Theodolite is an essential equipment for surveying and mapping, and it is widely used in different fields. It is mainly used for measuring horizontal, vertical or slope distance and angle direction surveying of railway and highway engineering, geological engineering, building engineering and survey engineering.
Theodolite is an instrument that combines the principles of optics and geometry. It consists of a telescope, a circle, a lift and a pointer. The telescope is mounted on a tripod and can be rotated around the horizontal and vertical axes. The optical center of the telescope is installed on the center axis of the triangle. A graduated circle is installed above the center axis, which can also be adjusted 360°, and a plumb bob is attached to the lower part of the center axis.
A theodolite is mainly used to measure angles in the horizontal, vertical and diagonal directions. While the two-circle theodolite is mainly used to measure horizontal angles and vertical angles. The theodolite can measure angles in the horizontal and vertical directions through the two graduated circles and vertical pendulum on the support.
To measure the slope distance of elevation and depression, we need a direct-reading system. The two-circle theodolite can provide direct readings of the zenith and nadir angles, as well as the angles in the horizontal and vertical planes.
Modern digital theodolite can measure angles very accurately. It also can quickly store data by the internal computer and get the coordinates on the place any time, especially suitable for large-scale engineering. In addition, it can measure not only length, but also elevation and azimuth, and can store a large amount of data.
In summary, theodolites are important tools for surveying and mapping because they enable measurements of distance and direction. Theodolites have been improved in many aspects, and have become a sort of multi-purpose measurement instrument. With the development of technology of theodolites, their accuracy has been improved significantly, as well as general feasibility, allowing them to be widely used in different surveying and mapping projects.
