Digital theodolites differ in detail from the older venire models, although in general principals they are much the same. However, these are becoming popular because digital theodolites are light and compact and with a distomat attachment, these become an automatic total survey system.
At the touch of signal key angels and distance are measured and recorded directly in a solid state memory device. The data collected can be processed by a computer.
Digital theodolites are precise types of theodolite in which the horizontal and vertical angles are directly shown on the display panel of the instrument.
There requires and an external source of power i.e. battery of stipulated voltage while working with a digital theodolite. A separate keyboard is provided for the different operations of the theodolite.
The angle measurement is done by a photoelectric incremental rotary encoder which scans the motion of the telescope and registers the numerical value either horizontal or vertical angles in degrees, minutes and seconds.