We are independent & ad-supported. We may earn a commission for purchases made through our links.
Advertiser Disclosure
Our website is an independent, advertising-supported platform. We provide our content free of charge to our readers, and to keep it that way, we rely on revenue generated through advertisements and affiliate partnerships. This means that when you click on certain links on our site and make a purchase, we may earn a commission. Learn more.
How We Make Money
We sustain our operations through affiliate commissions and advertising. If you click on an affiliate link and make a purchase, we may receive a commission from the merchant at no additional cost to you. We also display advertisements on our website, which help generate revenue to support our work and keep our content free for readers. Our editorial team operates independently of our advertising and affiliate partnerships to ensure that our content remains unbiased and focused on providing you with the best information and recommendations based on thorough research and honest evaluations. To remain transparent, we’ve provided a list of our current affiliate partners here.

What Is a Theodolite?

By Phil Riddel
Updated May 21, 2024
Our promise to you
All The Science is dedicated to creating trustworthy, high-quality content that always prioritizes transparency, integrity, and inclusivity above all else. Our ensure that our content creation and review process includes rigorous fact-checking, evidence-based, and continual updates to ensure accuracy and reliability.

Our Promise to you

Founded in 2002, our company has been a trusted resource for readers seeking informative and engaging content. Our dedication to quality remains unwavering—and will never change. We follow a strict editorial policy, ensuring that our content is authored by highly qualified professionals and edited by subject matter experts. This guarantees that everything we publish is objective, accurate, and trustworthy.

Over the years, we've refined our approach to cover a wide range of topics, providing readers with reliable and practical advice to enhance their knowledge and skills. That's why millions of readers turn to us each year. Join us in celebrating the joy of learning, guided by standards you can trust.

Editorial Standards

At All The Science, we are committed to creating content that you can trust. Our editorial process is designed to ensure that every piece of content we publish is accurate, reliable, and informative.

Our team of experienced writers and editors follows a strict set of guidelines to ensure the highest quality content. We conduct thorough research, fact-check all information, and rely on credible sources to back up our claims. Our content is reviewed by subject-matter experts to ensure accuracy and clarity.

We believe in transparency and maintain editorial independence from our advertisers. Our team does not receive direct compensation from advertisers, allowing us to create unbiased content that prioritizes your interests.

A theodolite is a device for measuring horizontal and vertical angles. The traditional theodolite consists of a sighting instrument that can be rotated horizontally and vertically, and two calibrated circular plates, positioned so as to measure the amount of horizontal or vertical rotation in degrees. By pointing the sighting instrument, which can be a telescope, at an object, it is possible to measure its horizontal and vertical angles relative to suitable reference points. Normally, these would be true north for horizontal angles and the horizon for vertical angles. Theodolites have been used in navigation and astronomy and are today most commonly employed in surveying — either for building and construction or in geographical surveys.

When used for geographical surveying, a theodolite can help determine the distance and height of a feature, for example a hill or mountain. By measuring the horizontal angle, relative to true north, of the feature from two different locations a known distance apart, the distance can be calculated by trigonometry. Once the distance is known, the height can be determined in the same way by measuring the vertical angle of the feature relative to the horizon.

It is difficult to precisely identify the date on which the first theodolite was constructed, as throughout history a variety of devices bearing varying degrees of resemblance to a modern theodolite have been introduced. The earliest record of a device of this type dates from around 150 BCE in ancient Greece; it was called a dioptra and had two metal plates which could be rotated horizontally and vertically, along with a method of leveling involving tubes containing water. It was used for astronomical observations. The term “theodolite” first appeared in 1571 when the English mathematician Leonard Digges described an instrument for measuring angles called a “theoloditus;” however, it appears that it measured horizontal angles only. In 1653, William Leybourn, an English surveyor and author, provided a detailed description of a theodolite which could measure angles both horizontally and vertically and incorporated a compass as well as a sight.

Modern theodolites work on the same principles as their predecessors, but with improvements in precision and portability. They have telescopic sights and can measure angles with an accuracy of up to one tenth of an arc second. An electronic theodolite often incorporates an infrared device to measure distances and may have a processor and software to carry out calculations and store results internally or download them to a laptop or PC. This type of system is sometimes called a “total station.”

All The Science is dedicated to providing accurate and trustworthy information. We carefully select reputable sources and employ a rigorous fact-checking process to maintain the highest standards. To learn more about our commitment to accuracy, read our editorial process.

Related Articles

Discussion Comments
All The Science, in your inbox

Our latest articles, guides, and more, delivered daily.

All The Science, in your inbox

Our latest articles, guides, and more, delivered daily.