1. Introduction To Surveying Mr. Vedprakash Maralapalle, Asst. Professor
Department: B.E. Civil Engineering
Subject: Surveying – I
Semester: III
Teaching Aids Service by KRRC Information Section

2. Primary Divisions of Surveying
We know that the shape of the earth is spheroidal. Thus the surface is obviously curved. Surveying is primarily divided into two types considering the curvature of the earth’s surface.
Plane Surveying
Geodetic Surveying

3. Plane Surveying
The plane surveying is that type of surveying in which earth surface is considered as a plane and the curvature of the earth is ignored.
In such surveying a line joining any two stations is considered to be straight.
The triangle formed by any three points is considered as a plane triangle, and the angles of the triangle are considered as plain angles.
Surveying is carried out for a small area of less than 250 km2 .
It is carried out by local or state agencies like R & B department, Irrigation department, Railway department.

4. Plane Surveying

5. Geodetic Surveying
The geodetic Surveying is that type of surveying in which the curvature of the earth is taken into account.
It is generally extended over larger areas. The line joining any two stations is considered as curved line.
The triangle formed by any three points is considered to be spherical and the angles of the triangle are considered to be spherical angles.
Geodetic surveying is conducted by the survey of India Department and is carried out for a larger area exceeding 250 km2

6. Geodetic Surveying

7. Plane Surveying Vs Geodetic Surveying
No.
Plane Surveying
Geodetic Surveying 1
The earth surface is considered as plain Surface.
The earth surface is considered as Curved Surface. 2.
The Curvature of the earth is ignored
The curvature of earth is taken into account. 3
Line joining any two stations is considered to be straight
The line joining any two stations is considered as spherical. 4.
The triangle formed by any three points is considered as plain
The Triangle formed by any three points is considered as spherical. 5.
The angles of triangle are considered as plain angles.
The angles of the triangle are considered as spherical angles. 6.
Carried out for a small area < 250 km2
Carried out for a large area > 250 km2

8. Fundamental Principles of Surveying
Two basic principles of surveying are:
Always work from whole to the part.
To locate a new station by at least two measurements ( Linear or angular) from fixed reference points.

9. Always work from whole to the part:
According to the first principle, the whole survey area is first enclosed by main stations (i.e.. Control stations) and main survey lines.
The area is then divided into a number of divisions by forming well conditioned triangles.
The main survey lines are measured very accurately with precise survey instruments.
The remaining sides of the triangle are measured.
The purpose of this method of working is to control accumulation of errors.
During measurement, if there is any error, then it will not affect the whole work, but if the reverse process is followed then the minor error in measurement will be magnified.

10. Work from Whole to the Part

11. To locate a new station by at least two measurements
According to the second principle the points are located by linear or angular measurement or by both in surveying.
If two control points are established first, then a new station can be located by linear measurement.
Let A & B are control points, a new point C can be established.

12. Instruments Used in Chaining
The following instruments are used while chaining.
Chains
Tapes
Arrows
Ranging rods and offset rods
Pegs
Plumb bob

13. Instruments Used in Chaining
Chains
Metric Chain
Gunter’s Chain or Surveyor’s Chain
Engineer’s Chain
Revenue Chain
Steel Band or band chain

14. CHAIN
The chain is composed of 100 or 150 pieces of links, made up of 4 mm diameter galvanized mild steel wire.
The ends of the chain provided with brass handles for dragging the chain on the ground.
The end links include the handles. Tallies are provided at regular interval

15. METRIC CHAIN The chains are made in length of 20 and 30 meters.
The length of the chain is marked over the handle to indicate the length.
The length of each link is 0.2 m (20cm) in 20m chain is provided with 100 links and 30 m chain divided into 150 links.
Tallies are fixed at every five-meter length and small brass rings are provided at every meter length.
This chain is suitable for measuring distances along fairly level ground.

17. ENGINEER’S CHAIN
The engineer’s chain is 100ft long and is divided into 100 links. So each link is 1ft.
It is used on all engineering survey works.
The distances measured with the engineer’s chain are recorded in feet and decimals (Tallies are provided at every 10 links i.e. 10 ft).

18. GUNTER'S CHAIN It is 66ft long and divided into 100 links.
So each link is of 0.66ft.
It is also called surveyor’s chain. It is very convenient for measuring distances in miles.

19. REVENUE CHAIN
The revenue chain is 33ft long and divided into 16 links .
It is mainly used in cadastral survey.

20. STEEL BAND
It consists of a ribbon of steel 16 mm wide with a brass swivel handle at each end and is 20 or 30 m in length.
It is graduated in metres, decimeters, centimeters on one side and 0.2 m links on the other.
For more accurate work, the steel band is preferred.

21. The advantages of the chain are :
It is very suitable for rough usage.
It can be easily repaired in the field.
It can be read easily and quickly.
It can withstand wear and tear.

22. Disadvantages of the chain are :
They are heavy and take too much time to open or fold.
They become longer or shorter due to continuous use.
When measurement is taken in suspension, the chain sags excessively.

