1.

Surveying
1. General
Surveying is the art of determining the relative positions of distinctive features on the
surface of the earth or beneath the surface of the earth, with the help of distance, directions and
elevations. The main objective of surveying is preparation of maps & plans showing the
relative position of existing features by which areas, volumes and other related quantities are
determined.
 *Topographic survey is done to locate the natural features of the country/continent/earth
surface.
 *Cadastral survey is done to fix the property line of personal, municipalities, state, in
urban area etc.
 City survey is done for construction of streets, w/s system, sewers etc.
 *Hydrographic survey deals with the bodies of navigation, water supply etc.
 *Astronomical survey deals with the determination of absolute location and absolute
direction of heavenly bodies like sun, moon etc.
 *Cross staff survey is used to locate the boundaries of a field and to determine its area.
The instruments used in cross staff survey are chain, tape, arrows, and cross staff.
 *Geological survey is done to find the layer of crust below the earth surface.
 Ariel survey is types of survey in which air plane/helicopter or any other air media is used
to dram top view.
 Photometry survey is a technique of astronomy concerned with measuring of flux or
intensity of astronomical objects electromagnetic radiation (EMR).
 GPS survey is the latest technique of surveying. The main feature of GPS survey are
following:-
i) Three dimension
ii) Site intervisibility not needed
iii) Day or night operation
iv) High precision
v) Weather independemt* etc.
1.1. Classification
A) Based on Curvature of Earth
a) *Plane Survey:- The survey in which the curvature of the earth is ignored is called plane
survey. If the survey area is less than 260 km2 then survey is considered as plane survey.
b) *Geodetic Survey:- The survey in which the curvature of the earth is considered is called
geodetic survey. If the survey area is more than 260 km2 then survey is considered as
geodetic survey.
 The differences in length between the arc and the subtended chord on the earth surface for
a distance of 18.5km is 10 cm.
 *The difference between the sum of angles of a spherical triangle having an area of
200km2 on the earth surface and that of corresponding angles of the plane triangle is only
1 second. It is also known as spherical excess.
B) Based on Nature of the Field
a) Land Survey:-The survey which is carried out on the earth (no water bodies) is called land
survey. Land survey is further classified into topographic, cadastral and city surveys.
Topographic surveysare used to indicate the natural features such as mountain, river, forest
etc. while cadastral survey is used for demarcate the property lines and city surveys are
carried out for the construction of roads, parks, water supply, sewer etc.
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b) *Hydrographic Survey:- The survey which is carried out for the studies of large water
bodies i.e. physical features present under water, is called hydrographic survey. It is also
known as bathymetric surveying. It is the science of measuring all factors beneath water
that affect all the marine activities like dredging, marine constructions, offshore drilling
etc.
c) *Astronomical Survey:- The survey which is carried out for determining absolute locations
and the direction of any line on the surface of the earth by making observation to heavenly
bodies is called astronomical surveys. Astronomy is the study of everything in the universe
beyond Earth's atmosphere. That includes objects we can see with our naked eyes, like the
Sun, the Moon, the planets, and the stars.
C) Based on Purpose of the Survey
1. *Engineering Survey 2. Military Survey
3. Mine Survey 4. Geological Survey
5. Archeological surveys (Ancient culture)
D) Based on Instruments Used
1. Chain survey 2. Compass survey
3. Plane table survey 4. Theodolite survey
5. Tacheometric survey 6. Triangulation survey
7. Ariel survey 8. Photogrametric survey
1.2. *Principle of Surveying
1. Working from whole to part (The main objective of whole to part is to prevent the
accumulation of errors and to localize minor errors within the frame of centered
point).
2. Location of a point by measurement from two control points.
1.3. Selection of Suitable Method
It depends upon the types of area to be served. It also considers the effect of magnetic field
due to electric current. For example, chain survey is used for the small area having fairly level
ground and compass survey is used where there is no effect of electric field. Plane table
survey is used for the area having open ground. Tacheometric survey is for broken ground.
Angle:- It is defined as the difference in directions of two intersecting lines. The unit of plane
angle is radian. Radian is defined as the measure of the angle between two radii of a circle
which contain an arc equal to the radius of the circle.

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1.4. Scales, Plan & Maps
*Scale is defined as the fixed proportion where every distance between locations of the
points on the map should be equal to their corresponding distances between their positions on
the ground. There are four types of scale:-
a) Plain scale (to measure two dimensions)
b) Diagonal scale (to measure three dimensions)
c) Scale of chords:- It is used to measure or set off angles.
d) Vernier scale:- There are two types of vernier scale:-
1. Direct vernier:- The verniers, which extend in the same direction in which the
graduation of their main scale increases and smallest division is shorter than the
smallest division of their main scale, are called as direct vernier.
2. *Retrograde vernier:- The verniers, which extend in the opposite direction of their
main scale increases and smallest division is longer than the smallest division of their
main scales, are called as retrograde vernier.

