Surveying Complete Notes of Unit 1.pptx

Department of Civil Engineering
Subject- Surveying (3CE4-05)
Semester/ Year – 3/ 2
By
Denis Jangeed

Subject Weightage (as per previous patterns)
Exam Marks Weightage
GATE 4-6 Marks out of 100
State JE/Aen 10% of total Weightage
SSC JE 10% of total Weightage
ESE/IES (Objective) 18-22 marks out of 300
ESE/IES (Conventional) 60-75 marks out of 600
Books
1 Surveying volume-I & II by Dr. B.C. Punmia
2 Surveying volume-I & II by S.K. Duggal
By :-Denis Jangeed

Chapter- 1
Objective of Surveying:-
To determine the relative position of any objects or points
of the earth. To determine the distance and angle between
different objects. To prepare a map or plan to represent an
area on a horizontal plan.
Scope of Surveying:-
⮚ The planning and design of all Civil Engineering projects
such as construction of highways, bridges, tunnels, dams etc
are based upon surveying measurements.
⮚ During execution, project of any magnitude is constructed
along the lines and points established by surveying.
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Outcomes:-
⮚ Students understand the basics of linear and angular
measurement.
⮚ To make students understand the measurement of level
and contour maps.
⮚ To introduce different Types of curves, setting out of
curves.
⮚ To brief students to different systems of tachometric
measurements.
⮚ To Setting out works & modern field survey systems.
By :-Denis Jangeed

Chapter-2
LINEAR AND ANGULAR MEASUREMENTS
Introduction of Surveying:-
❖As Per Dictionary Surveying = Collection of data
❖Surveying is the art/process of determining the
relative positions of any points on, above or
beneath the surface of the earth by performing
linear (Distance) and angular measurements.
❖And preparing a Plan & Map to any suitable scale.
❖Both Plan & Map are the graphical representation of the
features on a horizontal plane.
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Basic Definitions in Surveying:-
Main Station=PQRS
Main Survey Line=PQ, QR,RS, SP
Base Line=QS
Tie Station/subsidiary Station=
a,& b,
Tie Station/subsidiary line= ab
Tie Line= VU,
Check line =PT, RW
Offsets- 1-2, 3-4, 5-6, 7-8,9-10
a
b
W
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Plumb Line
Plumb
bob
Plumb Line
Self Weight W
Working on gravity of earth
C
O
In Geodetic survey plumb lines
are concentric.
Means all lines meet at centre of the earth
By :-Denis Jangeed

Dimension of the new shape
Scale factor = Dimension of the original shape

Classification of Surveying
Surveying may be classified on the following basis:-
1. Nature of the
survey field
2. Object
of survey
3. Instruments
used
4. The methods
employed
a). Land survey
b). Marine or Hydraulic
c). Astronomical survey
1. Topographic Survey:
2. Cadastral Survey:
3. City Survey
1. Engineering Survey
2. Mine Surveying
3. Archaeological
4. Military surveying
5. Geological Surveying
1. Chain surveying
2. Compass surveying
3. Plane table surveying
4. Theodolite surveying
5. Tachometric surveying
6. Photographic surveying
(i) Triangulation surveying
(ii) Traverse surveying
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a). Land Survey:- It involves measurement of various
objects on land.
This type of survey may be further classified as given
below:
1. Topographic Survey:
It is meant for plotting natural features like rivers,
lakes, forests and hills as well as man made features
like roads, railways, towns, villages and canals.
2. Cadastral Survey:
It is for marking the boundaries of municipalities,
villages, districts, states etc. The survey made to mark
properties of individuals also come under this category.
By :-Denis Jangeed

3. City Survey:
The survey made in connection with the construction of streets,
water supply and sewage lines fall under this category.
b). Marine or Hydrographic Survey:-
Survey conducted to find depth of water at various points in bodies
of water like sea, river and lakes fall under this category. Finding
depth of water at specified points is known as sounding.
c).Astronomical Survey:-
Observations made to heavenly bodies like sun, stars etc., to locate
absolute positions of points on the earth.
By :-Denis Jangeed

2. Classification based on object of survey:-
⮚ Engineering Survey
⮚ Mine Surveying
⮚ Archaeological surveying
⮚ Military surveying
⮚ Geological Surveying
⮚ Engineering surveys:-
The objective of this type of survey is to collect data
for designing civil engineering projects like roads,
railways, irrigation, water supply and sewage
disposals.
By :-Denis Jangeed

⮚ Mines Surveying:-
This is used for exploring mineral wealth.
⮚ Archaeological Survey:-
This survey is for unearthing relics of antiquity.
⮚ Military Survey:-
This survey is meant for working out plans of strategic
importance.
⮚ Geological Survey:-
This survey is for finding different strata in the earth’s
crust.

3. Based on Instruments used:-
⮚Chain surveying
⮚Compass surveying
⮚Plane table surveying
⮚Theodolite surveying
⮚Tachometric surveying
⮚Photographic surveying
⮚ Chain surveying:-
▪ The chain survey is the simplest method of surveying.
In the chain survey, only measurements are taken in
the field.
▪ Only linear measurements are made i.e. no angular
measurements are made.
▪ This is most suitably adapted to small plane areas with
very few details.
By :-Denis Jangeed

Chain Details
By :-Denis Jangeed

⮚ Compass Surveying:-
Compass surveying is the branch of surveying in which
the position of an object is located using angular
measurements determined by a compass and linear
measurements using a chain or tape.
⮚ Plane Table Survey:-
• The plane table surveying is the fast method of
surveying. In this type of surveying plotting of the plan
and field observations can be done simultaneously.
• In case of plane table surveying Geometrical
conditions of site are manuscript in the map sheet
using plane table and alidade after that topographic
details are arranged on the map.
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Plane Table:-
By :-Denis Jangeed

⮚Theodolite Survey:
The Theodolite is an instrument that can measure both
horizontal and vertical angles.
By :-Denis Jangeed