23. TAPES The following are the various types of tapes
i) Cloth tape or Linen tape
ii) Metallic tape
iii) Steel tape
iv) Invar tape
v) Digital tape

24. Cloth tape or Linen tape
Such a tape is made up of closely woven linen and is varnished to resist moisture.
It is 12 to 16 mm wide and available lengths of 10 & 15m.
It is very light and handy, but not so accurate. For very precise measurements, it is not used.
The linen tape may be used for taking subsidiary measurements such as offsets.
It is easily affected by damp. When the tape gets wet, it shrinks and care should be taken that it is not wound up until is cleaned and dried.
It stretches easily and is likely to twist and tangle. It is therefore little used in surveying.

25. METALLIC TAPE
It is made from good quality cotton or linen and is reinforced with fine brass or copper wires to make it durable.
This prevents stretching of fibres and is therefore, better than simple linen tapes.
They are also not suited for very precise measurements.
This tape is available in lengths of 15, 20 and 30 m.

26. STEEL TAPE
The steel tape is made of steel ribbon or stainless steel, of width varying from 6 to16 mm.
The commonly available lengths are 10,15,20,30 and 50m.
It is used for very precise measurements and for checking the accuracy of chain lengths.

27. INVAR TAPE
Invar tape is made up of an alloy of steel 64% and nickel 36% and possesses a very low coefficient of thermal expansion (0.6 × 10-4 for 1°C).
It is made in form of a ribbon of width 6mm and is available in lengths of 30, 50 & 100m.
The tapes are extremely brittle and expensive. It is generally used in the triangulation survey conducted by the Survey of India department.

28. DIGITAL TAPE
This type of device usually has LCD screen connected to a traditional measuring tape.
LCD screen will display the length.
To store & recall measurements.
Useful during home repair or other projects that require frequent & numerous measurements.

29. Arrows

30. Ranging Rods

31. RANGING ROD OR OFFSET ROD
Ranging rods are used to range some intermediate points in the survey line.
Such roads are made of seasoned timber or seasoned bamboo, sometimes GI pipes of 25mm.
The length of the ranging rod is either 2m or 3m. The lower end of the rod is pointed and provided with an iron shoe.
Ranging rods are divided into equal parts 0.2m long and they are painted alternately black or red and white.

32. PEGS Wooden pegs are used to mark the positions of stations.
They are made of hard timber and are tapered at one end.
They are usually, 2.5 cm square and 15 cm long.

33. ARROW
They are also called marking or chaining pins, and are used to mark the end of each chain during the process of chaining i.e. used for counting the number of chains while measuring a chain line.
They are made of good quality metallic wires of 4 mm in diameter and are made 400 mm in length, are pointed at one end for inserting into the ground.

34. PLUMB BOB
A plumb-bob or a plummet is a weight, usually with a pointed tip on the bottom, that is suspended from a string and used as a vertical reference line, or plumb-line.

35. RANGING
The process of establishing intermediate points on a straight line between two end points is known as ranging.
Ranging must be done before a survey line is chained. Ranging may be done direct observation by the naked eye.
Generally, ranging is done by the naked eye with the help of three ranging rods.

36. Direct Ranging
If the first and last points are intervisible this method is possible.
Stations A and B in which an intermediate point C is to be located.
Point C is selected at a distance slightly less than a chain length. At points A and B ranging rods are fixed.
The assistant holds another ranging rod near C.
Surveyor positions himself approximately 2 m behind station A and looking along line AB directs the assistant to move at right angles to the line AB till he aligns the ranging rod along AB.
Then surveyor instructs the assistant to mark that point and stretch the chain along AC.

37. Direct Ranging

38. Direct Ranging

39. Direct Ranging

40. Direct Ranging

41. Indirect or Reciprocal Ranging
Due to intervening ground, if the ranging rod at B is not visible from station A, reciprocal ranging may be resorted. Figure shows this scheme of ranging.
It needs two assistants one at point M and another at point N, where from those points both station A and station B are visible.
It needs one surveyor at A and another at B. To start with M and N are approximately selected, say M1 and N1.
Then surveyor near end A ranges person near M to position M2 such that AM2N1 are in a line.
Then surveyor at B directs person at N, to move to N2 such that BN2M2 are in a line.
The process is repeated till AMNB are in a line.

42. Indirect or Reciprocal Ranging

43. Indirect or Reciprocal Ranging

48. Code of Signals for Ranging
Sr.No.
Signal by the Surveyor
Action by the Assistant 1.
Rapid sweeps i.e. up and down movement with right hand on right side.
Move considerably to the right. 2.
Rapid sweeps i.e. up and down movement with left hand on left side.
Move considerably to the left. 3.
Slow sweeps with right hand on right side.
Move slowly to the right. 4.
Slow sweeps with left hand on left side.
Move slowly to the left. 5.
Right arm extended
Continue to move to the right. 6.
Left arm extended
Continue to move to the left. 7.
Both hands above head & brought down.
Correct. 8.
Both the arms extended forward horizontally & depressed down.
Fix the ranging rod.

49. UNFOLDING & FOLDING A CHAIN
To open a chain, the strap is unfastened and the two brass handles are held in the left hand and the bunch is thrown forward with the right hand.
Then one chainman stands at the starting station by holding one handle and the other moves forward by holding the other handle until the chain is completely extended.