Least count (LC):- The difference between smallest division of main scale & vernier scale is
called least count. It is obtained by dividing the value of one division of primary scale by the
total number of divisions of the vernier scale.
If S is the one division of primary scale and n is the total number of divisions of vernier scale;
then
S
Least count =
n
*Representative fraction:- When a scale is expressed as fraction having numerator and
denominator in same unit and keeping the numerator as unity (one), then it is called as
representative fraction.
*Shrinkage factor:- The ratio of shrunk length and actual length of a drawing, is known as
shrinkage factor. It is also known as shrinkage ratio.
Shrunk length
Shrinkage ratio =
Actual length
 *Scale; Large, 1cm=10m
Medium, 1cm=100m
Small, 1cm=1000m
 Plan is defined as a projection of the feature on or near the earth's surface on a horizontal
plane on which horizontal distance and direction are shown on plan while It is drawn on
large scale.
 If the scale of the graphical projection on a horizontal plane is small, then the plan is
termed as map and vertical distances are also represented by contour lines on map.
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 Only horizontal distance and direction are shown on plan while vertical distances are also
represented by contour lines/hatch on map.
# Types of Map
a) Guide map – The map provided for tourist.
b) *Geographical map- Map prepared on small scale.
c) *Topographical map- It has larger scale than geographical map (Natural feature).
d) *Cadastral map- It has larger scale than topographical map (property line).
1.5. Entry into survey field books and level books
In case of survey field book (chain survey) entry data is started from bottom page of field
book to top in upward direction while in the case of the level book entry data is started from top
to bottom in downward direction.
2. Linear Measurements
There are two methods of determining the distances between two points on the
surface of earth:-
a) Direct method:- In this method, distances are actually measured by means of
chain, tape etc.
b) Indirect/ computative method:- In this method, distances are not measured
directly like direct method but computed by observation taken through telescope or
different types of EDM sophisticated instrument. Distpmat, tellurometer etc.
2.1. Tape
a) Cloth or linen tape:- It is made of closely woven linen and varnished to resist moisture. It
is generally used for making offset measurements and rarely used for making accurate
measurement.
b) Metallic tape:- A linen tape reinforced with brass or copper wires to prevent stretching or
twisting of fibers is called metallic tape. The measurement done by metallic tape is more
accurate than linen tape.
c) *Steel tape:- The measurement done by steel tape is more accurate than metallic tape
d) *Invar tape (steel 64% & nickel 36%):- This tape is used where high degree of precision
required.
e) Glass fibre tape:- These tapes do not stretch or shrink due to changes in temperature or
moisture. So this is used in any weather.
 Steel bands are used where high accuracy is required.
2.2. Chain
S.No. Types of chain Length Links
1 *Engineer's chain 100ft Divided into 100 links
2 *Gunter chain 66ft Divided into 100 links
3 *Metric chain 20m Divided into 100 links
" 30m Divided into 150 links
4 *Revenue chain 33ft Divided into 16 links
 *The handle of chain is made of brass and is included in whole length of the chain.
 The length is indicated by brass ring at interval of every one meter and tallies at every 5m,
10m etc. are marked with letter M to distinguish the metric chain with non metric chain.
 The handles have swivel joint to provide flexibility.
 The links are composed of pieces of galvanized mild steel wire 4mm in diameter. The ends
of each link are bent into loops and connected together by means of three oval shaped
rings which afford flexibility to the chain. When a tension of 8 kg weight is applied at the
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 ends of a chain and compared with a steel band standardized, accuracy must  2mm per
metre length and  5mm &  8mm for overall length of the chain having length 20m & 30
m respectively. Each links are connected by three circular ring having 13 mm dia. Length
of one link is 20 cm.
2.3. Other Equipments
Chain pin(made of steel) - Dia. 4mm -Length 25 to 50cm
Peg(made of wood) -Side 25mm -Length 150mm
Ranging rod(made of wood) -Dia.3cm -Length 2m to 3m
Ranging poles -Dia.6 to10cm -Length 4-8m
Offset rod -Dia.  3cm -Length 3m
Whites -Circular -Length 0.5 to 1m- for marking on a
chain line
Plumb bob:- It is used to transfer the end points of the chain onto ground while measuring the
distances in a hilly terrain. The length of the plumb bob is 50mm and weight varies from 2 to
5N.
*Ranging:- The process of marking a no. of intermediate points on a survey line joining two
stations in the field so that the length between them may be measured correctly. There are three
types of ranging:-
a) *Direct ranging:- When end stations are visible then direct ranging done. The minimum
no. of ranging rods required for direct ranging is three.
b) *Indirect ranging:- When end stations are not inter visible but visible from intermediate
points then indirect ranging is done. The minimum no. of ranging rods required for
indirect ranging is four. It is also known as reciprocal ranging. Example: Hillrock.
c) Random ranging:- Stations are neither visible from end points nor intermediate points
due to dense forest.
2.4. Errors in Chaining
The errors coming in chaining may be due to manual, instrumental or natural. All the
above errors are classified into three groups depending on nature:-
a) Cumulative errors:- The errors which occurs in the same direction and tend to
accumulate is called cumulative errors. Cumulative errors is of two types- (i) Positive
cumulative error (ii) Negative cumulative error. The positive cumulative error is occurring
due to length of the chain is shorter than its standard length. So correction for this is
always –ve. The negative cumulative error is occurring due to length of the chain/ tape is
longer than its standard length. So correction for this is always positive.
Note:- 1. Cumulative errors are always proportional to the length of the line.
2. Cumulative errors can be corrected by applying the required correction.
b) Compensating errors:- The errors which occurs in the either direction and tend to
compensate are called compensating error. It is occurring due to incorrect holding of the
chain, refinement in not made in plumbing etc.
Note:- 1.Compensating errors are proportional to square root of the length of the line.
2. The nature of error is not known so correction becomes impossible.
c) Accidental errors:-Accidental errors are occurring due to careless of the staffs involved
in chaining. It is proportional to square root of the number of observation taken.
2.5. Correction for Linear Measurements
C
Correction for standard length, Ca=  L (the sign of Ca will be same as C where C is
l
correction for absolute length)
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 Correction for alignment = l1 (1  cos  1 )  l 2 (1  cos  2 ) (-ve)
h2
*Correction for slope = (-ve)
2L
( P  P0 ) L
Correction for tension = (If the applied pull is more then +ve otherwise –ve)
AE
*Correction for temperature = (Tm  T0 )  L   (If the temperature is above normal then
correction is +ve and if it is below normal, then correction is –ve)
23 2
L W  Lw
*Correction for sag =   = (-ve) Where W =Lw
24  p  24 p
2

