What is a Surveyor’s Theodolite, and How do You Use One?

Surveyors use theodolites to measure distances and angles. This may sound like a simple task, but there is more to it than meets the eye. The surveyor must also consider how far away they are from the object getting measured, as well as any objects that might get in the way of their line of sight when looking through the scope lens.

If you want to know how surveyors use a theodolite or what one is, this article is for you!

These measurements get used to plot boundaries, buildings, and utilities. Surveyors use theodolites to measure out distance manually, typically using a chain or metal measuring tape. Land students learn the basics of angle measurement using a theodolite. Job surveying requires the use of more advanced surveying instruments.
Place the nail at the point where you want to set up the instrument. This instrument will measure the angle and distance of various points.

Attach the tripod to the instrument and set its height so that you are at a comfortable eye level with the device. Be sure to have the hole on the mounting plate centered over the nail. First, set the tripod at a comfortable height by adjusting it to your measurements. You can do this by pressing each leg into the ground and standing on the brackets at the bottom of each leg and looking down through the telescope to reach eye level with your target.

See that the tripod’s mounting plate is at eye level for a stable position. Remove the theodolite from the case. A surveyor’s theodolite is heavy, and most come with an attaching knob on top. Lift it by grasping the knob. Extend it until it sets down in a sturdy spot and screw on the mounting plate below it.

The theodolite is a telescope on top of a tripod. To level it, loosen or tighten the screws at each leg to bring the telescope faces parallel with one another to detect vertical and horizontal angles accurately.

Adjust the vertical plummet at the bottom of the theodolite. The small sight is called a vertical plummet. With this sight, you can ensure the instrument gets centered over the nail. Fine-tune the vertical plummet by adjusting the knobs on the bottom.

Hold the scope in one hand and focus on a point to measure with your crosshairs. Even with a good lock, theodolites can be challenging to use. You need to find an exact and stable point to measure because otherwise, errors are introduced into your measurements. To do so, twist the locking knobs on one of the leg-like parts until it is securely locked in place. If the two measures are close together, adjust the instrument until the two areas on the viewing scope are next to one another.

Learn from A Licensed Surveyor

Before acquiring a theodolite, you should enroll in coursework from a licensed surveyor. The hands-on experience is indispensable for understanding the more abstract concepts associated with math and instrument operation.

Equipment Warnings

Keep the instrument away from rough surfaces and handle it gently. A lot of care is needed when transporting or operating a theodolite due to these precision measuring devices being sensitive.