50. Folding:
To fold the chain, a chainman should move forward by pulling the chain at the middle.
Then the two halves of the chain will come side by side. After this, commencing from the central position of the chain, two pairs of links are taken at a time with the right hand and placed on the left hand alternately in both direction.
Finally, the two brass handles will appear at the top. The bunch should be then fastened by the strap.

51. TESTING A CHAIN

52. ADJUSTMENT OF CHAIN If the chain is found to be too long.
Closing up the joints of the connecting rings (that may be opened out).
Hammering back to the shape of the elongated rings.
Replacing some of the worn out (old) rings with new ones.
Removing one or more of the small rings.

53. ADJUSTMENT OF CHAIN
If the chain is found to be too short, it may be adjusted by
Straightening any bent links.
Replacing some of the worn out rings with new ones .
Replacing a few of the rings by those of the larger size.

54. Obstacle in chaining When chaining is free but vision is obstruction
When chaining is obstructed but vision is free
When chaining and vision are both obstruction

55. Chaining free but vision obstructed
The end stations are not visible from intermediate points when a jungle area comes across the chain line.

56. Chaining free but vision obstructed
Let AB be the actual chain line which cannot be ranged & extended because of interruption by jungle. Let the chain line be extended up to R. A point P is selected on the chain line and random line PT is taken in a suitable direction. Point C,D & E are selected on the random line , & perpendicular are projected from them. The perpendicular at C meets the chain line at C1. Theoretically the perpendicular at D and E will meet the chain line at D1 and E1 Now, the distances PC,PD,PE and CC1 are measured from triangle PDD1 and PCC1 DD1/PD = CC1/PC DD1 = CC1/PC X PD ………………(1) From triangle PEE1 AND PCC1 EE1/PE = CC1/PC EE1 = CC1/PC X PE …………………..(2) From 1 & 2 the lengths DD1 & EE1 are calculated. These calculated distances are measured along the perpendicular at D & E. point D1 & E1 should lie in the change line AB . Distance PE1 =

57. Chaining obstructed but vision free
Such a problem arises when a pond or a river comes across the chain line.
Suppose AB is chain line . Two point C &D selected on opposite banks of the pond. Equal perpendicular CE &DF are erected at C & D. the distance EF is measured.
CD = EF

58. Chaining and Vision obstructed
Such a problem arises when a building comes across the chain line.
Suppose AB is the chain line. Two points C & D are selected on it at one side of the building. Equal perpendicular CC1 and DD1 are erected. The line C1D1 is extended until the building is crossed. On the extended line, two point E1 and F1 are selected. Then perpendicular E1E & F1F are so erected that
E1E = F1F = D1D = C1C
Pont C,D,E & F will lie on the same straight line AB.
Distance D1E1 = DE

59. Chaining on Sloping Ground
The object of survey is to prepare a plan or a map. In the plan or a map the distance plotted between any two points is always a straight line.
Even if the chaining is done on a sloping ground, this sloping distance is converted into horizontal equivalent distance while plotting.
There are two methods of finding out horizontal distance while on a sloping ground.
Direct Method
Indirect Method

60. Continue.. Direct Method
This method is also called method of stepping in this method, the distance is measured in small horizontal stretches. A suitable length of chain or tape say l1 is taken. The follower holds the zero end of the tape at a point on the top of the hill or sloping ground. i.e. at point A. The tape is stretched horizontally from A at small length l1 of 3 to 5 m. The point at the end of the l1 is dropped and marked on the ground as a1. From a1, again tape is stretched exactly in a horizontal plane at a convenient step l2 and drop end of l2 on the ground as b1. Likewise entire length of line on the sloping ground is measured.
Finally the total horizontal length of the line AB, i.e. D is obtained
D= l1 + l2 + l3 + ……… ln
Where ln= the last step for the given survey line

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66. Indirect Method on sloping Ground
Clinometer

67. Measuring slope with a calinometer
A calinometer is a graduated semicircular protractor. A plumb bob is suspended from point O with thread. When the straight edge is just horizontal, the thread asses through 0 degree .
When straight edge is tilted, the thread remains vertical, but passes through a graduation on the arc which shows the angle of slope.
Suppose C & D are two points on slopping ground. Two ranging rods are fixed at these points. Then two other points C1 and D1 are marked on the ranging rods so that CC1 = DD1.
The clinometer is placed in such a way that its centre just touches mark C1 , the calinometer is then inclined gradually until the points P1,P2 & D1 are in the same straight line.
At this position the thread of the clinometer will how an angle which is the angle of slope of the ground. Suppose this angle is α. The slopping distance CD is also measured. Let it be L
Horizontal distance CB= L cos α

69. References
Surveying and Levelling: Vol-I and II: Kanetkar and Kulkarni, Pune Vidyarthi Griha, Pune.
Surveying and Levelling: N N Basak, Tata McGraw Hill, New Delhi.
Surveying: R. Agor, Khanna Publishers.
Surveying: Vol-I: Dr K.R. Arora, Standard Book House.
Kanpur and IIT Madras.
Google images.