vision of the institute mission of the institutethe students shall be informed about their...

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i Dept. of Civil Engineering Basic Surveying Practice Manual - 17CVL38

VISION OF THE INSTITUTE

Become a premier institution imparting quality education in engineering and

management to meet the changing needs of society

MISSION OF THE INSTITUTE

M1. Create environment conducive for continuous learning through quality

teaching and learning processes supported by modern infrastructure

M2. Promote Research and Innovation through collaboration with industries

M3. Inculcate ethical values and environmental consciousness through holistic

education programs


ii Dept. of Civil Engineering Basic Surveying Practice Manual - 17CVL38

DEPARTMENT OF CIVIL ENGINEERING

VISION

To become a leading department oriented to serve the basic wants of human

being related to food, air, shelter and transportation, by providing quality

education.

MISSION

M1. Create a favorable environment for learning, teaching & continuous

improvement for implementation of various civil engineering facilities.

M2. Promote professionalism, innovation and research through collaboration

with industries to realize cost & resource effective, stable, quality structures.

M3. Inculcate environmental consciousness and ethical values through

interconnected training programs to ensure sustainability and client satisfaction.


iii Dept. of Civil Engineering Basic Surveying Practice Manual - 17CVL38

PROPROGRAM EDUCATION OBJECTIVES-PEO’s

The program educational objectives of Civil Engineering are, to enable students in,

PEO-1: Developing careers in government and private civil engineering organizations and

other professionally related domains

PEO-2: Pursuing higher studies, and research to develop innovative solutions and technologies

in civil engineering and other multi-disciplinary areas

PEO-3: Improving professional and personal traits aligned to professional ethics and

environmental compulsions

PEO-4: Professional leadership and Successful entrepreneurship

PROGRAM OUTCOMES-PO’s

1. Engineering knowledge: Apply the knowledge of mathematics, science, engineering

fundamentals, and an engineering specialization to the solution of complex engineering

problems.

2. Problem analysis: Identify, formulate, review research literature, and analyze complex

engineering problems reaching substantiated conclusions using first principles of mathematics,

natural sciences, and engineering sciences.

3. Design/development of solutions: Design solutions for complex engineering problems and

design system components or processes that meet the specified needs with appropriate

consideration for the public health and safety, and the cultural, societal, and environmental

considerations.

4. Conduct investigations of complex problems: Use research-based knowledge and research

methods including design of experiments, analysis and interpretation of data, and synthesis of

the information to provide valid conclusions.

5. Modern tool usage: Create, select, and apply appropriate techniques, resources, and modern

engineering and IT tools including prediction and modeling to complex engineering activities

with an understanding of the limitations.

6. The engineer and society: Apply reasoning informed by the contextual knowledge to assess

societal, health, safety, legal and cultural issues and the consequent responsibilities relevant to

the professional engineering practice.

7. Environment and sustainability: Understand the impact of the professional engineering

solutions in societal and environmental contexts, and demonstrate the knowledge of, and need


iv Dept. of Civil Engineering Basic Surveying Practice Manual - 17CVL38

for sustainable development.

8. Ethics: Apply ethical principles and commit to professional ethics and responsibilities and

norms of the engineering practice.

9. Individual and team work: Function effectively as an individual, and as a member or leader

in diverse teams, and in multidisciplinary settings.

10. Communication: Communicate effectively on complex engineering activities with the

engineering community and with society at large, such as, being able to comprehend and write

effective reports and design documentation, make effective presentations, and give and receive

clear instructions.

11. Project management and finance: Demonstrate knowledge and understanding of the

engineering and management principles and apply these to one’s own work, as a member and

leader in a team, to manage projects and in multidisciplinary environments.

12. Life-long learning: Recognize the need for, and have the preparation and ability to engage in

independent and life-long learning in the broadest context of technological change.

PROGRAM SPECIFIC OUTCOMES-PSO’s

PSO-1: Comprehend, analyze and design alternatives for execution of civil engineering

facilities

PSO-2: Apply Standard Codes of Practices and schedule of rates for planning, design, quality

control, estimating & costing of civil engineering projects.

PSO-3: Evaluate the buildings for resource conservation.


v Dept. of Civil Engineering Basic Surveying Practice Manual - 17CVL38

PREFACE

The Basic Surveying Practice Manual contains material that is informational and

instructional, and that sets forth uniform guidelines and accepted practices in civil construction.

The purpose of the manual is to provide uniform guidelines for implementing survey decisions,

and to assure quality and continuity in collection of survey data. The use of the Basic

Surveying PracticeManual is to assure appropriate execution of projects in conformity with the

operational needs of departments dealing with survey data collection and execution of all civil

engineering works. The objective of this manual is not to serve as a general purpose text on the

practice of surveying.

The manual is written in a clear and easy-to-read style, presenting fundamentals of

geodetic engineering at a level that can be quickly grasped by a beginner.

The manual consists of vision and mission of the institute and department. Attendance

requirements and eligibility of a student to attend the geodetic engineering laboratory is

mentioned. Evaluation scheme of student is clearly specified. Step wise procedure for each

experiment as per the university scheme to be conducted is given in the manual along with

related questions. The manual also deals with the demonstration of major instruments used in

preliminary surveying.


vi Dept. of Civil Engineering Basic Surveying Practice Manual - 17CVL38

Regulations Governing

THE DEGREE OF BACHELOR OF ENGINEERING

ATTENDANCE REQUIREMENT

Each semester is considered as a unit and the candidate has to put in a minimum

attendance of 85% in each subject with a provision of condonation of 10% of the

attendance by the Vice-Chancellor on the specific recommendation of the Principal of the

college where the candidate is studying, showing some reasonable cause such as medical

grounds, participation in University level sports, cultural activities, seminars, workshops

and paper presentation, etc.

The basis for the calculation of the attendance shall be the period prescribed by the

University by its calendar of events. For the first semester students, the same is reckoned

from the date of admission to the course as per CET allotment.

The students shall be informed about their attendance position periodically by the

colleges so that the students shall be cautioned to make up the shortage.

A Candidate having shortage of attendance in one or more subjects shall have to repeat

the whole semester and such candidates shall not be permitted to take admission to next

higher semester. Such students shall take readmission to the same semester in the

subsequent academic year.

INTERNAL ASSESSMENT MARKS

There shall be a maximum of 40 Internal Assessment Marks in each practical papers,

the IA marks shall be based on the laboratory journals/reports and one practical test.

