What is Theodolite Surveying?

Theodolite Surveying is a type of surveying which is used to measure the angles in horizontal and vertical planes, it look like a telescope attached a magnetic compass into it which helps people to measure the angle between horizontal and vertical plane accurately, This instrument was discovered by a English Mathematician Leonard Digges in the Year around 1550. This tool is used by all construction professionals like Engineers, Architects and Builders to make sure that the structure what they are building (like : Buildings, Roads, Bridges and etc.) is at right place and at the right direction.

Components in a Theodolite

A theodolite is a precision instruments and have several components you can see the above figure for the reference of the component. Here are the main components of theodolite.

• Telescope: The Telescope is the most important and main part in the theodolite this telescope is only used for sighting the target or angle, the telescope has magnifying lenses and crosshairs for precise calculation and angle target.
• Objective Lens: This lens is located at the front of the telescope and the main objective of this objective lens is to gathers the light coming from the angle target.
• Eyepiece: The eyepiece is at the rear portion of the telescope and it is used to view the target through the lens.
• Vertical Circle: It is used to measure the vertical angle, and it is attached to vertical axis of a theodolite.
• Horizontal Circle: It is used to measure the Horizontal angle, and it is attached to Horizontal axis of a theodolite.
• Vernier Scale: The vernier scale is a secondary scale that is being used to increase the accuracy of angle measurements on the horizontal and vertical circles.
• Levelling Screws: The levelling screws are used to level the theodolite.
• Compass: Compass are equipped in theodolite to ensure the perfect angle.
• Tribrach: A tribrach is a platform which allow theodolite to attach to a tripod.
• Base Plate: The bottom part of theodolite lies/ sits on this base plate
• Optical Plummet: This Device is used for accurate centring of a point in theodolite.
• Battery Compartment: Many modern theodolites have a battery compartment for powering electronic components such as digital displays and laser pointers.

Uses of Theodolite Surveying

Theodolite Surveying is used is many ways as per our requirement in planning and measuring we are commonly using this instrument in :

1. Construction: In construction we use this instrument for accurate and straight measurement in a buildings, Bridges, Tunnel Etc.
2. Mapping: Surveyors uses this instruments to map new area and create a précised map out of the data.
3. Astronomy: Some other and advanced type of theodolite is used by astronomers to identify and locate stars and planet in our solar system.

Advantages of Theodolite Surveying

• Accuracy: Theodolites are very precise and accurate , so builders, Engineers and architects can be sure everything is in the right place according to the drawing or plan.
• Speed: A theodolite is faster in measuring angles this is faster than measuring with hand.
• Versatility: Due to use in different fields like in Construction, Mapping and Astronomy it is most versatile instrument in surveying.

Disadvantages of Theodolite Surveying

• Cost: Theodolites are expensive and is difficult to maintain.
• Skill: Theodolite requires a proper training and skill to get accurate measurements in a Survey.
• Setup Timing: The setup timing is too long for a theodolite, it is time consuming and can be used in long and complex projects.