⮚ Tacheometric Survey:-
▪ Tacheometry is a branch of angular surveying in which
the horizontal and vertical distances are obtained by
optical means as opposed to the ordinary process of
chain and tape.
▪ This is done with the help of two special type of
instruments- transit Theodolite and stadia rod.
⮚ Photographic surveying:-
▪ Photogrammetric surveyors specialize in the science of
obtaining reliable spatial information from
photographic images.
▪ Photogrammetrists analyze aerial and terrestrial
photographs to obtain information about physical
objects and the environment
By :-Denis Jangeed

4. Classification based on methods used:-
Based on methods adopted, surveying can be categorized into:
(i) Triangulation surveying
(ii) Traverse surveying
(i) Triangulation:-
In this method control points are established through a
network of triangles.
(ii) Traversing:-
In this scheme of establishing control points consists of a
series of connected points established through linear and
angular measurements. If the last line meets the starting point
it is called as closed traverse. If it does not meet, it is known as
open traverse
By :-Denis Jangeed

⮚Methods of Linear measurements:-
Various methods used for linear measurements may be
grouped as
(i) Approximate (Direct measurement)
(ii) Chaining
(iii) By optical means
(iv) Using electromagnetic distance measurement
instruments
(i) Approximates Methods of Linear (Direct) Measurements:-
These methods are used in reconnaissance survey. On
smooth roads they can give results within 1 per cent error.
These approximate measurements may be by
(a) Pacing
(b) Passometer
(c) Pedometer
(d) Odometer
(e) Speedometer
By :-Denis Jangeed

(a) Pacing:
▪ In this method surveyor walks along the line to be measured
and counts the number of steps.
▪ The distance measured = Number of steps × average length of
a step.
▪ Average length of a step can be found by walking along a
known length. A normal man takes a step of length 0.75 m to
0.8 m.
By :-Denis Jangeed

(b) Passometer:
▪ A Passometer is a watch-like instrument which is carried
vertically in the pocket of shirt or tied to a leg.
▪ It records number of steps taken. Thus the problem of counting
number of steps is eliminated in this approximate method of
linear measurement.
Passometer
By :-Denis Jangeed

(c) Pedometer:
▪ This instrument is similar to Passometer but it can record the
distance instead of number of steps.
▪ In this, zero setting and setting of step length is made before
walking.
Pedometer
By :-Denis Jangeed

(d) Odometer:
▪ This instrument is attached to the wheel of a cycle or other
vehicle.
▪ It records the number of revolutions made by the wheel.
Knowing the circumference of the wheel, the distance
travelled may be found.
By :-Denis Jangeed

(e) Speedometer:
▪ Its gives us Speed & Distance both & tip also.
▪ Odometer calibrated to give distance directly is called
speedometer.
▪ This is to be used for particular vehicle only.
By :-Denis Jangeed

Accessories used in Chain Surveying
Pegs
▪ Wooden pegs of 15cm length and 3 cm square in
section are used to establish the main station
points or the end points of a line on the ground.
▪ They are tapered one end and are driven into the
ground by using a wooden hammer.
▪ About 4 cm is left projecting above the ground.
By :-Denis Jangeed

Arrow- Chain Pins
▪ Chain pins or arrows are used with the chain
for marking each chain length on the ground.
▪ The arrow is driven into the ground at the
end of each chain length is measured.
▪ Chain pins the arrow should be made of
good quality hardened and tempered steel
wire of minimum tensile strength of 70
kg/mm
2.
▪ The overall length is 400 mm and
thickness is 4mm.
▪ The arrow has a circular eye at the one end
is pointed at the other end .
▪ Mostly used for intermediate station
By :-Denis Jangeed

Ranging Rod/Pole or Picket
By :-Denis Jangeed

Ranging Rod
▪ Ranging rod is used for ranging or aligning long lines on the
ground in field surveying.
▪ Ranging is a straight line means fixing a series of pegs or
other marks such that they all lie on a straight line.
▪ Ranging rods are used marking points on the ground so that the
positions of the points are distinctly visible from some distant way.
▪ The length of ranging rod may be 2 m and 3 m and its
diameter is 30 mm.
▪ Ranging rod made of steel tube or made of well seasoned,
straight grained timber of circular cross section.
By :-Denis Jangeed

Ranging Rod
▪ Ranging rods should be straight
and free from wraps.
▪ The deviation in straightness should
not exceed 5 mm in a 2 m length.
▪ The ranging rod is painted in red
and white in alternate band
lengths of 200 mm each.
▪ The bottom end of the rod is fitted
with a pointed, hollow, cast iron
shoe or steel shoe of 15 cm length.
By :-Denis Jangeed

Offset Rod
▪ It is a ranging rod with two short, narrow, vertical sighting
slots passing through the centre of the section.
▪ A hook is fitted of a groove is cut at the top to enable pulling
or pushing of the chain through obstruction like hedges.
▪ Offset rods are meant for setting outlines approximately
at right angles to the main line.
By :-Denis Jangeed

Cross Staff
▪ It is used to set out right angles in chain surveying
▪ It consists of four metal arms vertical slits mounted on
a pole.
▪ Two opposite slits are positioned along the length of a
line (Main Line)
▪ A line perpendicular to the main line is formed or
sighted through the other two slits

Plumb Bob
▪ It consists of a solid conical piece
and a string attached to it at its
centre.
▪ When in use, the solid piece is at
the bottom.
▪ It is used to test the verticality of the
ranging rods and to transfer the
points to the ground.
▪ Plumb bob is used while doing
chain surveying on sloping ground.
By :-Denis Jangeed

(ii) Chaining:-
▪ Chaining method determines the distance by means of a tape or
a chain. This is one of the accurate methods to determine the
linear measurements.
▪ The chain is used for ordinary precision.
▪ Tape is used to measure distance with high precision.
Chains:-
Depending upon the length of the chain, these are divided into
following types
▪ Metric chains
▪ Steel band or Band chain
▪ Gunter’s chain or surveyor’s chain
▪ Revenue chain
▪ Engineer’s chain
By :-Denis Jangeed

