Page 22 - ebook_soil engineering practical workbook_15112021

2 THEODOLITE

2.1 Experiment outcomes

At the end of the lab session students should be able:
 to identify name and function of each component of theodolite.
 to use theodolite properly.
 to determine the measurement of horizontal angles.

2.2 Theory

The theodolite is the most intricate and accurate instrument used for
measurement of horizontal and vertical angles. It consists of telescope by
means of which distant objects can be sighted. The telescope has two distinct

motions on in the horizontal plane and the other in the vertical plane. The
former being measured on a graduated horizontal vertical circle of two

vernier. Theodolite are primarily classified as transit theodolite and non-
transit theodolite. A theodolite is called transit theodolite when its telescope

can be resolved through a complete revolution about its horizontal axis. In a
vertical plane, the transit type is largely used.

Theodolite is an instrument designed for the measurement of horizontal and

vertical angle. It is most precise method it is also used for laying of horizontal
angles. Locating points on line prolonging the survey line establishing the

gradient, determination of difference in the elevation setting out curve
.Theodolite are of two types transit and non transit. Transit theodolite is
commonly used now a days . Transit theodolite telescope can be revolved a

complete revolution about its horizontal axis in a vertical plane. A transit
theodolite consists of essential part.

14 | Soil Engineering Practical Workbook