Theodolite surveying and types of theodolite

 

THEODOLITE SURVEYING

·        A theodolite is a precision optical instrument for measuring angles between designated visible points in the horizontal and vertical planes.

·        The theodolite is used for land surveying, building and infrastructure construction.

·        It consists of a movable telescope mounted so it can rotate around horizontal and vertical axis and provide angular readings.

Types of Theodolite:

       I.          Transit Theodolite

     II.          Non-Transit Theodolite

      I.          Transit Theodolite

·    A theodolite is said to be a transit one when its telescope can be revolved through 180⁰ in a vertical plane about its horizontal axis, thus directing the telescope in exactly opposite direction.

·        In transit theodolite the vertical circle is rigidly fixed to the telescope and rotates with the telescope.

      I.          Non-Transit Theodolite

·        A Theodolite is said to be an Non-Transit theodolite when its telescope cannot be revolved through 180⁰ in a vertical plane about its horizontal axis.

·        This type is rarely used in the field.

Example: Y-Theodolite and Everest Theodolite