A candidate failing to secure a minimum of 50% of the IA marks (20/40) in Practical,

50% of marks in project work, shall not be eligible for the practical / project in the

University examination. For a pass in a Practical/Project/Viva-voce examination, a

candidate shall secure a minimum of 40% of the maximum marks prescribed for the

University Examination in the relevant Practical/Project/Viva-voce.


vii Dept. of Civil Engineering Basic Surveying Practice Manual - 17CVL38

BASIC SURVEYING PRACTICE

[As per Choice Based Credit System (CBCS) scheme]

SEMESTER – III

Subject Code : 17CVL38 CIE Marks : 40

No. of Practical Hrs / Week : 03(1 hour instruction + 2 hours lab) Exam Hours : 03

Total No. of Practical Hrs. : 40 SEE Marks : 60

Sl.No. Modules TeachingHours

1.

a) Measurements of distances using tape along with horizontal planes and

slopes, direct ranging. b) Setting out perpendiculars. Use of cross staff,

optical square

03

2. Obstacles in chaining and ranging – Chaining but not ranging, ranging but

not chaining, both ranging and chaining. 03

3. Measurements of bearings / directions using prismatic compass, setting of

geometrical figures using prismatic compass. 03

4. Measurement of bearings of sides of a closed traverse and adjustment of

closing error by Bowditch method. 03

5. Determination of distance between two inaccessible points using compass

and accessories 03

6. Determination of reduced levels of points using dumpy level/auto level

(simple leveling) 03

7. Determination of reduced levels of points using dumpy level/auto level

(differential leveling and inverted leveling) 03

8. To determine the difference in elevation between two points using

Reciprocal leveling and to determine the collimation error 03

9.

To conduct profile leveling, cross sectioning and block leveling. Plotting

profile and cross sectioning in excel. Block contour on graph paper to

scale

03

10. Measurement of horizontal angle by repetition and reiteration methods

and Measurement of vertical angles using theodolite. 03

11.

Determination of horizontal distance and vertical height to a base

inaccessible object using theodolite by single plane and double plane

method.

03

12. To determine distance and elevation using tachometric surveying with

horizontal and inclined line of sight. 03


viii Dept. of Civil Engineering Basic Surveying Practice Manual - 17CVL38

Sl.No. Modules TeachingHours

13. Closed traverse surveying using Theodolite and applying corrections for

error of closure by transit rule. 03

14. Demonstration of Minor instruments Clinometer, Ceylon Ghat tracer, Box

sextant, Hand level, Planimeter, nautical sextant and Pentagraph 03

Reference Books:

1. S.K. Duggal, “Surveying Vol.1”, Tata McGraw Hill Publishing Co. Ltd. NewDelhi. – 2009.

2. K.R. Arora, “Surveying Vol. 1” Standard Book House, New Delhi. – 2010


ix Dept. of Civil Engineering Basic Surveying Practice Manual - 17CVL38

COURSE OUTCOME

Upon successful completion of this course, students should be able to:

KL-Knowledge Level, U- Understand, Ap-Apply

Subject code: 17CVL38 Subject: BASIC SURVEYING PRACTICE

COs COURSE OUTCOMES KL No. of

sessions

CO1

Apply the basic principles of engineering surveying for linear and

angular measurements. Ap 20

CO2

Comprehend effectively field procedures required for a professional

surveyor. Ap 17

CO3

Use techniques, skills and conventional surveying instruments necessary

for engineering practice.

U

3


x Dept. of Civil Engineering Basic Surveying Practice Manual - 17CVL38

EVALUATION SCHEME

VTU LAB EVALUATION PROCESS

WEEK WISE VALUATION OF EACH EXPERIMENT

SL.NO ACTIVITY MARKS

2017 SCHEME

1 Write up 5

2

Conduction (7 – Field

Conduction + 3 – Lab

Instruction)

10

TOTAL 15

FINAL INTERNAL ASSESSMENT CALCULATION


2017 SCHEME

1 Average of Weekly Entries 30

2 Internal Assessment Reduced To 10

TOTAL 40

INTERNAL ASSESSMENT EVALUATION (End of Semester)


2015 SCHEME

1 Write-Up 9

2 Conduction 42

3 Viva Voce 9

TOTAL 60


xi Dept. of Civil Engineering Basic Surveying Practice Manual - 17CVL38

CONTENTS

LABORATORY CERTIFICATE _______________________Error! Bookmark not defined.

PROPROGRAM EDUCATION OBJECTIVES-PEO’s ______________________________ iii

PROGRAM OUTCOMES-PO’s ________________________________________________ iii

PROGRAM SPECIFIC OUTCOMES-PSO’s ______________________________________ iv

PREFACE _________________________________________________________________ v

COURSE OUTCOME ________________________________________________________ ix

EVALUATION SCHEME_____________________________________________________ x

CONTENTS ________________________________________________________________ xi

GENERAL INSTRUCTIONS _________________________________________________ xiv

LIST OF EXPERIMENTS ____________________________________________________ xv

IMPORTANCE OF BASIC SURVEYING PRACTICE ____________________________ xvi

EXPERIMENT 1- ___________________________________________________________ 1

a) Measurement of distances using tape along horizontal planes and slopes, direct/indirect

ranging,____________________________________________________________________ 1

b) Setting out perpendiculars. Use of cross staff, optical square. ______________________ 1

Measurement of Distance ________________________________________________ 1

Measurement of Distance on Slopping Ground _______________________________ 4

Setting Out of Perpendiculars ____________________________________________ 6

EXPERIMENT 2- Obstacles in chaining and ranging – Chaining but not ranging, ranging but

not chaining, both ranging and chaining. __________________________________________ 9

Obstacle to Ranging but Not Chaining _____________________________________ 9

Obstacle to Chaining but Not Ranging ____________________________________ 10

Obstacle to Both Chaining and Ranging ___________________________________ 13

EXPERIMENT 3- Measurement of bearings/directions using prismatic compass, setting of

geometrical figures using prismatic compass ______________Error! Bookmark not defined.

