The system of surveying in which the angles are measured with the help of a theodolite, is called Theodolite surveying.
Classification of Theodolites:
Primary
i) Transit Theodolite.
ii) Non Transit Theodolite.
Secondary
i) Vernier Theodolites.
ii) Micrometer Theodolites.
iii) Modern Theodolite.
Transit 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.
Non-Transit Theodolite:
In this type the telescope is cannot be transited. They are inferior in utility and have now become obsolete.
Vernier Theodolite:
For reading the graduated circle if verniers are used, the theodolite is called as a Vernier Theodolite.
Micrometer 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.
Modern Theodolite:
It is compact, light in weight, simple in design and can be used easily, virtually dust and moisture proof.