Surveyors use theodolites to measure angles in the horizontal and vertical planes with high accuracy. This allows them to determine directions and elevations of various points on the land they are surveying. The data collected from theodolites is essential for creating maps, construction projects, boundary delineation, and other surveying applications.
In Vernier Theodolites, vernier are used for taking the readings. These theodolites are most commonly used in the general works. Most of the general Theodolites can read upto 20"
Transit theodolites (or just 'Transits') are those in which the telescope can rotate in a complete circle in the vertical plane, whereas the rotation in the same plane is restricted to a semi-circle for non-transit theodolites
They are surveying instruments used to measure angles.
Theodolites were used in old times for surveying, mapping, and construction projects. They helped measure horizontal and vertical angles accurately, allowing for precise calculations of distances and elevations. Theodolites were essential tools for creating detailed maps, designing infrastructure, and aligning structures with precision.
Frederick Marshall Johnston has written: 'Knights and theodolites'
Modern theodolites feature electronic displays for easy reading, built-in measurement software for accurate data collection, Bluetooth connectivity for data transfer, and some models may include tilt sensors for leveling. They also have increased accuracy and precision compared to traditional models.
Most theodolites have no "permanent" adjustments, since they are used to measure angles, both horizontal and vertical.
During Great Trigonometric Survey they used theodolites to measure Mount Everest.
A geodetic theodolite is a precise surveying instrument used to measure horizontal and vertical angles in geodetic surveying. It is designed for high-accuracy measurements required in geodetic surveying applications such as mapping, construction, and infrastructure development. Geodetic theodolites are typically equipped with electronic distance measurement capabilities for increased accuracy and efficiency.
Surveyors and engineers. Please see the related link that talks about theodolites, who uses them, how they work, and a few neat pictures:
Navigation technologies in the age of Heroic Exploration included sextants, theodolites and other celestial navigation tools.