EXPERIMENT 4- Measurement of bearings of sides of a closed traverse and adjustment of

closing error by Bowditch method. _____________________________________________ 22


xii Dept. of Civil Engineering Basic Surveying Practice Manual - 17CVL38

EXPERIMENT 5 - Determination of distance between two inaccessible points using compass

and accessories _____________________________________________________________ 26

EXPERIMENT 6 - Determination of reduced levels of points using dumpy level/auto level

(simple leveling). ___________________________________________________________ 29

Determination of RL of an object above the plane of collimation using inverted leveling. __ 35

EXPERIMENT 8 - To determine the difference in elevation between using reciprocal leveling

and to determine the collimation error ___________________________________________ 36

EXPERIMENT 9 - To conduct profile leveling, cross sectioning and block leveling. Plotting

profile and cross sectioning in excel. Block contour on graph paper to scale _____________ 38

Profile Levelling______________________________________________________ 38

Cross Sectioning _____________________________________________________ 41

Block leveling, preparation of contour plan using excel. Use of planimeter/graph and

computations of Areas and volumes. ____________________________________________ 44

Block Levelling ______________________________________________________ 44

Contouring __________________________________________________________ 46

EXPERIMENT 10- Measurement of horizontal angle by repetition and reiteration methods and

measurement of vertical angles using theodolite ___________________________________ 47

Method of Repetition __________________________________________________ 47

Measurement of Horizontal Angle-Method of Reiteration _____________________ 51

Measurement of vertical angles using theodolite. __________________________________ 54

EXPERIMENT 11-Determination of horizontal distance and vertical height to a base

inaccessible object using theodolite by single plane and double plane method. ___________ 57

EXPERIMENT 12- to determine distance and elevation using tacheometric surveying with

horizontal and inclines line of sight. ____________________________________________ 66

EXPERIMENT 13-Closed traverse surveying using theodolite and applying corrections for

error of closure by transit rule. _________________________________________________ 70

EXPERIMENT 14 - Demonstration of minor instruments ___________________________ 73

Hand Level __________________________________________________________ 73

Box Sextant _________________________________________________________ 74

Clinometer __________________________________________________________ 75

Ceylon Ghat Tracer ___________________________________________________ 76


xiii Dept. of Civil Engineering Basic Surveying Practice Manual - 17CVL38

Planimeter __________________________________________________________ 77

Pentagraph __________________________________________________________ 79

Additional Exercise _________________________________________________________ 81

Viva-Voce ________________________________________________________________ 82

Linear Measurements __________________________________________________ 82

Chain Surveying ______________________________________________________ 82

Compass Traversing ___________________________________________________ 83

Levelling ___________________________________________________________ 83

Theodolite Traversing _________________________________________________ 84

Tacheometric Survey __________________________________________________ 85


xiv Dept. of Civil Engineering Basic Surveying Practice Manual - 17CVL38

GENERAL INSTRUCTIONS

1. Students should be regular to the lab.

2. Shoe, Apron, Observation book, Manual, and Calculator and water bottle are must before

entering the lab.

3. Failure to bring the observations and record regularly will result in deduction in 1 mark

every week.

4. List of instruments are to be entered in the issue register before taking it to the field.

5. Instruments are to be returned strictly to the lab instructors only.

6. The instruments should be checked at the time of issue and return.

7. The instrument should be replaced by a new one in case of damage/missing.

8. The instrument should not be left unattended in the field.

9. The instruments should be protected from sun, rain and dust.

10. Tape/chain should be read correctly while measuring distances.

11. Arrows must be fixed at the end of chain line firmly.

12. The compass box must be tapped gently after the needle comes to rest.

13. The vibrations of the magnetic needle should be stopped by gently pressing the knob.

14. The compass/level should be set up on firm ground properly and all the temporary

adjustments should be made before taking the observations.

15. Iron and steel articles should be avoided near the compass.

16. The bubble should be checked before and after taking staff reading.

17. The tripod should not be disturbed by resting hands on it.

18. During high winds leveling work should be stopped.

19. The line of sight should be quite high above the ground.

20. Proper care should be taken in selecting change points.

21. The reading should be recorded properly and neatly.

22. The level should not be lifted by telescope.

23. The lenses should not be touched with hands.

24. The leveling screws should not be over tightened.

25. The level should be placed properly in the box.


xv Dept. of Civil Engineering Basic Surveying Practice Manual - 17CVL38

LIST OF EXPERIMENTS E

xp

erim

ent

No.

Date

of

Con

du

ctio

n

Experiments Page

No.

1 a) Measurements of distances using tape along with horizontal

planes and slopes, direct ranging.

b) Setting out perpendiculars. Use of cross staff, optical square

2 Obstacles in chaining and ranging – Chaining but not ranging,

ranging but not chaining, both ranging and chaining.

3 Measurements of bearings / directions using prismatic compass,

setting of geometrical figures using prismatic compass.

4 Measurement of bearings of sides of a closed traverse and

adjustment of closing error by Bowditch method.

5 Determination of distance between two inaccessible points using

compass and accessories

6 Determination of reduced levels of points using dumpy

level/auto level (simple leveling)

7 Determination of reduced levels of points using dumpy

level/auto level (differential leveling and inverted leveling)

8 To determine the difference in elevation between two points

using Reciprocal leveling and to determine the collimation error

9 To conduct profile leveling, cross sectioning and block leveling.

Plotting profile and cross sectioning in excel. Block contour on

graph paper to scale

10 Measurement of horizontal angle by repetition and reiteration

methods and Measurement of vertical angles using theodolite.

11 Determination of horizontal distance and vertical height to a base

inaccessible object using theodolite by single plane and double

plane method.

12 To determine distance and elevation using tachometric surveying

with horizontal and inclined line of sight.

13 Closed traverse surveying using Theodolite and applying

corrections for error of closure by transit rule.

14 Demonstration of Minor instruments Clinometer, Ceylon Ghat

tracer, Box sextant, Hand level, Planimeter, nautical sextant and

Pentagraph


xvi Dept. of Civil Engineering Basic Surveying Practice Manual - 17CVL38

IMPORTANCE OF BASIC SURVEYING PRACTICE

The planning and design of all Civil Engineering projects such as construction of

highways, bridges, tunnels, dams etc are based upon surveying measurements.

Moreover, during execution, project of any magnitude is constructed along the lines and

points established by surveying.

Thus, surveying is the basic requirement for all Civil Engineering projects.

Other principal works in which surveying is primarily utilized is;

To fix the national and state boundaries.

To chart coastlines, navigable streams and lakes.

To establish control points.

To execute hydrographic and oceanographic charting and mapping.

To prepare topographic map of land surface of the earth.


1 Dept. of Civil Engineering Basic Surveying Practice Manual - 17CVL38

EXPERIMENT 1-

a) Measurement of distances using tape along horizontal planes and slopes,

direct/indirect ranging,

b) Setting out perpendiculars. Use of cross staff, optical square.

Measurement of Distance

AIM: To measure distance between two points using tape bydirect ranging.

INSTRUMENTS REQUIRED

a) Chain or tape,

b) Ranging rods,

c) Arrows.

