This document provides an overview of surveying and leveling. It defines surveying as determining the relative positions of points on earth through direct or indirect measurements. Leveling is a branch of surveying that finds elevations of points with respect to a datum. There are various types of surveys classified by nature, object, or instruments used. Linear measurements can be direct via chaining or indirect using optical/electronic methods. Ranging is used to establish intermediate points when a survey line exceeds the chain length.

1. SURVEYING &
LEVELLING - I

2. FUNDAMENTAL
DEFINITION AND CONCEPT
 Surveying is the art of determining the relative
positions of points on, above or beneath the
surface of the earth by means of direct or indirect
measurement of distance, direction and elevation
 It also includes the art of establishing points by
predetermined angular and linear measurements.
 The application of surveying requires skill as well as
the knowledge of mathematics, physics and to some
extent astronomy.

3. Levelling deals with measurement in
a vertical plane
 Levelling is a branch of surveying
the object of which is
To find the elevations of points with
respect to a given or assumed
datum and
To establish points at a given
elevation or at different elevations
with respect to a given or assumed
datum.

4.  The knowledge of surveying is
advantageous in many phases of
engineering.
 The earliest surveys were made in
connection with land surveying.
 Practically every engineering
project such as water supply and
irrigation scheme, railroads and
transmission lines, mines, bridges
and buildings etc. require surveys.

5. OBJECT OF SURVEY
 The primary object of survey is the preparation
of a plan or map. The results of survey when
plotted and drawn on paper constitute a plan.
A plan is therefore the representation to some
scale, of the ground and the objects.
 The representation is called a map, if the scale
is small, while it is called plan, if the scale is
large, e.g. a map of INDIA, a plan of an estate
or a building

6. can be divided in to two classes
1.Geodetic surveying
2.Plane surveying
Geodetic surveying : Also known as
trigonometrical surveying
It is necessary to take into account the
curvature of the earth, since large distances and
areas are covered.
Shape of the earth is spherical, the line
connecting any two points on the surface of the
earth is curved or is an arc of a great circle
Primary Division of surveying

7.  Plane surveying :
In plane surveying the curvature of
the earth is not taken into account,
as the surveys extend over small
areas.
The earth’s surface is considered
as a plane so the line connecting
any two points as a straight line.
The degree of accuracy in this type
of surveying is comparatively low.
As a rough estimate, American
surveyors put the limit as 250 km2
for treating the surveys as plane.

8. CLASSIFICATION
Surveys may be classified in a variety of ways
1. Classification based upon the nature of
field of survey
a) Land surveys
b) Marine or navigation surveys : deals with
bodies of water for navigation purpose.
c) Astronomical surveys : This consists in
observations to the heavenly bodies such
as the sun or any fixed star.

9. 2. Classification based upon the object
of survey :
a) Archaeological surveys for
unearthing relics of antiquity
b) Geological surveys for determining
different strata in the earth’s crust
c) Mine surveys for exploring mineral
wealth such as gold, coal etc
d) Military surveys for determining
points of strategic importance both
offensive and defensive

10. 3. Classification based on instrument
employed in survey
a) Chain surveys
b) Theodolite surveys
c) Compass surveys
d) Plane table surveys
e) Tacheometric surveys
f) Photographic and Aerial surveys

11. PRINCIPLES OF SURVEYING
 The fundamental principles upon
which the various methods of plane
surveying are based
1. Location of point by measurement
from two points of reference.
2. Working from whole to part

12. Location of point by measurement
from two points of reference.
P
Q
R
P
Q
R
P
Q
R
Θ
P
Q
R
Θ
Φ
S
After deciding the position of any point, its reference must be
kept from at least two permanent objects or stations whose
position have already been well defined.

13. The purpose of working from whole to part is
To localize the errors and
 To control the accumulation of errors.
This is being achieved by establishing a hierarchy of networks of
control points. The less precise networks are established within the
higher precise network and thus restrict the errors. To minimize the
error limit, highest precise network (primary network) of control points
are established using the most accurate / precise instruments for
collection of data and rigorous methods of analysis are employed to
find network parameters. This also involves most skilled manpower
and costly resources which are rare and cost intensive.

14. LINEAR MEASUREMENTS
 There are various methods of
making linear measurements and
their relative merit depends upon the
degree of precision required
 Methods can be mainly divided into
three heads
1. Direct measurements
2. Measurements by optical means
3. Electronic methods

15.  In the case of Direct measurements,
distances are directly measured on
the ground with help of chain or tape.
 In the Optical methods, observations
are taken through telescope and
calculations are done for the
distances.
 In case of Electronic method,
distances are measured with
instruments that rely on propagation,
reflection and sub sequent reception
of either radio or light waves.