Metric chains:-
▪ Metric chains are the most commonly used chain in India.
▪ These types of chains comes in many lengths such as 5, 10, 20 and 30
meters. Most commonly used is 20m chain.
▪ Tallies are provided at every 1m of the chain for quick reading. Every
link of this type of chain is 0.2m. The total length of the chain is
marked on the brass handle at the ends.
▪ As per IS code:1492.1970 for Metric surveying chains
▪ https://law.resource.org/pub/in/bis/S01/is.1492.1970.pdf
By :-Denis Jangeed

Steel band or Band chain:-
▪ These types of chain consist of a long narrow strip of steel
of uniform width of 12 to 16 mm and thickness of 0.3 to
0.6 mm.
▪ This chain is divides by brass studs at every 20cm or
instead of brass studs, band chain may have graduated
engraving as centimetre.
▪ For easy use and workability band chains are wound on
steel crosses or metal reels from which they can be easily
unrolled.
By :-Denis Jangeed

Gunter’s chain or Surveyor’s chain:-
▪ Gunter chain comes in standard 66ft. These chain consists
of 100 links, each link being 0.66ft or 7.92inches. The
length 66ft is selected because it is convenient in land
measurements.
▪ 10 square Gunter’s chains = 1 Acre
▪ 10 Gunter chains = 1 Furlong
▪ 80 Gunter chains = 1 mile=1.6093 KM
By :-Denis Jangeed

Revenue Chain:-
▪ The standard size of this type of chain is 33ft. The number
of links are 16, each link being 2.0625 ft
▪ This chain is commonly used in cadastral survey.
By :-Denis Jangeed

Engineer’s chain:-
▪ This chain comes in 100 ft length.
▪ Its consist of 100 links each link being 1ft long.
▪ Tallies are provided at every 3m (For 30m Chain) of the chain for
quick reading.
▪ At every 10 links a brass ring or tags are provided for indication
of 10 links. Readings are taken in feet and decimal. Used for all
engineering works like- Roads,canals,
▪ Made of galvanised mild steel. Link dia- 4MM.
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Engineer’s chain:- Details
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Tape:-
Tapes are used in surveying for measuring horizontal, vertical
distances. Tapes are issued in various lengths, widths and materials
graduated in a variety of ways.
Following types of tapes available in surveying for linear measurements
and they are as follows :-
▪ Linen/cloth Tape
▪ Metallic Tape
▪ Steel Tape
▪ Invar Tape
By :-Denis Jangeed

Linen/cloth Tape:-
▪ Linen tape, also known as cloth tape is a varnished strip made of
closely woven linen. The width of the strip is about 12 to 15 mm.
▪ It is available in different lengths such as 10m, 20m, 25m, and 30m.
▪ Linen tapes are light in weight and easy to handle as compare to
chain.
▪ These tapes are not suitable for accurate surveying measurements.
▪ These are generally used for measuring offsets and for ordinary
works.
By :-Denis Jangeed

Metallic Tape:-
▪ The metallic tape is an improved version of linen tape. Brass or copper made
wires are used as reinforcement for the linen material.
▪ It is more durable than normal linen tape. A brass ring is provided at the end
of the tape which is included in the length of the tape.
▪ These tapes are available in different lengths of 2m, 5m, 10m, 20m, 30m,
and 50m.
▪ These are used for survey works such as topographical survey works where
minor errors are not taken into consideration.
By :-Denis Jangeed

Steel Tape:-
▪ A steel tape is made of steel or stainless steel & its a very lightweight.
▪ Easy to handle.
▪ It consists of a steel strip of 6mm to 16mm wide.
▪ It is available in lengths of 1m, 2m, 5m, 8m, 10m, 20m, 30m and
50m. Meters, decimetres, and centimetres are graduated in the steel
strip.
By :-Denis Jangeed

Invar Tape:-
▪ Invar tapes are made of an alloy which consists of 36% of nickel and
64% of steel.
▪ Invar tape contains a 6mm wide strip and is available in different
lengths of 30m, 50m, 100m.
▪ The coefficient of thermal expansion of invar alloy is very low.
▪ It is not affected by changes in temperature. Hence, these tapes are
used for high precision works in surveying such as baseline
measurement, triangulation surveys, etc.
▪ Invar tapes are expensive than all the other types of tapes.
▪ These tapes should be handled with care otherwise bends or kinks
(knot) may be formed.
By :-Denis Jangeed

Previous Years Questions & answers of GATE & IES:-
By :-Denis Jangeed

Tape Correction:-
Error =MV-TV
Correction= TV-MV
Error= - Correction
MV=Measured Value,
TV=True Value
Example :-
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Chain or Tape Correction:-
The following corrections provided for chain or tape measurements
while conducting chain or tape surveying are:-
1. Correction for absolute length
2. Correction for pull or tension
3. Correction for temperature
4. Correction for Sag
5. Correction for Slope
6. Correction for Alignment
The correction is
▪ Positive (+ve) if the erroneous length is to be increased or Negative
▪ Negative (-ve) if the erroneous length must be decreased or Positive
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1. Correction for Absolute Length
▪ If Ca is the correction for absolute length or the actual
length, then it is given by:
Where, L = Measured length of the line; c = Correction per
tape length; l= designated length of the tape or the nominal
length.
▪ Different cases are:
1. Absolute length > Designated length means Measured
distance is short, hence the correction is additive.
2. Absolute length < Designated length means, Measured
distance is long, hence the correction is subtractive.
The sign of correction Ca is the same as that of ‘c’.
Ca = L*c/l
By :-Denis Jangeed

2. Correction for Temperature
▪ The correction for temperature Ct is given by the formula:
Where
α = Coefficient of thermal expansion
Tm = the mean temperature in the field during
measurement
To = the temperature during the standardization of the tape
L = Measured length
There are two cases possible:-
1. Tm > To
Hence the correction is additive.
2. Tm<To
Hence the correction is subtractive.
Ct = α (Tm –To) L
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3. Correction for Pull or Tension
The correction for pull or tension is given by the formula:-
Where,
P = Pull applied during the measurement (N)
Po= Standard Pull (N)
L = measured length (m)
A =Area of cross-section in (cm2)
E = Young’s modulus in (N/cm2)
Two cases are possible:-
1. if P > Po, then correction is (+ve)
2. if P < Po, then correction is (-ve)
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4. Correction for Sag:-
▪ Stretching the tape between two supports make the tape to
form a horizontal catenary. Hence, the horizontal distance
becomes greater than the distance along the curve.
▪ Sag Correction = (Horizontal distance – length along the
horizontal catenary)
▪ Tape correction per length is given by,
Where,
Cs = Tape Correction per Tape length
l=Total length of the tape
W= total weight of the tape
n= number of equal spans
P= Pull applied
Cs = lW2 /24n2P2
By :-Denis Jangeed