THEORY

The process of measuring the distance using chain or tape is called Chaining. While

measuring the length of a survey line, chain or tape must be stretched straight along the line

joining two terminal stations. When the length of the line exceeds the length of a tape, some

intermediate points will have to be established in line with the two terminal points before

chaining is started. This process of establishing such intermediate points is known as

Ranging. Direct ranging is done when two end points of the survey lines are intervisible. In

such cases ranging can either be done by eye or through some optical instrument such as line

ranger or a theodolite.

Fig.1.1: Direct Ranging

PROCEDURE

1.Let the length of a line AB is to be measured, Point ‘A’ being the starting point.

2.Erect two ranging rods vertically at ‘A’ and ‘B’.

3.The surveyor stands about half meter behind the ranging rod at ‘A’ in line with ‘AB’.

4.The assistant then goes with another ranging rod and establishes the rod at a point

approximately in line with ‘AB’ (by judgment) at a distance not greater than one chain

length from ‘A’.



Fig.1.2: Field conduction of Direct Ranging

5.The surveyor at ‘A’ directs the assistant to move the ranging rod till it is in line with

‘AB’. The code of signals used for this purpose is given in the table below:

SL.

NO.

Signal by the Surveyor

Action by the assistant

1 Rapid sweep with right hand Move considerably to the right

2 Slow sweep with right hand Move slowly to the right

3 Right arm extended Continue to move to the right

4 Right arm up and moved to the right Plumb the rod to the right

5 Rapid sweep with left hand Move considerably to the left

6 Slow sweep with left hand Move slowly to the left

7 Left arm extended Continue to move to the left

8 Left arm up and moved to the right Plumb the rod to the left

9 Both the hands above head and then brought down Correct

10 Both the arms extended forward horizontally and

the hands depressed briskly Fix the rod

6.Similarly establish some intermediate stations by direct ranging.

7.The follower stands at the point ‘A’ holding one end of the tape while the leader moves

ahead holding zero end of the tape in one hand and a bundle of arrows in the other. When

he reaches approximately one tape length distance from ‘A’, the follower directs him for

ranging in the line.



8.The tape is then pulled out and whipped gently to make sure that its entire length lies

along the line.

9.The leader then pushes the arrow into the ground, opposite the zero.

10.When the second arrow has been established by the leader, the follower picks up the

first arrow and both the persons move ahead as described in the step7, 8 and 9.

11.At the end of the line (at B) the last measurement will generally be a partial tape length.

The leader holds the zero end of the tape at ’B’ while the follower pulls the tape back till it

becomes taut and then reads against the arrow.

OBSERVATIONS & CALCULATIONS

Total distance measured = ………………….

Number of Paces = …………………………..

Pace value = =

RESULT:

Practical Application: (List any two practical scenario)



Measurement of Distance on Slopping Ground

Chaining on slopping ground

a) Direct method (Method of Stepping)

Fig.1.3: Measurement on Sloping Ground – Method of Stepping

1. Let it be required to measure the horizontal distance between the two points A and B.

2. The follower holds the zero end of the tape at A while the leader selects any suitable

length l1 of the tape and moves forward. The follower directs the leader for ranging.

3. The leader pulls the tape tight, makes it horizontal and the point 1 is then transferred to

the ground by a plumb bob. Sometimes, a special form of drop arrow is used to transfer

the point to the surface, as shown in figure above.

4. The procedure is then repeated. The total horizontal distance D between the two points

is then equal to l1+ l2+ l3+ l4+……….

5. The lengths l1, l2 etc., to be selected depend on the steepness of slope. Steeper the

slope, lesser the length and vice versa.



b) Indirect method

i. Angle measured

Fig.1.4: Clinometer

Fig.1.5: Indirect Method – Angle Method

1. Measure the inclined distances l1, l2 etc.

2. The slopes of the lines (𝜃1,𝜃2 etc.) with the help of clinometers.

3. The total horizontal distance D between the two points is then equal to ∑ 𝑙𝑖 cos 𝜃𝑖

ii. Difference in level measured

Fig.1.6: Indirect Method – Difference in Level Measured

1. The difference in the level (h) between the points is measured with the help of

levelling instrument.

2. The inclined length l is measured.

3. The total horizontal distance D between the two points is then equal to √ℎ2 + 𝑙2

RESULT:

Practical Application: (List any two practical scenario):



Settingout of Perpendiculars

AIM: To set out perpendiculars to a given chain line using cross staff, optical square and tape.

INSTRUMENTS REQUIRED:

a. Tape or chain

b. Ranging rods

c. Arrows

d. Cross staff

e. Optical square.

THEORY:

There are several types of instruments used to set out a right angle to a chain line. The

most common being cross staff, optical square and prism square. The simplest instrument

used for setting out right angle is a cross staff. It consists of either a frame or box with two

pairs of vertical slits and is mounted on a pole for fixing in the ground. The common forms of

cross staff areopen cross staff, French cross staff, and adjustable cross staff. Optical square

is somewhat more convenient and accurate instrument than the cross staff for setting out a line

at right angles to another line. It consists of a circular box with three slits at E, F, and G. in

line with the openings E and G, a glass silvered at the top and unsilvered at the bottom, is

fixed facing the opening E. Opposite to the opening F, a silver glass is fixed at A making an

angle of 45º to the previous glass. A ray from the ranging rod at Q passes through the lower

unsilvered portion of the mirror at B and is seen directly by eye at the slit E. Another ray from

the object at P is received by the mirror at A and is reflected towards the mirror at B which

reflects it towards the eye. Thus the images of P and Q are visible at B, if both the images are

in the same vertical line.

PROCEDURE:

I. Setting out perpendicular using Optical Square:

To set a right angle on a survey line, the instrument is held on the line with its centre

on the point at which perpendicular is erected. The slits F and G are directed towards

the ranging rod fixed at the end of the line. The surveyor (holding the instrument) then

directs person holding a ranging rod and standing in a direction roughly perpendicular

to the chain line, to move till the two images described above coincide.



Fig.1.7: Optical Square and field procedure to set out perpendicular

II. Setting out perpendicular using cross staff:

Fig.1.8: Cross staff

1. The cross staff is set up at a point on the line where perpendicular is to be set out.

2. The cross staff is turned until one line of sight bisects the ranging rod at the end of the

survey line.

3. The line of sight through the other slit will be at right angle to the survey line and

ranging rod may be established in that direction.

