What is the difference between a transit and a theodolite?

What is the difference between a transit and a theodolite?

Transits use vernier scales and external graduated metal circles for angular readings. Theodolites use enclosed graduated circles and angular readings are taken using an internal magnifying optical system. Theodolites tend to have a more precise reading and provide greater accuracy in measuring angles than transits do.

How do you find the horizontal angle using theodolite?


  1. Setup the theodolite over station Q and level it carefully.
  2. Set up the Vernier A to zero of the horizontal circle the horizontal circle usually graduated from 00 to 3600.
  3. Loose the lower clamp turn the instrument and then bisect the ranging rod at P.
  4. Check the reading of Vernier it should be same as above.

How do you adjust theodolite?

Use an adjusting pin to reset the bubble level adjusting screw so that the bubble returns exactly 1/2 the distance to the centered position. Re-level the theodolite with the leveling screws. Rotate the theodolite 180 degrees again, the bubble should maintain its position in the center.

What are the disadvantages of theodolite?

Errors due to leveling.

  • Inaccurate centering of theodolite instrument over station mark point.
  • Error due slipping of lower plate of theodolite instrument.
  • Taking reading wrong from vernier scale.
  • Errors occur due to parallax.
  • Errors due to not holding ranging rod vertically.
  • What is an EDM in surveying?

    Electronic distance measurement (EDM) is a method of determining the length between two points using electromagnetic waves. EDM is commonly carried out with digital instruments called theodolites.

    What tool do surveyors use?

    What equipment does a surveyor use? The main pieces of surveying equipment in use around the world are the following: theodolite, measuring tape, total station, 3D scanners, GPS/GNSS, level and rod. Most survey instruments screw onto a tripod when in use.

    How do you find the horizontal angle by theodolite?

    A Theodolite is a measuring instrument used to measure the horizontal and vertical angles….Measurement of Angle ABC

    1. The instrument is to be set over B.
    2. Lower clamp is then kept fixed and upper clamp is loosened.
    3. Telescope is then turned clockwise and vernier A is set to 0° and vernier B to approximately 180 degree.

    What are the three methods to measure horizontal angle?

    Choosing the most suitable method

    Section1 Method Horizontal angle
    3.1* Home-made graphometer Medium to large
    3.2** Magnetic compass Medium to large
    3.3* Compass or protractor All sizes
    3.3** Plane-table All sizes

    How do you calculate angles in surveying?

    Subtract the smaller bearing from the greater one. The difference will give the interior angle if it is less than 180°. But if the difference exceeds 180°, It will be exterior angle. Then obtain the interior angle by subtracting the difference from 360°.

    What are the errors in theodolite?

    Sources of error in theodolite work are classified into three groups: 1. Instrumental Errors 2. Observational Errors 3. Natural Errors.

    What is the most important surveying instrument?

    The most common surveying equipment is called a theodolite. Theodolites are used to measure the horizontal and vertical angles between points.

    • September 3, 2022