Introduction to theodolite, with diagrams

1. BOARD OF TECHNICAL EDUCATION
LUCKNOW
GOVERNMENT POLYTECHNIC KURSIROAD,
BARABANKI. Surveying II-Semester: V Covered Topic:
Theodolite SURVEYING

2. THEODOLITE SURVEYING
• The system of surveying in which the angles
are measured with the help
• of a theodolite, is called
• Theodolite surveying.

3. BASE ON ANGLE
• Vernier Theodolites: For reading the
graduated circle if Vernier's are used ,the
theodolite is called as a Vernier Theodolite
Micrometer Theodolites:
• If a micrometer is provided to read the
graduated circle the same is called as a
Micrometer Theodolite.
• Electronic digital theodolite: If electronic
distance measuring is attached with it then it's
call total station

4. SIZE OF THEODOLITE
• A theodolite is designated by diameter of the
graduated circle on the lower plate.
• The common sizes are 8cm to 12 cm while 14 cm
to 25 cm instrument are used for triangulation
work.
• Greater accuracy is achieved with larger
theodolites as they have bigger graduated circle
with larger divisions hence used where the survey
works require high degree of accuracy.

5. USES OF THEODOLITE
• Measuring horizontal and vertical angles.
• Locating points on a line.
• Prolonging survey lines
• .Setting out grades
• Finding difference of level
• .Ranging curves
• Tachometric Survey

6. TYPE’S OF THEODOLITE’S
• There are two different kinds of theodolites:
digital and non digital.
• Non digital theodolites are rarely used
anymore.
• Digital theodolites consist of a telescope that
is mounted on a base, as well as an electronic
readout screen that is used to display
horizontal and vertical angles.

7. Transit Theodolite
• A theodolite is said to be a transit one when
its telescope can be revolved through 180° in
a vertical plane about its horizontal axis, thus
directing the telescope in the exact opposite
direction

8. VERNIER TRANSIT THEODOLITE

9. PART’S OF A THEODOLITE

10. MAIN COMPONENTS OF A
THEODOLITE
1.Trivet 2.Foot Screws
3.Tri Branch 4.Leveling Head
5.Spindles 6.Lower Plate
7.Upper plate 8.Aframe
9.T Frame 10.Altitude
11Bubble 12.Compass
13.Tripod

11. Trivet
.
• It is a circular plate having a central, threaded
hole for fixing the theodolite on tripod
• It is also called the Centre line.

12. TRI BATCH
• It gives support the upper part of the
instrumental and attaches it to the tripod

13. Terminology
• Centering: Centering means setting the
theodolite exactly over an instrument station so
that its vertical axis lies immediately above the
station mark. It can be done by means of plumb
bob suspended from a small hook attached to the
vertical axis of the theodolite.
• Transiting : Transiting is also known as plunging or
reversing. It is the process of turning the
telescope about its horizontal axis through 180°
in the vertical plane thus bringing it upside down
and making it point , exactly in opposite
direction.

14. Swinging the telescope
• It means turning the telescope in the horizontal plane
about its vertical axis.
• Face Left: If the vertical circle of the instrument is on
the left side of the observer while taking a reading ,the
position is called the face left*
• Face Right: If the vertical circle of the instrument is on
the right side of the observer while taking a reading
,the position is called the face right
• Line of Collimation : It is also known as the line of sight
.It is an imaginary line joining the intersection of the
cross- hairs of the diaphragm to the optical centre of
the object- glass and its continuation.

15. HOW TO TAKE READING
WITH A VERNIER

16. FUNDAMENTAL AXIS OF A
THEODOLITE AND THEIR VIEW IN
RELATION’S