III. Setting out perpendicular using tape:

Fig.1.9: Methods of Setting Out Perpendiculars



Let it be required to erect a perpendicular to the chain line AB at a point C.

3-4-5 method

1. Establish a point E at a distance 3m from C.

2. Put the zero end of the tape at E and the 10m end at C. The 5m and 6m marks are

brought together to form a loop of 1m.

3. The tape is now stretched tight fastening the ends E and C. The point D is thus

established. CD will be perpendicular to AB.

Second method

1. Select E and F equidistance from C.

2. Hold the zero end of the tape at E and 10m end at F.

3. Pick up 5m mark, stretch the tape tight and establish D. Join DC.CD will be

perpendicular to AB.

To drop a perpendicular to a given chain line from a point outside it

1. Select any point E on the line AB.

2. With D as center and DE as radius, draw an arc to cut the chain line in F.

3. Bisect EF at C. CD will be perpendicular to AB.

RESULT: The perpendiculars are set out successively in the field.




EXPERIMENT 2- Obstacles in chaining and ranging – Chaining but not ranging, ranging

but not chaining, both ranging and chaining.

Obstacle to Ranging but Not Chaining

AIM: To range and measure the distance between two points which is having obstacle to

ranging but not chaining.


a. Chain or tape

b. Ranging rods

c. Arrows

d. Cross staff.

THEORY

There may be two cases of this obstacle.

a) Both ends of the line may be visible from intermediate points on the line – Reciprocal

ranging or indirect ranging.

Fig.2.1: Indirect Ranging – Reciprocal Ranging

b) Both ends of the line may not be visible from intermediate points on the line.



Fig.2.1: Indirect Ranging: When Both Ends Not Visible from Intermediate Points

PROCEDURE

1. Let AB be the line in which A and B are not visible from intermediate point on it.

2. Through A, draw a random line AB1in any convenientdirection but as nearly towards B

as possible.

3. The point B1should be chosen in such a way that it is visible from B and BB1 is

perpendicular to the random line. Measure BB1.

4. Select points C1and D1 on the random line and erect perpendicular C1C=𝐴𝐶1

𝐴𝐵1𝑋𝐵𝐵1 and

D1D= 𝐴𝐷1

𝐴𝐵1𝑋𝐵𝐵1on it.

Obstacle to Chaining but Not Ranging

AIM: To range and measure the distance between two points which is having obstacle to

chaining but not ranging.


a. Chain or tape

b. Ranging rods

c. Arrows

d. Cross staff

e. Optical square.

THEORY

There may be two cases of this obstacle:

a) When it is possible to chain round the obstacle, i.e. a pond, hedge etc.



b) When it is not possible to chain round the obstacle, i.e. a river.

PROCEDURE

A. When it is possible to chain round the obstacle

Method (a):

1. Select two points A and B on either side.

2. Set out equal perpendiculars AC and BD shown

in [fig. (a)]. Measure CD=AB.

Method (b):

1. Set out AC perpendicular to the chain line.

Measure AC and BC [fig.(b)]

2. The length AB is calculated from the relation

AB=√𝐵𝐶2 − 𝐴𝐶2.

Method (c):

1. By optical square or cross staff, find a point C

which subtends 90º with A and B.

2. Measure AC and BC [fig.(c)]. The length AB is

calculated from the relation AB=√𝐴𝐶2 + 𝐵𝐶2.

Method (d):

1.Select two points C and D on either side of A in the same

line.

2.Measure AC, AD, BC and BD [fig.(d)].

3.Let angle BCD be equal to 𝜃.

cos 𝜃= 𝐵𝐶2+𝐴𝐶2−𝐴𝐵2

2𝑋𝐵𝐶𝑋𝐴𝐶

4.The length AB is calculated from the relation



𝐴𝐵 = √(𝐵𝐶2𝑋𝐴𝐷)+(𝐵𝐷2𝑋𝐴𝐶)

𝐶𝐷− (𝐴𝐶𝑋𝐴𝐷)

Method (e):

1. Select any point E and range C in line with AE,

making AE= EC.

2. Range D in line with BE and make BE=ED.

Measure CD=AB [fig.(e)].

Method (f):

1. Select any suitable point E and measure AE and BE.

Mark C and D on AE and BE such that CE=𝐴𝐸

𝑛 and DE =

𝐵𝐸

𝑛 .

2. Measure CD. AB= n XCD [fig.(f)].

B. When it is not possible to chain round the obstacle

Method (a):

1. Select point B on one side and A and C on the other

side. Erect AD and CE as perpendiculars to AB and range B, D and

E in one line.

2. Measure AC, AD and CE [fig.(a)].

3. If a line DF is drawn parallel to AB, cutting CE in F

perpendicularly. The triangles ABD and FDE will be similar.

𝐴𝐵 =𝐴𝐶𝑋𝐴𝐷

𝐶𝐸 − 𝐴𝐷

Method (b):

1.Erect a perpendicular AC and bisect it at D.

2.Erect perpendicular CE at C and range E in line with BD.

3.Measure CE =AB [fig.(b)].



Method (c):

1.Erect a perpendicular AC at A and choose any convenient point C.

2. With the help of an optical square, fix a point D on the chain line in

such a way that BCD is a right angle [fig.(c)].

3.Measure AC and AD.

4.The triangles ABC and DAC will be similar.

𝐴𝐵 =𝐴𝐶2

𝐴𝐷

Method (d):

1.Fix point C in such a way that it subtends 90º with AB.

2.Range D in line with AC and make AD=AC.

3.At D, erect a perpendicular DE to cut the line in E [fig.(d)].

Then AB=AE.

Obstacle to Both Chaining and Ranging

AIM: To range and measure the distance between two points which is having obstacle to both

chaining and ranging.


a. Chain or tape

b. Ranging rods

c. Arrows

d. Cross staff.

THEORY:

A building is the typical example of this type of obstacle. The problem lies in

prolonging the line beyond the obstacle and determining the distance across it.



PROCEDURE

Method (a):

1.Choose two points A and B to one side and erect

perpendiculars AC and BD of equal length.

2.Join CD and prolong it. Choose two points E and F on CD

and erect perpendiculars EG and FH equal to that of AC.

3.Join GH and prolong it. Measure DE=BG [fig.(a)].

Method (b):

1.Select a point A and erect a perpendicular AC of any

convenient length.

2.Select another point B on the chain line such that

AB=AC. Join B and C and prolong it to any convenient

point D. At D set right angle DE such that DE=DB.

3.Choose another point F on DE such that DE=DC.

