science, and technology of determining or establishing the three-dimensional (3D; x, y, z) position of points on or beneath Earth's surface. Because geographic surveying deals primarily with topography, two other terms, topographic surveying and field surveying, are interchangeably used. Geographic survey data are used to produce topographic maps, block diagrams, and cross-sectional profiles and to establish vertical and horizontal controls such as spot heights and benchmarks.

Conventional geographic surveying uses theodolites, levels, chains, links, steel (or invar, a steel alloy) tapes, altimeters, compasses, clinometers, tachymeters, stadia rods, plane-table alidades, ranging poles, tripods, and the total station. Three basic sets of readings are taken during a conventional survey: distances, heights, and angles. Horizontal distance can be measured with a tape using slope distance ...