0.204 w AE
Normal tension, p =
p  p0
 Product of correct length and correct chain length = Product of the incorrect length and
incorrect chain length.
incorrect length of the chain
 True length = Measured length 
correct length of the chain
 *Line ranger is an instrument used for fixing the intermediate points on a chain line.
 Butt rods are used for measuring offset. It consists of two parts having one meter each and
are joined by hinge/rivets.
 Plaster’s laths are also used for ranging. It is made of soft wood. Its length varies 0.5m to
1m
 *Discrepancy is the difference between two measured values of the same quantity.
 Residual error is the difference between a measured quantity and the most probable value.
It is also called variation.
 The most probable error is defined as that error for which there are equal chances that the
true value will be less than the probable value or will be more than the probable value.
 *Accidental errors are directly proportional to N , where N is the number of
observations made.
 Angular errors of closures should not exceed 15 N .
3. Chain Surveying
It is a branch of survey in which only linear measurements are done and no angular
measurements are taken.
3.1. Suitability and Unsuitability of Chain Survey
S.No. Suitability Unsuitability
1 Fairly level ground Undulating ground
2 Small areas Large areas
3 Large scale plans are required Wooden countries
4 Open area Crowded areas
3.2. *Principle of Chain Surveying
The main principle of chain surveying is to divide the area into a number of triangles of
suitable sides. Since a triangle is the only simple plane geometrical figure which can be plotted
with the lengths of its sides alone.
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 *The triangle should not have any angle smaller than 300 and greater than 1200 is called
well-conditioned triangle and vice versa is called ill-conditioned triangle. The best triangle
is equilateral triangle for the chain survey.
3.3. Definition
a) *Base line:- The longest line in whole survey area of the main survey line is called base
line. Various survey stations are plotted with reference to the base line. Normally it is
measured with chain.
b) *Check (proof) lines:- The lines which run in the field to check the accuracy of the field
work is called check (proof) lines. The check line is not required for plotting the triangle.
Each triangle must has a check line.
c) Main survey station:-The point where two sides of a main triangle meet is called main
survey station. Main stations are the end of the lines, which command the
boundaries of the survey.
d) Main survey lines:- The line joining the main survey stations is called main survey lines.
It is also known as chain lines.
e) *Offset:- Offsets are the lateral measurement for locating the position of details. It makes
perpendicular or any other angle with survey lines. When the offset makes an angle of 900
with the survey line then it is called perpendicular offset otherwise it is called oblique
offset. If the length of offset is less than 15m then it is called short offset otherwise long
offset. The distance of the detail point from the foot of an offset is called length of the
offset. Offset measurement are taken and noted in the field and the complete operation is
known as taking offset. The fixing of a perpendicular offset with the help of chain/tape is
known as swing offset. The allowable length of offsets depends upon the following
factors:- i) accuracy required ii) scale of plotting iii) maximum error in laying off the
direction of the offsets iv) nature of ground.
f) Subsidiary stations - The stations, which are selected on main survey lines for running
auxiliary lines, are called subsidiary stations. It is also called tie station. It is necessary to
locate interior detail such as fences, hedges, building etc.
g) *Tie lines:- The chain line joining the subsidiary survey stations is called
auxiliary/subsidiary/tie lines. Tie lines are used to locate the interior details which are far
away from the main line.
 Accuracy of measurement in plotting upto 0.25mm to that of measurement 0.25cm.
 Accuracy required in the measurement: If the maximum displacement of point on the
drawing paper due to an error in measurement and that in direction are equal, then r =
cosec  where  = angular error in the direction 1 in n be the accuracy with which length
of the offset is measured.
3.4. Obstacles in Chaining
i) Obstacles in ranging but not in chaining. Ex:- Hill rock.
ii) Obstacles in chaining but not in ranging. Ex:- River & Ponds.
iii) Obstacles in both ranging and chaining. Ex:- Tall buildings.
3.5. Right Angle Instruments
a) *Cross staff
i) Open cross staff (900)
ii) French cross staff (450 and 900)
iii) Adjustable cross staff (900)
b) *Optical square:- It is used for setting out a line at 90 degree to another line and works
principle of double reflection.

