A theodolite uses a movable telescope to measure angles in both the horizontal and vertical planes. Traditionally they are manual instruments that come in two types – transit, which rotates in a full circle in the vertical plane, and non-transit, rotating in a half-circle. Total Stations use electronic transit theodolites in conjunction with a distance meter to read any slope distance from the instrument to any particular spot. They are hence two essential surveying instruments in one and when used with other technology such as mapping software are able to deliver the ‘total’ surveying package, from measuring to mapping.