A total station is an electronic theodolite combined with an electronic distance meter that has an additional internal data storage or external data collector. It works by measuring angles, distance, coordinates and heights. The data is transferred to a computer that uses software to generate a map of the area.
The total station emits a laser beam on a target and detects the light reflected back. The station calculates the actual deviation of the reflected light's wavelength. It has an accuracy of 0.07 inch per 0.62 mile. Direct line of sight is needed to measure the coordinates of an unknown point corresponding to a known coordinate. Some total stations use a Global Navigation Satellite System receiver to bypass the need of line of sight. GNSS offers a poor accuracy on the vertical axis and requires longer periods of time to take the measurement.