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c) Prism square:- It works on same principle as that of optical square used for setting out a
line at 90 degree to another line. Its merit is that no adjustment is required because angle
b/w reflecting surfaces is constant that is 45 degree.
 Cross staff survey is used for cadastral map.
 In the chain surveying the accuracy of survey depends on the follower.
 If the chain is too long, the measured distance will be less and if the chain is too short, the
measured distance will be more.
 Sign of correction is always opposite to that of the error.
 *Bergchrund:- It is a topographical feature in water bodies. It is crevasse at the junction
of a glacier or snowfield with a steep upper slope.
4. Compass Surveying
The branch of surveying in which directions of survey lines are measured by a compass
and their lengths by chaining or taping directly on the surface of the earth, is called compass
surveying. *This surveying is suitable for those place where the effect of magnetic effect is
least or none. There are two types of compass named prismatic compass and surveyor compass.
Prismatic compass is most suitable types of compass and are mostly used. The main difference
between prismatic compass and surveyor compass are tabulated below:-
# *Comparison of prismatic and surveyor compass
Item Bearing Graduations Tripod Scale Magnetic needle
P. W.C.B Inverted(0-3600) Not Attached to the Broad magnetic
Compass 00 at south & essential needle needles
CW
S. R.B Erect(0-900) Must Attached to the Edge bar
Compass box magnetic needle.

4.1. Traverse
Traverse is a series of straight lines connected together to form an open or closed loop.
There are two types of traverse:-
a) Closed traverse:-A traverse which either emanates from a station and closes at the
same station or runs between two stations whose co-ordinates are known in terms
of a common system of co-ordinate.
In closed traverse
*Sum of internal angles = (2n-4) * 900
*Sum of external angles = (2n+4) * 900
*Algebraic sum of deflection angles =3600
b) Open traverse:-A traverse which neither returns to its starting station nor ends on
another station, is known as open traverse.
 Closed traverse is better than open traverse for considering the degree of accuracy.
 Theodolite traverse is the most accurate traverse.
*True meridian is the line passing through the North Pole & South Pole of the earth. The
smaller angle which a survey line makes with true meridian is called azimuth.
Magnetic meridian is the standard reference line shown by a freely balanced magnetic needle
free from any external influence. It does not coincide with the true meridian except certain
localities.
Arbitrary meridian is the convenient direction assumed for measuring bearing of a survey
lines.