5. Correction for Slope or Vertical Alignment
The slope correction or correction due to vertical alignment is
given by the relation:
Or
Where,
h = The difference in elevation between the ends;
x = slope measured
The distance that is measured along the slope is always greater
than the horizontal distance. This makes the correction to be
subtractive.
Cv = 2L sin2(x/2) b
L
h
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6. Correction for Horizontal Alignment
▪ Stretching the tape out of line results in greater distance value. The
correction is therefore negative.
▪ AB is the measured length and AC is the correct alignment. Hence, the
correction is given by:
Ch = d2/2L
L
l
d
B1
A B
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Ranging of Survey line:-
▪ While measuring the survey lines,
the chain or the tape has to be
stretched along the survey line along
that joins two terminal stations.
▪ When the line to be measured has a
smaller length compared to the chain,
then the measurement goes smooth.
If the length of the line is greater, the
survey lines have to be divided by
certain intermediate points, before
conducting the
chaining process. This process is
called ranging.
By :-Denis Jangeed

The process of ranging can be done by two methods:-
1. Direct Ranging
2. Indirect Ranging
1. Direct Ranging:-
▪ Direct ranging is the ranging conducted when the intermediate
points are intervisible.
▪ Direct ranging can be performed by eye or with the help of an
eye instrument.
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Ranging by Eye:-
▪ let A and B are the two intervisible points at the ends of the
survey line.
▪ The surveyor stands with a ranging rod at the point A by
keeping the ranging rod at the point B. The ranging rod is held
at about half metre length. The assistant then takes the ranging
rod and establishes at a point in between AB, almost in line
with AB. This is fixed at a distance not greater than one chain
length from point A.
▪ The surveyor can give signals to the assistant to move traverse
till the rod is in line with A and B. In this way, other
intermediate points are determined.
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Ranging by Line Ranger
▪ A line ranger that has either two plane mirror arrangement or two isosceles
prisms that are placed one over the other. The diagonals of the prism are
arranged and silvered such that they reflect incident rays.
▪ In order to handle the instrument in hand a handle with hook is provided.
The hook is to enable a plumb - bob to help transfer the point to the
ground. In order to range the point ‘P’, initially two rods are fixed at points
A and B. By eye judgment, the surveyor holds the ranging rod at P almost
in line with AB.
▪ The lower prism abc receives the rays coming from A which is then
reflected by the diagonal ac towards the observer. The upper prism dbc
receives the rays from B which is then reflected by the diagonal bd
towards the observer. Hence the observer can see the images of the
ranging rods A and B, which might not be in the same vertical line.
▪ The surveyor moves the instrument till the two images come in the same
vertical line .With the help of a plumb bob, the point P is then transferred
to the ground. This instrument can be used to locate the intermediate
points without going to the other end of the survey line. This method only
requires one person to hold the line ranger.
By :-Denis Jangeed

Fig: Line Ranger
By :-Denis Jangeed

2. Indirect Ranging
▪ Indirect ranging is employed when the two points are not intervisible
or the two points are at a long distance. This may be due to some
kind of intervention between the two points.
▪ In this case, the following procedure is followed:-
⮚ Two intermediate points are located M1 and N1 very near to
chain line by judgment such that from M1, both N1 and B
are visible & from N1 both M1 and A are visible.
⮚ At M1 and N1 two surveyors stay with ranging rods. The
person standing at M1 directs the person at N1 to move to a
new position N2 as shown in the figure. N2 must be inline
with M1B.
⮚ Next, a person at N2 directs the person at M1 to move to a
position M2 such that it is inline with N2A. Hence, the two
persons are in points are M2 and N2.
⮚ The process is repeated until the points M and N are in the
survey line AB. Finally, it reaches a situation where the
person standing at M finds the person standing at N in line
with NA and vice versa. Once M and N are fixed, other
points are fixed by direct ranging.
By :-Denis Jangeed

Reciprocal (Indirect Ranging)
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Instrument used for measurement of Direction and Angle:-
(a) Direction
1. Surveyor Compass
2. Prismatic Compass
(b) Angle
1. Sextant
2. Theodolite
Bearing and Angle:-
Bearing:-
• Bearing of a line is its direction relative to a given meridian. or
• The bearing of a line is the horizontal angle which it makes with a reference line
(meridian) depending upon the meridian, there are four types of bearings.
Angle:- It is difference in direction between to intersection lines.
Designation of bearing:-
The common system of notation of bearing
1. Whole circle bearing (WCB)
2. Reduced Bearing (RB) or Quadrantal Bearing (QB)
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1. Whole circle bearing (WCB):-
▪ Bearings measured from north in a clockwise direction is
termed as whole circle bearing.
▪ The value varies from 0 degrees to 360 degrees.
▪ Ex.- Prismatic compass
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2. Reduced Bearing (RB) or Quadrantal Bearing (QB)
▪ The bearings measured either from the north or from the
south towards east or west whichever is nearer is known as
reduced bearing.
▪ The values vary from 0 degrees to 90 degrees for a
particular quadrant.
▪ It is also known as Quadrantal bearing (QB).
▪ Ex.- Surveyor compass
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Conversion of bearing from one system to other system:-
(a) W.C.B to Q.B (R.B)
Line W.C.B
(Degree)
R.B Quadrant
AB 0 & 90 R.B = W.C.B NE
AC 90 & 180 R.B = 180- W.C.B SE
AD 180 &
270
R.B = W.C.B – 180 SW
AF 270 &
360
R.B = 360- W.C.B NW
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(b) Q.B (R.B) to W.C.B
Line R.B W.C.B W.C.B
Between
AB Nø1E W.C.B= R.B 0 & 90
AC Sø2E W.C.B= 180-
R.B
90 & 180
AD Sø3W W.C.B=
180+ R.B
180 & 270
AF Nø4W W.C.B= 360-
R.B
270 & 360
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Bearing:- The bearing of a line is the horizontal angle which it makes
with a reference line (meridian) depending upon the meridian, there are
four types of bearings.
Meridian:-Meridians are imaginary lines of longitude on the earth
that extend from the North to South Pole. A principal meridian is
one which is used as a reference line to survey a large area. There are
four types of meridians.
By :-Denis Jangeed
Types of Meridian:- Types of Bearing:-
True Meridian (TM) True Bearing (TB)
Magnetic Meridian (MM) Magnetic Bearing (MB)
Grid Meridian (GM) Grid Bearing (GB)
Arbitrary Meridian (AM) Arbitrary Bearing (AB)