With F as centre and AB as radius, draw an arc. With E as centre, draw another arc of

same radius to cut the previous arc in G.

4.Join GE which will be in range with the chain line. Measure CF. the AG=CF [fig.(b)].

Method (c):

1. Select two points A and B on the chain line and construct an

equilateral triangle ABE by swinging arcs. Join AE and produce it

to any point F.

2. On AF, choose any point H and construct an equilateral

triangle FHK.

3. Join F and K and produce it to D such that FD=FA.

4. Choose a point G on FD and construct an equilateral triangle CDG.

5. The direction CD is in range with the chain line [fig.(c)].

6. The length BC is given by

BC=AD-AB-CD=AF-AB-CD



Method (d):

1.Select two points A and B on the chain line and set a

line CBD at any angle.

2.Join A and C and produce it to F such that AF

=nXAC.

3.Similarly join A and D and produce it to G such that

AG= nXAD.

4.Join F and G and mark point E on it such that

FE=nXBC.

5.Similarly, produce AF and AG to H and K respectively such that AH=nlXAC and AK=

nlXAD.

6.Join H and K and mark J on it in such a way that HJ= nlXCB.

7.Join EJ, which be in range with chain line.

8.The obstructed distance BE [fig.(d)].is given by

BE= (n-1)AB

OBSERVATIONS & CALCULATIONS:

A. When it is possible to chain round the obstacle

Method (a):

Method (b):

Method (c):

Method (d):

Method (e):

Method (f):

B. When it is not possible to chain round the obstacle

Method (a):



Method (b):

Method (c):

Method (d):

RESULT: The distance between two points is found to be = ________ m.



EXPERIMENT 3- Measurement of bearings/directions using prismatic compass, setting of

geometrical figures using prismatic compass.

CASE 1: RECTANGLE/SQUARE

AIM: To set out a regular rectangle of side AB=20m and BC=15m using compass and chain

given the bearing of AB is α = 68030’

APPARATUS:

a) Prismatic compass,

b) ranging rods,

c) arrows,

d) Tape etc.

THEORY: The included angle of geometrical figure is given by the angle

θ = [2n-4]*90o/n

θ = included angle

θ = [2*4-4]*90o/4

θ = 90 o

Line Fore Bearing Back Bearing Length

AB 68030’ 248030’ 30

BC 338030’ 158030’ 20

CD 248030’ 68030’ 30

DA 158030’ 338030’ 20

PROCEDURE:

1) With the given bearing of AB = 68030’ and the condition that the angles of a rectangle

are equal to 900, the bearings of the sides BC, CD and DA are computed and entered in

the table shown.

2) In the field, a station A is selected and the compass is setup over A. after centering and

levelling, the bearing of 68030’ is set on the compass.Thus, the direction of the line AB

is obtained and a ranging rod is fixed in that direction.

3) From A, a distance of 30 m is measured and station B is marked.

4) The compass is shifted to B and after centering and levelling. The station A is

observed to check the BB of the line AB which should be equal to 248030’.



5) The bearing of the next line BC, 338030’ is set on the compass and the direction of the

line BC is obtained and a ranging rod is fixed at a convenient distance.

6) From B a distance of 20 m is measured along this direction and station C is marked on

the ground.

7) Steps 4, 5 and 6 is repeted to set the remaining points on the ground.

Fig.3.1: Setting up of Rectangle

Observation and Calculation:

Given that,

Bearing of AB = --------

Assuming traversing is done in anticlockwise direction.

We have,

a) Bearing of BC= BB of AB+ Included angle = -----------

b) Bearing of CD = BB of BC + Included angle = -----------

c) Bearing of DA = BB of CD + Included angle= -----------

Check:Bearing of AB= BB of DA + Included angle = -----------

Theoretical Parameters:Sides AB+BC+CD+DA = ------m

Practical Parameters:Sides AB+BC+CD+DA =-------m

% of error in DC= Theoretical value –Practical value X100 = -------%

Theoretical value

RESULT:A rectangle of sides 15m & 20m is constructed by using a prismatic compass.

The linear error is -----------m &Angular error is -------------

20 m 30 m

B

A

C

D



CASE 2: PENTAGON

AIM: Construct a regular pentagon of side AB=6m using compass

APPARANTIS:

a) Prismatic Compass,

b) Ranging rod,

c) Arrows,

d) Tape.

PROBLEM: To construct a regular pentagon ABCDE taking the length of side as 6m &

bearing of AB as 30o30’.

THEORY: The included angle of any geometrical figure is given by

θ = [2n-4]*90o/n

Where n = No of sides.

θ = Included angle.

θ = [2*5-4]*90o/5

θ = 108 o

PROCEDURE:

1) Set out the compass at station A & make temporary adjustments. The line of sight is

turned to set the bearing as 30o30’ long, this line of sight mark a point B at a distance of

6m.

2) Shift the compass to point B and make the temporary adjustments. The back bearing of

AB is noted as a check the line of sight is turned to set the bearing of line BC along the

line of sight mark a point C along a distance of 6m.

3) Now the compass is shifted to point c to set the bearing of line as 174o 30’along this

line of sight mark a point D at a distance of 6m.

4) Now the compass is shifted to point C, to set the bearing of line as 174o30’along this

line of sight mark a point D at a distance of 6m.

5) The same procedure is repeated at a corresponding points D&E & corresponding

bearings are locked and the points are marked as check, measure the distance of EA.



Fig.3.2: Setting up of Pentagon

OBSERVATION AND CALCULATION

Interior angle of Pentagon,

I.A = θ = [2n-4]*90o/nI.A = ---------------

Assuming traversing is done in clockwise direction.

We have,

a) FB of line AB= ---------- B.B of line AB = -----------

b) FB of line BC = BB of line AB – Interior angle =-------------

B.B of line BC = -----------

c) FB of line CD = BB of line BC – Interior angle=-------------

B.B of line CD = -----------

d) FB of line DE = BB of line CD – Interior angle =-------------

B.B of line DE = -----------

e) FB of line EA = BB of line DE – Interior angle=-------------

B.B of line EA = -----------

Check:FB of line AB = BB of line EA – Interior angle =-------------

Line Fore Bearing Back Bearing Length obtained

Std Obtained

AB

BC

CD

DA

EA



RESULT: A regular pentagon of side 6m is constructed using a prismatic compass.

Linear Error Is ------M

Angular Error Is -----M

CASE 3: HEXAGON

AIM: Construct a regular hexagon of side AB=6m with the FB of AB is N30oE.