16. Direct measurements
 Various methods of measuring the
distances directly are as
1. Pacing
2. Measurement with passometer
3. Measurement with pedometer
4. Measurement by odometer and
speedometer
5. Chaining

17. Instruments for chaining
 Chain or Tape
 Arrows
 Pegs
 Ranging rods
 Offset rods
 Plumb bob

18. CHAIN

19. Chain
 Chains are formed of straight links of
galvanised mild steel wire bent into rings at
the ends and joined each other by three
small circular or oval wire rings.
 The end of the chain are provided with
brass handle at each end
 Various type of chains
1. Metric chain
2. Surveyor’s chain
3. Engineer’s chain
4. Revenue chain
5. Steel band

20. Metric chain
 Generally available in lengths of 5, 10,
20, 30 meters
 Tallies are fixed at every 5m and 10m
lengths and small brass rings are
provided at every meter length
 To facilitate holding of arrow in the
positions with the handle of chain, a
groove is cut on the outside surface of
the handle
 Length of the chains are engraved on
both the handles.

21. Tapes
Types of tape according to the material of which they are
made
1. Cloth or linen tape
Cloth tape of closely woven linen, 12 to 15mm wide
varnished to resist moisture, are light and flexible
Used for taking comparatively rough measurements
Commonly available in lengths of 10, 20, 25, 30 meters
A cloth tape is rarely used for making accurate
measurements because
 Easily effected by moisture and thus shrink
 Its length get altered by stretching
 It is not strong

22. Metallic tape
It is made up of varnished strip of waterproof
linen interwoven with small brass, copper or
bronze wires.
Does not stretch as easy as cloth tape
Available in lengths of 2, 5, 10, 20, 30 & 50
meters
Steel tape
A steel tape consists of a light strip of width 6 to
10 mm
Available in length of 1, 2, 10, 20, 30 and 50
meters.
A steel tape is delicate instrument and is very
light and therefore, cannot withstand rough
usage.
The tape should be wiped clean and dry after
using and should be oiled with little mineral oil,
so that it does not get rusted.

23. INVAR TAPE
Invar tapes are used mainly for linear
measurements of very high degree
of precision
Invar tape is made of alloy of nickel and
steel and has very low coefficient of
thermal expansion
The difficulty with invar tape is that they
are easily bent and damaged. They
must therefore be kept on reels of
large diameter.

24. Arrows
Made of steel wire and
generally 10 arrows are
supplied with a chain
An arrow is inserted into the
ground after every chain
length measured on the
ground
Arrows are made of good
quality hardened and
tempered steel wire 4 mm in
diameter.

25. PEGS
Pegs are used to mark the positions
of the stations or terminal points of a
survey line
Generally made of timber
They are driven in the ground with
the help of hammer

26. RANGING RODS
The length of the ranging rods
vary from 4 to 8 meters and
diameter from 6 to 10 cm
Generally large flag is provided
at top of the rod

27. Ranging out survey Lines
 While measuring the length of survey
line or chain line, the chain or tape must
be stretched straight along the line
joining its two terminal stations.
 If the length of the line is less than the
length of the chain, there will be no
difficulty, in doing so. If however, the
length of the line exceeds the length of
the chain, some intermediate points will
have to be established in line with the
two terminal points before chaining is
started.

28.  The process of fixing or establishing
such intermediate points is known as
Ranging.
 Two methods of ranging
(i) Direct ranging (ii) Indirect ranging

29. (i) Direct ranging
 Direct ranging is done when the two
ends of the survey lines are intervisible.
 Let A and B be the two points at the
ends of a survey line.
 Ranging rods are erected at points A
and B. The surveyor stands about one
meter away from point A as shown in fig.
 The assistant then goes with another
ranging rod and establishes the rod at a
point approximately in line with AB (by
judgment) at a distance not greater than
one chain length from A.
A P B
surveyor

30.  The surveyor at point A then signals
the Assistant to move transverse to
the chain line, till he is in line with A
and B.
 Similarly, other intermediate points
can be established.

31. (ii) Indirect or reciprocal ranging
 Indirect or reciprocating ranging is
done when both the ends of the
survey line are not intervisible due to
high intervening ground or due to long
distance between them.

32. A
M
N
B
A
M N
B
M1
N1
N2
M2

33. Chaining on uneven or
sloping ground
 For all plotting works, horizontal distances
between the points are required.
 It is, therefore, necessary either to directly
measure the horizontal distance between
the points or to measure the sloping
distance and reduce it to horizontal.
 There are two methods for getting
horizontal distance between two points.
(i) Direct method (ii) Indirect method