1. True meridian:-
▪ True meridian through a point is the line in which a plane, thus
passes through the true north and south poles, intersects with the
surface of the earth. It thus passes through the true north and
south.
▪ The direction of the true meridian through a point can be
established by astronomical observations.
▪ It is also known as Azimuth
True Bearing:
▪ True bearing of a line is the horizontal angle which it makes with
the true meridian through one of the extremities of the line.
▪ The direction of the true meridian through a point remains fixed,
the true bearing of a line is a constant quantity.
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2. Magnetic Meridian:-
▪ The magnetic bearing through a point is the direction shown
by a freely floating and balanced magnetic needle free from
all other attractive forces.
▪ The direction of magnetic meridian can be established with
the help of a magnetic compass.
Magnetic bearing:-
▪ The magnetic bearing of a line is the horizontal angle which
it makes with the magnetic meridian passing through one of
the extremities of the line.
▪ A magnetic compass is used to measure it.
By :-Denis Jangeed

3. Grid meridian
▪ For survey of a country, the true meridian passing
through the central place is sometimes taken as a
reference meridian for the whole country. Such a
reference meridian is known as grid meridian. The
meridians of all other places in that state are assumed to be
parallel to the grid meridian
Grid bearing:
▪ The grid bearing of a line is the horizontal angle which the
line makes with the grid meridian.
By :-Denis Jangeed

4. Arbitrary meridian
▪ Arbitrary meridian is any convenient direction towards a
permanent and prominent mark or signals, such as a church
spire or top of a chimney.
▪ Such meridians are used to determine the relative positions
of lines in a small area
Arbitrary bearing:
▪ Arbitrary bearing of a line is the horizontal angle which it
makes with any arbitrary meridian passing through one of
the extremities.
▪ A theodolite or sextant is used to measure it.
By :-Denis Jangeed

Fore bearing and Back bearing:-
▪ Fore bearing
The bearing of a line measured in the forward direction of
the survey lines is called the 'fore bearing'(F.B.) of that line.
▪ Back bearing
The bearing of a line measured in direction backward to the
direction of the progress of survey is called the 'back
bearing'(B.B.) of the line.
▪ Relation between F.B. And B.B.
+ve if F.B < 180º
-ve if F.B > 180º
B.B = F.B ± 180
By :-Denis Jangeed

By :-Denis Jangeed
Examples
▪ Convert the following WCB into Reduced Bearing.
• 49°
• 240°
• 133°
• 335°

By :-Denis Jangeed
Examples
▪ Convert the following WCB into RB.
• 190°
• 260°
• 315°

By :-Denis Jangeed
Examples
▪ Convert the following reduced bearings into whole circle
bearings
▪ N 65° E
▪ S 43° 15′ E
▪ S 52° 30′W
▪ N 32° 42′W

By :-Denis Jangeed
Compass Surveying: -
▪ Chain surveying can be used when the area to be surveyed is
comparatively small and is fairly flat.
▪ But when the area is large, undulated and crowded with many
details, triangulation (which is the principle of chain survey) is not
possible. In such an area, the method of traversing is adopted.
Traversing :-
▪ Traversing is that type of survey in which a number of
connected survey lines form the framework and the directions and
lengths of the survey lines are measured with the help of an angle
measuring instrument and tape or chain respectively. This process
is known as Compass Traversing.

Types of traverse surveying.
They are two types:-
1. Closed traverse:-
When the lines form a circuit which ends at the starting point, it is
known as a closed traverse. Like -Pond
2. Open traverse:-
When the lines form a circuit ends elsewhere except starting
point, it is said to be an open traverse. Like village street to
highway then international highway.
By :-Denis Jangeed

Principle of Compass Surveying
• The Principle of Compass Survey is Traversing; which involves
a series of connected lines the magnetic bearing of the lines are
measured by prismatic compass and the distance (lengths) of the
are measured by chain. Such survey does not require the
formulation of a network of triangle.
• Compass surveying is recommended when the area is large,
undulating and crowded with many details.
• Compass surveying is not recommended for areas where local
attraction is suspected due to the presence of magnetic
substances like steel structures, iron ore deposits, electric cables
conveying currents, and so on.
By :-Denis Jangeed

Methods of Traversing
There are several methods of traversing, depending on the
instruments used in determining the relative directions of the
traverse lines.
The following are the principal methods:-
1. Chain traversing
2. Chain and compass traversing
3. Transit type traversing
a) By fast needle method
b) By measurement of angles between the lines
4. Plane table traversing
By :-Denis Jangeed

1. Chain Traversing
▪ The method in which the whole work is done with chain and
tape is called chain traversing.
▪ No angle measurement is used and the directions of the lines
are fixed entirely by linear measurements Angles fixed by
linear or tie measurements are known as chain angles.
▪ The method is unsuitable for accurate work and is generally
used if an angle measuring instruments such as a compass,
sextant or theodolite is available.
By :-Denis Jangeed

