Theodolite and level: similarities and differences

Any construction, regardless of its scale, cannot be successfully carried out without certain measurements in the built-up area. To facilitate this task, over time, man has created special devices called geodetic devices.

This group of devices includes various devices that not only resemble each other in design and functionality, but also differ, often radically. Striking examples of such devices are theodolite and level.

Both devices can be called necessary for construction work. They are used by both amateurs and professionals. But often inexperienced people have a question, what is the difference between these devices, and can they be interchangeable? In this article we will try to answer it. And at the same time we will tell you about the main features of both devices.

So let's take a look at both devices in turn and start with the theodolite.

Theodolite is an optical device from the geodetic group, designed to measure angles, vertical and horizontal. The main components of the theodolite are:

• limb - a glass disk with a scale image on which the degrees from 0 to 360 are indicated;
• alidada - a disk similar to a limb, located on the same axis around which it freely rotates, has its own scale;
• optics - objective, lens and reticule required for aiming at the measured object;
• lifting screws - used to adjust the device in the process of pointing;
• level system - allows you to install the theodolite in a vertical position.

You can also highlight the body, which houses the above-mentioned parts, a stand and a tripod on three legs.

The theodolite is placed at the apex of the measured angle so that the center of the limb is exactly at this point. The operator then rotates the alidade to align it with one side of the corner and record the reading in a circle. After that, the alidade must be moved to the other side and the second value must be marked. In conclusion, it remains only to calculate the difference between the readings obtained. The measurement always follows the same principle for both vertical and horizontal angles.

There are several varieties of theodolite. Depending on the class, they are distinguished:

• technical;
• accurate;
• high precision.

Depending on the design:

• simple - the alidade is fixed on the vertical axis;
• repetitive - the limb and alidade can rotate not only separately, but also together.

Depending on the optics:

• phototheodolite - with a camera installed;
• cinetheodolite - with an installed video camera.

Now let's talk about levels.

Level - an optical device from a geodetic group, designed to measure elevation points on the ground or inside erected buildings.

The design of the level is in many ways similar to the theodolite, but has its own characteristics and elements:

• optics, including a telescope and eyepiece;
• a mirror fixed inside the pipe;
• level system for installation;
• lifting screws for setting the working position;
• expansion joint for keeping the horizontal axis.

The level measures the height as follows. The device itself is installed at a point called an overview. All other measured points should be clearly visible from it. After that, in each of them, an Invar rail with a scale is placed in turn. And if all points have different readings, then the terrain is uneven. The height of a point is determined by calculating the difference between its position and the position of the survey point.

The level also has several varieties, but not as many as theodolite. These include:

• optical instruments;
• digital devices;
• laser devices.

Digital levels provide the most accurate results as well as ease of use. Such devices are equipped with special software that allows you to quickly process the recorded readings. Then they are saved on the device itself, thanks to the built-in memory.

Today, a variety of laser levels is widely used in construction. Their distinguishing feature is the presence of a laser pointer. Its beam is passed through a special prism, which is used instead of a lens. As a result, two such rays form perpendicular planes in space, intersecting with each other. They help to level the surface. Therefore, laser levels are often used for repairs.

A person who is not versed in measuring technology can easily confuse a theodolite with a level. And this is not surprising, because as we have already said, both devices belong to the same geodetic group of devices used for measurements on the ground.

Also, confusion can be caused by external similarity and the same elements that make up the devices. These include the visual system, which includes a reticule for guidance.

Perhaps this is where any significant similarities end. Theodolite and level have many more differences than you might initially think. Nevertheless, in some situations and under certain conditions, these devices can replace each other. But we'll talk about this a little later. Now let's look at the most important issue, namely, the distinctive features of theodolite and level.

So, as you already understood, the two devices under consideration have different purposes, albeit close in spirit. Speaking about the differences, first of all, you need to talk about the functionality of the devices.

Theodolite is versatile and allows you to make a variety of measurements, including not only angular, but also linear, in the horizontal and vertical planes. Therefore, the theodolite is more in demand for versatile construction.

The level is often called a highly specialized device. With its help, you can equip a perfectly flat surface. It is useful, for example, for pouring the foundation.

Accordingly, the designs of these devices also differ. The level has a telescope and a cylindrical level, which are absent in theodolite.

The devices differ from each other by the counting system. The level requires an invar rod for measurements., while theodolite has a two-channel system, which is considered to be more perfect.

Of course, the differences don't end there. They also depend on the models and types of devices. Thus, many modern theodolites have a compensator to increase the sighting potential.

Both devices have similar varieties, which include electronic theodolites and levels. But they are similar to each other only in that they provide a reverse image. Inside, each of them has its own characteristics.

The answer to this question is quite simple: it is better to choose both. Professional builders always have both devices in service. After all, theodolite and level perform different functions.

And yet, let's figure out which of the devices is better and what is its superiority.

We have already said that the theodolite is more versatile due to its versatility. In terms of the number of areas where it is used, the theodolite is noticeably superior to the level. These include astronomy, land reclamation, etc. In addition, the level can be used only on a horizontal plane, while theodolite works equally with both of them.

Reliability and high practicality are considered additional advantages of theodolite. Its huge pluses include the fact that one person is enough to carry out measurements. The level requires the participation of two people, one of whom will install the invar rail.

In some cases, the theodolite can even replace the level. To do this, you need to install it by fixing the telescope in a horizontal position. Next, you will also need a rail. but theodolite is unable to provide high accuracy... Therefore, it is used only in cases where only approximate data are needed.

But the level can also serve as a substitute for theodolite. To do this, you will have to supplement the device with a horizontal circle with degrees. In this way, it will be possible to measure horizontal angles on the ground. It is worth remembering that the accuracy of such measurements, as in the previous case, also suffers.

It can be concluded that objectively the theodolite is superior to his fellow man in many respects. Only they are not mutually exclusive. Theodolite cannot completely replace the level. This means that to perform serious construction or repair work, you will need both of these devices, which in certain situations will complement each other.

About which is preferable: theodolite, level or tape measure, see below.