APPARATUS:

a) prismatic compass,

b) ranging rod,

c) arrows,

d) tape etc.,

THEORY: The included angle of any geometrical figure is give by

θ = [2n-4]*90o/n

Where n = no of sides,

θ = included angle

θ = [2*6-4]*90o/6

θ = 120 o

PROCEDURE:

Exterior angle =360-120=240o Included angle=120o.

1) Set out the compass at station A & make temporary adjustments. The line of sight is

turned to set the bearing as 30o along this line of sight mark a point B at a distance of 6m.

2) Shift the compass to point B and make the temporary adjustments. The back bearing of

AB is noted as a check, the line of sight is turned, to set the bearing of line BC along the

line of sight mark a point C at a distance of 6m.

3) Now the compass is shifted to point C, to set the bearing of line as 150o, along this line

of sight mark a point D at a distance of 6m.

4) The same procedure is repeated at a corresponding points D, E&F, corresponding

bearings are located and the points are marked, as a check measure the distance of FA.

OBSERVATION AND CALCULATION

Interior angle of Pentagon,

I.A = θ = [2n-4]*90o/nI.A = ---------------

Assuming traversing is done in clockwise direction.

We have,



1. FB of line AB= ---------- B.B of line AB = -----------

2. FB of line BC = BB of line AB – Interior angle =-------------

B.B of line BC = -----------

3. FB of line CD = BB of line BC – Interior angle =-------------

B.B of line CD = -----------

4. FB of line DE = BB of line CD – Interior angle =-------------

B.B of line DE = -----------

5. FB of line EF = BB of line DE – Interior angle =-------------

B.B of line EF = -----------

6. FB of line FA = BB of line EF – Interior angle =-------------

B.B of line FA = -----------

Check:

7. FB of line AB = BB of line FA – Interior angle.

=-------------

Line Fore Bearing Back Bearing Length obtained

Std Obtained

AB

BC

CD

DA

EA

FA

RESULT: Thus a regular hexagon of sides 6m is constructed using compass.

Linear error is ------m

Angular error is -------

EXPERIMENT 4- Measurement of bearings of sides of a closed traverse and adjustment of

closing error by Bowditch method.



AIM: To measure the bearings of the sides of the closed traverse and adjustment of the

closing error by Bowditch method.


a. Prismatic compass with stand

b. Chain/tape

c. Ranging rods

d. Arrows.

THEORY:

A ‘traverse’ is a frame formed by a series of connected straight lines, none of which is

connected at each of its ends to lines more than one. The points defining the ends of the

traverse line are called traverse stations or traverse points. When the lines form a circuit which

ends at the starting point is known as a closed traverse. If the circuit ends elsewhere, it is said

to be an open traverse. Closed traverse is suitable for locating boundaries of lakes, forests

etc. Open traverse is suitable for surveying along long narrow strip of land required for a road

or canal or pipeline or the coast line.

In compass traversing, the magnetic bearing of the survey lines are measured by a

compass and the length of the survey lines are measured either with a chain or with a tape.

The direction of magnetic meridian is established at each traverse station independently. The

method is also known as free or loose needle method. The latitude (L) of survey line may be

defined as its coordinate length measured parallel to the assumed meridian direction. The

latitude of the line is positive when measured northward (upward) and is termed as northing.

The latitude of the line is negative when measured southward (downward) and is termed as

southing.Thedeparture (D) of survey line may be defined as its coordinate length measured

right angles to the assumed meridian direction. The departure of the line is positive when

measured eastward and is termed as easting. The departure of the line is negative when

measured westward and is termed as westing.

Closing error or error of closure is the actual distance by which the traverse fails to

close. Bowditch method is also known as compass rule. In this method the total error in

latitude and departure is distributed in proportion to the lengths of the traverse lines. It is used

to balance the traverse when the angular and linear measurements are equally precise. Transit

method may be employed to balance the traverse when the angular measurements are more



precise than the linear measurements. In this method the total error in latitude and departure is

distributed in proportion to the latitude and departure of the traverse lines.

Fig.4.1: Closing Error

FORMULAE

Bowditch method:

CL= ∑𝑳𝑿𝒍

∑ 𝒍

CD= ∑𝑫𝑿𝒍

∑ 𝒍

Where CL= Correction to latitude of any side

CD= Correction to departure of any side

𝑙= Length of that side

∑ 𝑙= Perimeter of traverse

∑ 𝐿= Total error in latitude

∑ 𝐷= Total error in departure

PROCEDURE:

1. Let A, B, C, D, E are the traverse stations.

2. Set the compass at station ‘A’ and take the fore bearing of the line AB. Measure the

distance AB.

3. Now shift the instrument to the station ‘B’, take the bearing of the line BC. Also tale

the back bearing of line AB, measure the distance BC.

4. Similarly the length and bearing of each line of the traverse is to be measured.




Bowditch method

SL.

NO.

Line Length

(𝑙)in m

Bearing Latitude

L=𝑙𝐶𝑜𝑠𝜃

Departure

D=𝑙𝑆𝑖𝑛𝜃

Corrections Corrected

Latitude Departure Latitude Departure

1

2

3

4

5

6

∑ 𝑙= …………….∑ 𝐿= ……………

∑ 𝐷= ……………

RESULT:




EXPERIMENT5 - Determination of distance between two inaccessible points using

compass and accessories

AIM: To find the distance between two inaccessible points using Compass, Tape etc.

APPARATUS:

a. Tape

b. Arrows

c. Prismatic Compass with stand.

THEORY: The method is based on the trigonometric proposition of

i. Sine rule: That, if one side and three angles of a triangle are known then, the third

side of a triangle can be calculated.

ii. Cosine rule: that, if two sides of a triangle and included angle between them is

known, then the third side of a triangle can be calculated.

Thus, on a known base length CD, the directions of two inaccessible points A and B are

observed by Prismatic compass from two stations C and D. The angle between the lines CA,

CB, CD and DA, DB, DC is then computed and using rule (i) and (ii), the inaccessible

distance AB can be calculated.

Fig.5.1: Measurement of Distance between Inaccessible Points

PROCEDURE:

1. Let A and B be the two inaccessible points between which the distance is to be

determined.

2. Select two points C and D at a known distance from each other



3. Now take the instrument at station C and take the bearings to the points A, B, and D.

4. Shift the instrument to point D and take the bearing of points A, B, C.

5. The angles 1, 2, 3, 4and α and β are calculated as shown in calculation part and

the distance between A and B is calculated.