2. Chain and Compass Traversing
▪ In chain and compass traversing, the magnetic bearings of the
survey lines are measured by a compass and the lengths of the
lines are measured either with a chain or with a tape.
▪ The direction of the magnetic meridian is established at each
traverse station independently.
▪ The method is also known as a tree or loose needle method.
3. Transit type traversing
(a) Traversing by Fast Needle Method
▪ The method in which the magnetic bearings of traverse lines
are measured by a theodolite fitted with s compass is called
traversing by fast needle method.
▪ The direction of the magnetic meridian is not established at
each station but instead, the magnetic bearings of the lines are
measured with a reference so that direction of the magnetic
meridian established at the first station.
By :-Denis Jangeed

▪ There are three methods of observing the bearings of lines
by fast needle method.
1. Direct method with transiting,
2. Direct method without transiting,
3. Back bearing method.
By :-Denis Jangeed

Traversing By Direct Observation Of Angles
▪ In this method, the angles between the lines are directly
measured by a theodolite and the magnetic bearing of other
lines can be calculated in this method. The angles measured
at different stations may be either
1. Included Angles
2. Deflection Angles
1. Traversing by Included Angle
▪ An included angle at a station is either of the two angles
formed by two survey lines meeting there and these angles
should be measured clockwise.
▪ The method consists simply in measuring each angle
directly from a back sight on the preceding station. The
angled may also be measured by repetition.
▪ The angles measured from the back station may be interior
or exterior depending on the direction of progress.
By :-Denis Jangeed

If (a) The direction of progress is counter-clockwise and so the
angles measured clockwise are the interior angle.
(b) The direction of progress is clockwise and so the angles
measured clockwise are the exterior angle.
By :-Denis Jangeed

Traverse by Deflection Angles
▪ A deflection angle is an angle in which a survey line makes
with the prolongation of the preceding line.
▪ It is designated as right (R) or left (L) as it is measured
clockwise or anti-clockwise from the prolongation of the
previous line.
▪ This type of traversing is more suitable for the survey of
roads, railways, pipe-lines, etc where the survey lines make
small deflection angles.
By :-Denis Jangeed

Compass, Uses & Types of Compass: -
▪ Compass: A compass is a small instrument essentially Consisting
of magnetic needle, a graduated circle, and a line of sight. The
compass can not measure angle between two lines directly but can
measure angle of a line with reference to magnetic meridian at the
instrument station point is called magnetic bearing of a line. The
angle between two lines is then calculated by getting bearing of
these two lines.
▪ There are two forms of compass available:
1. Prismatic Compass
2. Surveyor’s Compass

Prismatic Compass: -
▪ A prismatic compass is one of the most convenient and portable
forms of the magnetic compass.
▪ It can be held in hand or in a tripod stand for carrying out the
measurement.
▪ The line of sight is defined by the object vane and the eye vane.

Prismatic Compass cont…: -
▪ A prismatic compass helps to conduct both sightings and reading
simultaneously.
▪ The compass is initially held over the starting station of the survey
line and the adjustments are provided. The magnetic meridian is
thus obtained and then starts to take the measurements by sighting
to the next station.
▪ The readings increase in clockwise direction i.e. from the 0˚ to
360˚
By :-Denis Jangeed

Following instruments are required for conducting a prismatic
compass survey
i ). Prismatic compass with tripod stand
ii). Measuring Tape
iii ). Arrows
iv). Ranging Rods
v ). Plumbing Fork or Plumb Bob
vi ). Field Book
Parts of Prismatic Compass and Their Functions:-
Cylindrical Metal Box:- Diameter of 8cm to 12cm. Protect the compass.
Forms entire casing or body of the compass.
Pivot: - Centre of the compass. Supports the magnetic needle over it.
Brake or Brake Pin :- To damp the oscillation of the needle. To bring it
to rest quickly.
Magnetic Needle: - Heart of the instrument. Measures angle of a line.
Always pointed to North and South pole.
By :-Denis Jangeed

Graduated Circle or Ring: - Aluminium graduated circle marked with
0˚ and 360˚ to measure all possible bearings of lines. The ring is
graduated to half a degree.
Prism: - Read graduations on ring and to take exact reading by
compass. Placed exactly opposite to object vane. The prism hole is
protected by prism cap to protect it from dust and moisture.
Object Vane: - Diametrically opposite to the prism and eye vane.
Carrying horse hair or black thin wire to sight object in line.
Eye Vane: - A fine slit provided with eye hole at bottom to bisect the
object from the slit. Take reading simultaneously from the eye
hole. Provided with prism and can be lifted up and down by the
stud to bisect the object of higher level.
Sunglasses: - Used when some luminous objects are to be bisected.
Placed in front of the eye slit and in bunch of 3 or 4 shades of
different colours to give sharp picture of the objects only.
By :-Denis Jangeed

Surveyor Compass: -
▪ It is similar to a prismatic compass
except that it has only plain eye slit
instead of eye slit with prism and eye
hole.
▪ This compass is having pointed
magnetic needle in place of broad form
needle as in case of prismatic compass.
By :-Denis Jangeed

Temporary Adjustments for Prismatic Compass
The temporary adjustments usually followed for prismatic compass
are:
1. Centering
2. Levelling
3. Focusing the Prism
1. Centering:
In this step, the instrument is kept exactly over the station point.
This can be done either by adjusting the tripod stands or by using a
plumb-bob. Sometimes, a pebble can be freely dropped from this
center to the bottom of the instrument to check the centering.
By :-Denis Jangeed

2. Levelling:
The instrument must be held such that the graduated disc swings
freely and when viewed from the top edge it must appear level. If
it is not used as a hand instrument, a tripod is used to support the
instrument for levelling.
3. Focusing the Prism:
Till the readings are observed sharp and clear, the prism
attachment is slid up and down for proper focusing.
By :-Denis Jangeed

Theodolite:-
▪ A Theodolite is a measuring instrument used to measure the
horizontal and vertical angles.
▪ The system of surveying in which the angles are measured with
the help of a theodolite, is called Theodolite surveying.
▪ Theodolite is more precise than magnetic compass.
▪ Magnetic compass measures the
angle up to as accuracy of 30'.
a vernier theodolite measures the
angles up to and accuracy of 10", 20".
▪ It is of either transit or non-transit
type.
By :-Denis Jangeed

