The system of surveying in which the angles are measured with the help of a theodolite, is called Theodolite surveying.
Classification of Theodolites:
i) Transit Theodolite.
ii) Non Transit Theodolite.
i) Vernier Theodolites.
ii) Micrometer Theodolites.
iii) Modern Theodolite.
A theodolite is called a transit theodolite when its telescope can be transited i.e revolved through a complete revolution about its horizontal axis in the vertical plane.
In this type the telescope is cannot be transited. They are inferior in utility and have now become obsolete.
For reading the graduated circle if verniers are used, the theodolite is called as a Vernier Theodolite.
If a micrometer is provided to read the graduated circle the same is called as a Micrometer Theodolite. Vernier type theodolites are commonly used.
It is compact, light in weight, simple in design and can be used easily, virtually dust and moisture proof.