Total Station

A total station is an electronic surveying instrument that combines an electronic theodolite (for horizontal and vertical angles) with an electronic distance measurement (EDM) unit and an onboard processor, so it measures angles and distances to a prism/target and computes 3-D coordinates (easting, northing, level) directly, storing them digitally. It is the standard instrument for construction setting-out, topographic survey, as-built/quantity survey and deformation monitoring, having largely replaced the separate theodolite-and-tape workflow.

Its accuracy and speed make precise grid setting-out, level transfer and the staking of column/foundation points routine, and data flows directly between the instrument and CAD/BIM, reducing transcription error. Reliable results still depend on correct instrument setup (centring, levelling), known/checked control points and benchmarks, atmospheric/prism-constant corrections and traverse closure checks — the instrument removes arithmetic error, not procedural error. Robotic and reflectorless total stations extend it to one-person operation and to points where a prism cannot be placed.