Fundamental axis of theodolite and their relationship:-
By :-Denis Jangeed

Uses of Theodolite:-
Measuring horizontal and vertical angles.
▪ Locating points on a line.
▪ Prolonging survey lines.
▪ Finding difference of level.
▪ Setting out grades
▪ Ranging curves
▪ Tacheometric Survey
Classification of Theodolite:-
1. Transit Theodolite:-
A theodolite is called a transit theodolite when its telescope can be
transited i.e. revolved through a complete revolution about its horizontal
axis in the vertical plane.
2. Non-Transit:-
The telescope cannot be transited. They are inferior in utility and have
now become obsolete.
By :-Denis Jangeed

3. Vernier Theodolite:-
▪ For reading the graduated circle if verniers are used ,the
theodolite is called as a Vernier Theodolite.
4. Micrometer Theodolite:-
▪ Whereas, if a micrometer is provided to read the graduated circle
the same is called as a Micrometer Theodolite.
Note:- Vernier type theodolites are commonly used .
Size of Theodolite:-
▪ A theodolite is designated by diameter of the graduated circle on the
lower plate.
▪ The common sizes are 8 cm to 12 cm while 14 cm to 25cm 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.
By :-Denis Jangeed

Terms used in manipulating a transit vernier theodolite:-
1. 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.
2. 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.
3. Swinging the telescope:-
It means turning the telescope about its vertical axis in the
horizontal plane. A swing is called right or left according as
the telescope is rotated clockwise or counter clockwise.
By :-Denis Jangeed

4. 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 and the
observation taken on the horizontal or vertical circle in this position, is
known as the face left observation.
5. 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
and the observation taken on the horizontal or vertical circle in this
position, is known as the face right observation.
6. Changing Face:-
▪ It is the operation of bringing the vertical circle to the right of the
observer ,if originally it is to the left , and vice – versa.
▪ It is done in two steps; Firstly revolve the telescope through 180° in a
vertical plane and then rotate it through 180° in the horizontal plane
i.e. first transit the telescope and then swing it through 180°.
By :-Denis Jangeed

7. Line of Collimation:-
▪ It is also known as the line of sight (LOS).
▪ 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.
8. Axis of the telescope:-
▪ It is also known an imaginary line joining the optical centre of the
object- glass to the centre of eye piece.
By :-Denis Jangeed

10. Vertical Axis:-
It is the axis about which the telescope can be rotated in the
horizontal plane.
11. Horizontal (trunnion) Axis:-
It is the axis about which the telescope can be rotated in the vertical
plane. It is also called the trunnion axis.
By :-Denis Jangeed

Temporary adjustment of theodolite:-
Following three steps are used
1. Setting up
2. levelling up
3. Elimination of parallax
(1). Setting up:-
▪ The initial setting operation includes fixing the theodolite on
a tripod, along with approximate levelling and centering over the
station mark.
▪ For setting up the instrument, the tripod is placed over the station
with its legs widely spread so that the centre of the tripod head
lies above the station point and its head approximately level (by
eye estimation).
▪ The instrument is then fixed with the tripod by screwing through
the trivet.
▪ Centering means bringing the vertical axis of the theodolite
exactly over the station mark.
By :-Denis Jangeed

(2). Levelling up:-
▪ Levelling of an instrument is done to make it vertical axis
with respect to the apparent force of gravity at the
station.
Following are steps for instrument levelling:-
• Bring one of the level tubes parallel to any two of the foot screws,
by rotating the upper part of the instrument.
• The bubble is brought to the centre of the level tube by rotating
both the foot screws either inward or outward. The bubble moves
in the same direction as the left thumb.
• The bubble of the other level tube is then brought to the centre of
the level tube by rotating the third foot screw either inward or
outward. [In step 1 itself, the other plate level will be parallel to the
line joining the third foot screw and the centre of the line joining
the previous two foot screws.
By :-Denis Jangeed

• Repeat step 2 and step 3 in the same quadrant till both the
bubble remain central.
• By rotating the upper part of the instrument through 180°, the
level tube is brought parallel to first two-foot screws in reverse
order. The bubble will remain in the centre if the instrument is
in permanent adjustment. Otherwise, repeat the whole process
starting from step 1 to step 5.
Three foot screw levelling head
By :-Denis Jangeed

(3). Elimination of Parallax:-
Parallax can be eliminated is two steps.
a) By focusing the eye-piece for distinct vision of the cross –
hairs.
b) By focusing the objective to bring the image of the object in the
plane of cross-hairs.
(a). Focusing of eyepiece:-
▪ For focusing of the eye piece, point the telescope to the sky
or hold a piece of white paper in front of telescope.
▪ Move the eye-piece in and out until a distinct sharp black
image of the cross-hairs is seen.
(b). Focusing of objective lens:-
▪ It is done for each independent observation to bring the
image of the object in the plane of cross hairs.
By :-Denis Jangeed

▪ It includes following steps of operation:- First, direct
the telescope towards the object for observation. Next, turn the
focusing screw until the image of the object appears clear and sharp
as the observer looks through properly focused eye-piece. If
focusing has been done properly, there will be no parallax.
MEASUREMENT OF HORIZONTAL ANGLES:-
There are three methods of measuring horizontal angles:-
a) Ordinary Method.
b) Repetition Method.
c) Reiteration Method.
By :-Denis Jangeed

a) Ordinary Method:-
To measure horizontal angle AOB:-
i) Set up the theodolite at station point O and level it accurately.
ii) Set the vernier A to the zero or 360° of the horizontal circle.
Tighten the upper clamp.
iii) Loosen the lower clamp. Turn the instrument and direct
the telescope towards A to bisect it accurately with the use of
tangent screw. After bisecting accurately check the reading
which must still read zero. Read the vernier B and record
both the readings.
iv) Loosen the upper clamp and turn the telescope clockwise
until line of sight bisects point B on the right hand side.
Then tighten the upper clamp and bisect it accurately by
turning its tangent screw.
By :-Denis Jangeed

