To measure the angles in horizontal and vertical planes ,various ​Survey Instrument in India ​are used. ​Digital Theodolite ​is one such precision instrument used primarily for survey of application and have been into use for field purposes like rocket launch technology and meteorology. There are both digital and non digital types of theodolite. Digital theodolite has a telescope which is mounted to it's base, along with this it has a screen which is mainly required to have the horizontal and vertical angles be displayed. Being digital and having the screen makes these more efficient than traditional measuring instruments as these give more accurate readings.

Parts & Working :

Similar to other measuring instruments, ​digital theodolite ​also has a telescope mounted at the base. The teles is further seen to have sight at it's top which is basically used to set the target. A focusing knob is attached that makes the sight of the object more clear. To locate the target, the telescope has an eyepiece for clear view. Opposite to the eyepiece, you can find an objective lens. This is effectively used to sight the object and the mirror inside the telescope magnifies the object. Combining the optical plummet, graduated circles and spirit, the theodolite is capable of finding horizontal and vertical angles while surveying.

The plummet ensure that the placing of theodolite is as effective as it's place just above the vertical planes.

The spirit is present to ensure that the device is at par with the horizon.

To efficiently survey all the horizontal and vertical angles, graduated circles are used.

Benefits of Theodolite :

On comparing theodolite with different​surveying instruments in India, ​theodolite are found to have a great deal of advantage that helps in measurements with higher accuracy and effectively within a given span of time.

Electronic Reading taken by digital theodolite ​ensures greater level of accuracy.
Having an internal magnifying system eliminates the need of having supportive instruments for different purposes.

Setting horizontal circles to zero is effective and quick.
Possibly the readings related to horizontal circles can either be left or right to the zero mark.

Having digital monitor reduces the need of multiple readings.

Having an internal optical instruments makes the theodolite have accurate readings. Since these theodolite eliminate the need of repeated reading, the entire procedure is quick and does not take much time. The major advantage is the presence of optical instruments as it makes the instrument more precise. They are not affected by winds and other related factors and also the fact that they can be used on plane and sloped surfaces turn them the best instrument for surveying.

Theodolite vs Transit Level :

Both the theodolite and transit are used for angular measurements offering almost the same level of accuracy. Yet there are few factors that differentiate both of them. Where transit utilizes vernier scales along with graduated metal circles located externally to measure angular readings , Theodolite has optical instruments built internally for angular reading and corresponding measurements. This in a way prices the fact that Theodolite have more precise readings with a higher level of accuracy as compared to transit.