ABSTRACT
The measurement of angles and distances is central to almost all land surveying activities, since from these observations it is possible to derive the relative positions and heights of points. Historically, angles have been measured using theodolites equipped with engraved metal or glass circles, and accuracies of a single second of arc have been achieved with such instruments. Recent developments in microelectronics, however, now enable these reading mechanisms to be replaced by electronic components. Also, the inclusion of microprocessors into the instrument design now allows a less rigorous observational procedure to be adopted without reducing the accuracy of the angular measurement. The basic principles and construction of these electronic theodolites are discussed in section 1.2.