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The true meridian of a central place is sometimes taken as a reference meridian for the whole
state, such a reference meridian is called grid meridian.
*Bearing of a line is its direction with respect to a reference line. Following are the different
types of the bearing:-
a) True bearing:- The bearing of a line is a horizontal angle which it makes with a true
meridians through one of the extremities of the line. It is always constant for a specified
line.
b) Magnetic bearing:- The bearing of a line is a horizontal angle which it makes with the
magnetic meridian through one of the extremities of the line. It is measured by compass.
c) Arbitrary bearing:- The bearing of a line is a horizontal angle which it makes with the
arbitrary meridian through one of the extremities of the line. It is measured by compass.
d) Grid bearing:- The bearing of a line is a horizontal angle which it makes with the grid
meridian (Grid meridian is the north direction of the north-south grid lines of the map)
through one of the extremities of the line.
 Whole circle bearings are measured in the clockwise direction with reference to magnetic
north while quadrantal /reduced bearings are measured with respect to magnetic North/
South towards east or west.
4.2. *Conversion of W.C.B in Q.B.
Case W.C.B. Role for Q.B Quadrant
1 00-900 W.C.B. NE
2 900-1800 1800-W.C.B SE
3 1800-2700 W.C.B-1800 SW
4 2700-3600 3600-W.C.B NW
0
5 0 N
6 900 E900
7 1800 S
8 2700 W900
.
 The bearing of a line in the direction of the progress of survey is called fore bearing while
the bearing in the opposite direction of the progress of survey is called back bearing. The
difference between the back bearing and fore bearing of a line should be always 1800 if the
stations are free from local attraction.
Note:-1.*Back bearing = Fore bearing ± 1800 (Use +ve sign if the fore bearing
is less than 1800 and –ve sign if the fore bearing is more than 1800)
2. Add the included angle measured clockwise to the bearing of the previous
line. If the sum is
more than 1800, deduct 1800
more than 5400, deduct 5400
less than 1800, add 1800, to get the bearing of next line.
3. Line of sight:- It is defined as line of sight by the object vane and the eye slit both
attached to the compass box.
4.3. *Deflection angle, Dip angle & Declination
a) Deflection angle:- Deflection angle is the included angle between the prolongation of the
previous line and the succeeding line. Clockwise deflection is called right deflection and is
additive. Anticlockwise deflection is called left deflection and is subtractive.

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b) Dip:- Dip is the inclination between the longitudinal axis of a magnetic needle and the
horizontal plane through its pivot. It is a vertical angle. In the northern hemisphere, the
north end and in southern hemisphere, south end of the needle, deflects downwards. It is
the vertical angle whose value varies from place to place. It is zero at the equator and 900
at the north and south magnetic poles. The line joining points of equal dip is called is
isoclinic line.
c) Magnetic declination:-Magnetic declinationis the horizontal angle between true north and
magnetic north. If the magnetic meridian is eastern side of true meridian, the angle of
declination is said to be eastern (positive) declination. If the magnetic meridian is western
side of true meridian, the angle of declination is said to be western (negative) declination.
When both true and magnetic meridian coincide, magnetic declination is zero . The line
joining the points of equal declination is called isogonic line while the zero declination is
called agonic line. The magnetic declination of a place is not constant but varies from time
to time. The variation is more near poles and less on the equator. The variation is classified
as:-
i) Secular variation (0.021 to 121):- Variation over a very long period (Approximately 250
Years).
ii) Annual variation (11 to 21):- Variation within a year- more during summer and less
during winter.
iii) Diurnal variation (31 to121 ):- Variation within same day more during day time and less
during night time.
iv) Irregular variation ( 10 to 20) – Due to earthquake, volcanic, storm, solar influence etc.
True bearing = Magnetic bearing  Declination (if declination is east then positive and
negative when west). (SADI)
4.4. *Adjustment of Compass
There are two types of adjustment temporary and permanent adjustment. Here only brief
description of temporary adjustment is done. There are three steps in temporary adjustment:-
a) Centering:- The process of making the pivot exactly vertically over the ground station
mark, is called centering.
b) Levelling:- The process of holding the compass in such a way that its graduated ring
swings freely, is called levelling.
c) Focussing the prism:- The process of moving up or down the prism for obtaining the
figures and graduations sharp and clear, is called focusing the prism.
4.5. *Local Attraction
Local attraction is defined as an influence, which prevents the magnetic needle from
pointing to the magnetic north in a given locality. It occurs due to effect of electric wire,
magnet, iron ores etc.The correct bearing of a line is obtained, by calculating the local attraction
of each station and then applying the required correction, starting from the unaffected bearing.
 It is detected by taking back bearing and fore bearing of a line.
 *The difference between back bearing and fore bearing of a line should be 1800 if there is
no local attraction.
 The difference between back bearing and fore bearing of a line should be 1800 if both the
stations are equally affected in same direction.

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