v) Read both verniers. The reading of the vernier a which was initially
set at zero gives the value of the angle AOB directly and that of the
other vernier B by deducting 180°. The mean of the two vernier
readings gives the value of the required angle AOB.
vi) Change the face of the instrument and repeat the whole process.
The mean of the two vernier readings gives the second value of the
angle AOB which should be approximately or exactly equal to the
previous value.
vii) The mean of the two values of the angle AOB ,one with face left
and the other with face right ,gives the required angle free from all
instrumental errors.
By :-Denis Jangeed

b) Repetition Method:-
▪ This method is used for very accurate work.
▪ In this method ,the same angle is added several times
mechanically and the correct value of the angle is obtained by
dividing the accumulated reading by the no. of repetitions.
▪ The No. of repetitions made usually in this method is six, three
with the face left and three with the face right .
▪ In this way ,angles can be measured to a finer degree of
accuracy than that obtainable with the least count of the vernier.
To measure horizontal angle by repetitions:-
i) Set up the theodolite at starting point O and level it accurately.
ii) Measure The horizontal angle AOB.
iii) Loosen the lower clamp and turn the telescope clockwise until the
object (A) is sighted again. Bisect B accurately by using the upper
tangent screw. The verniers will now read the twice the value of the
angle now
By :-Denis Jangeed

iv) Repeat the process until the angle is repeated the required number
of times (usually 3). Read again both verniers . The final reading
after n repetitions should be approximately n X (angle). Divide the
sum by the number of repetitions and the result thus obtained gives
the correct value of the angle AOB.
v) Change the face of the instrument. Repeat exactly in the same
manner and find another value of the angle AOB. The average of
two readings gives the required precise value of the angle AOB.
By :-Denis Jangeed
X+2X+3X
Final Reading =
3
Let the reading

iii) Reiteration Method:-
This method is another precise and comparatively less tedious
method of measuring the horizontal angles. It is generally preferred
when several angles are to be measured at a particular station. This
method consists in measuring several angles successively and
finally closing the horizon at the starting point. The final reading of
the vernier A should be same as its initial reading.
Procedure
Suppose it is required to measure the angles AOB, BOC and COD.
Then to measure these angles by repetition method :-
i) Set up the instrument over station point O and level it
accurately.
By :-Denis Jangeed

ii) Direct the telescope towards point A which is known as referring
object. Bisect it accurately and check the reading of vernier as 0 or
360° . Loosen the lower clamp and turn the telescope clockwise to
sight point B exactly. Read the verniers again and The mean reading
will give the value of angle AOB.
iii) Similarly bisect C & D successively, read both verniers at
each bisection, find the value of the angle BOC and COD.
iv) Finally close the horizon by sighting towards the referring object
(point A).
v) The vernier A should now read 360° . If not note down the error
.This error occurs due to slip etc.
vi) If the error is small, it is equally distributed among the several
angles .If large the readings should be discarded and a new set of
readings be taken.
By :-Denis Jangeed

By :-Denis Jangeed
It should be 360°

Definition and Terms used in levelling:-
1. (BS- Back sight)
▪ It is the first staff reading taken by the surveyor after the
levelling instrument is set up and levelled.
▪ B.S is generally taken on the point of known (Elevation point)
reduced level as on the benchmark or a change point.
2. (FS- Fore sight)
▪ It is the last staff reading taken before changing the instrument
to the other position.
▪ It is the staff reading taken on point whose RL is to determined.
▪ This sight is considered as negative and deduced from Height of
Instrument to determine RL of the point.
By :-Denis Jangeed

5. (IS- Intermediate sight)
▪ All readings taken between backsight and foresight.
▪ These are the points whose RL is determined by the method
already mentioned above in FS.
▪ Also called inter-sight readings.
4. (RL- Reduced Level)
▪ It is the height or depth of any survey points with reference to a
given assumed datum.
▪ The elevation is positive or negative according as point lies
above or below datum.
5. (B.M- BenchMark)
▪ Fixed reference point of known elevation with respect to which
RL of other points is determined.
By :-Denis Jangeed

▪ Benchmarks can be arbitrary or permanent, the former is used
for calculation of reduced levels for small survey works and the
latter is used to calculate the elevations of significantly
important locations and points.
▪ Arbitrary benchmarks are assumed to be equal to 100 meters
generally and then the elevations with respect to assumed
benchmark is determined. It is commonly practiced by
engineering students.
▪ For GTS surveys of the country, surveyors use permanent
benchmarks to calculate the elevations of different points.
6. Datum Surface:-
▪ It is Reference plane with respect to which RL of the other
survey points is determined.
▪ The datum surface may be real or imaginary location with a
nominated elevation of zero.
▪ The commonly used datum is mean sea level.
By :-Denis Jangeed

7. Levelling Staff:-
▪ A level staff, also called levelling rod, is a graduated wooden or
aluminium rod, used with a levelling instrument to determine the
difference in height between points or heights of points above a
vertical datum.
▪ It cannot be used without a levelling instrument.
8. (HI- Height of instrument)-
The height of the line of sight of a levelling instrument above the
adopted datum
By :-Denis Jangeed

Bench Mark(B.M)
▪ It is a fixed reference point whose elevation with respect to some
datum is known.
▪ It is noted that any levelling work is first started from BM.
Types of Bench Mark
(a) GTS benchmark
(b) Permanent benchmark
(c) Arbitrary benchmark
(d) Temporary benchmark
(a) GTS benchmark (Great trigonometrical survey benchmark)-
▪ This benchmark is established by the survey of India department at
a large interval all over the country.
▪ The values of reduced level the relevant position and the number of
the benchmark are given in a catalogue published by this
department.
By :-Denis Jangeed

(b) Permanent benchmark-
▪ This is a fixed point or mark established by different government
department like PWD railway, irrigation etc.
▪ The RLs of this point is determined with reference to the GTS
benchmark and are kept on permanent point like the plinth of a
building, parapet of a bridge or culvert and so on.
(c) Arbitrary benchmark-
▪ when small ordinary levelling work is to be carried out or when the
permanent benchmark is not nearby the place where the survey is to
be carried out then to start the levelling work any prominent object
like plinth or step of building etc. is chosen as the benchmark and its
elevation is assumed arbitrarily.
By :-Denis Jangeed

Surveying Complete Notes of Unit 1.pptx

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