Observations:

SI No Instrument @ Side Bearing

1 C

CA

CB

CD

2 D

DC

DA

DB

Calculations:

Angle 1 = Fore bearing of CB - Fore bearing of CA

Angle 2 = Fore Bearing of CD - Fore Bearing of CB

Similarly Calculate

3 = Fore bearing of DA - Fore bearing of DC

4 = Fore bearing of DB - Fore bearing of DA

Consider Triangle ACD

∠CAD = α = 180 – (1 + 2 + 3)

Applying Sine rule:

𝐶𝐷

𝑠𝑖𝑛𝛼=

𝐴𝐶

𝑠𝑖𝑛𝜃3=

𝐴𝐷

sin( 𝜃1 + 𝜃2)

a) 𝐴𝐶 =𝐶𝐷 𝑠𝑖𝑛𝜃3

𝑠𝑖𝑛𝛼



b) 𝐴𝐷 =𝐶𝐷 sin(𝜃1+𝜃2)

𝑠𝑖𝑛𝛼

Consider Triangle BCD

∠CBD= = 180 - ((2+3+4)

Applying Sine Rule:

𝐶𝐷

𝑠𝑖𝑛𝛽=

𝐵𝐷

𝑠𝑖𝑛𝜃2=

𝐶𝐵

sin( 𝜃3 + 𝜃4)

a) 𝐶𝐵 =𝐶𝐷 sin(𝜃3+𝜃4)

𝑠𝑖𝑛𝛽

b) 𝐵𝐷 =𝐶𝐷 𝑠𝑖𝑛𝜃2

𝑠𝑖𝑛𝛽

Considering Triangle ACB

Applying Cosine Rule

𝐴𝐵 = √(𝐴𝐶2 + 𝐵𝐶2 − 2 × 𝐴𝐶 × 𝐵𝐶 × 𝑐𝑜𝑠𝜃1)

Considering Triangle ADB

Applying Cosine Rule

𝐴𝐵 = √(𝐴𝐷2 + 𝐵𝐷2 − 2 × 𝐴𝐷 × 𝐵𝐷 × 𝑐𝑜𝑠𝜃4)

Results: The distance between two inaccessible points = ________M





(simple leveling).

AIM: To find the difference in elevation or level between any two points by using the single

set up of the instruments.


a. Dumpy level with tripod

b. Leveling staff.

THEORY: When the difference of level between two points is determined by setting the

leveling instrument midway between the points, the process is called simple leveling.

PROCEDURE:

Fig.6.1: Simple Leveling

1. Let A&B are two points whose difference of level in to be determined.

2. Setup the instrument at ‘O’ approximately almost midway between the point A&B,

leveling by proper temporary adjustments.

3. Direct the telescope towards the staff held on a point A and make the corresponding

staff reading & record directly.

4. Hold the staff on a next point B and take the reading and enter in the field book.

5. The difference of these readings gives the difference of level between A&B



Observation and Calculation

Station B.S I.S F.S H.I R.L Remarks

B.M

A

B

Check:

∑BS-∑FS = Last RL – First RL.

RESULTS: The difference in elevation between two points A & B is_________M





(differential leveling and inverted leveling).

AIM: To find the difference in elevation between any two points which are situated at some

distance apart by collimation system or H.I method.

APPARATUS:

a. Dumpy level with tripod

b. Leveling staff.

OBJECTIVE: The main object of differential leveling to determine the elevation between

the points when,

1. The points are a great distance apart.

2. The difference of elevation between the points is large.

3. There are obstacles between the points.

This method in also known as compound leveling or continuous leveling. In the method,

the level in setup at several suitable positions and staff reading are taken at all of these.

THEORY:

In this method the height of the instrument is found out by adding the back sight

reading to the R.L of the B.M on which the B.S is taken. Then the R.L of the intermediate

points and the change point are obtained by subtracting the respective staff reading from the

H.I.

Fig.7.1: Differential Levelling- When points are far apart



Fig.7.2: Differential Levelling – Points with large difference of elevation

Fig.7.3: Differential Levelling – Points Having Obstacles In Between

PROCEDURE:

1. Let A&B be the two points whose difference of level is required to find.

2. Set up the instrument at point ’O1’ and after doing proper temporary adjustments

take back sight reading on a bench mark.

3. Find the height of instrument by adding B.S reading to the bench mark.

4. Take staff reading on the intermediate point like C D E &F etc.

5. Now change the instrument to the point O2 and make temporary adjustments.

6. Take the B.S reading at E& find the new H.I.

7. Take the staff reading on point F,G etc., and repeat the procedure to reach the

point ‘B’

OBSERVATION AND CALCULATION – HEIGHT OF INSTRUMENT METHOD

Station BS IS FS HI RL Remarks

B.M



A

B

∑BS= ∑FS=

Check:


RESULT: The difference in elevation between two points A & B is ----------------M




OBSERVATION AND CALCULATION – RISE AND FALL METHOD

Station BS IS FS Rise Fall RL Remarks

B.M

A

B

∑BS= ∑FS=

Check:

∑BS-∑FS =∑Rise-∑Fall= Last RL – First RL.

RESULT:



Determination of RL of an object above the plane of collimation using inverted leveling.

AIM:To determine the RL of a point which is above the horizontal line of sight?

PROCEDURE:

1. Let B be the point whose level is to be determined.

2. Setup the instrument at ‘O’ and the instrument is levelled by temporary adjustments.

3. Direct the telescope towards the bench mark (A) and note the corresponding staff

reading

4. Hold the staff in inverted position at point B and note the corresponding staff reading.

Fig.7.4: Inverted Levelling

Station B.S F.S H.I R.L Remarks

1 BM

2 Point B

Check:


RESULTS: The RL ofB is __________ M




EXPERIMENT 8 - To determine the difference in elevation between using reciprocal

leveling and to determine the collimation error

AIM:To determine the difference in elevation between two points using Reciprocal Leveling

and determination of Collimation Error

APPARATUS:

a. Dumpy Level with stand

b. Leveling Staff

c. Arrow's

d. Ranging rods.

THEORY: When it is necessary to carry leveling across a river, ravine or any Obstacle

requiring a long sight distance between two points so situated that no place for level can be

found from which the length of foresight and back sight will be even approximately equal,

special method i.e., reciprocal leveling is used to obtain accuracy and to eliminate the

following. (1) Error in instrument adjustment; (2) Combined effect of earth's curvature and

refraction of the atmosphere and (3) Variation in the average refraction.

Fig.8.1: Reciprocal Levelling



PROCEDURE:

a) Let A and B be the two points on opposite banks of the river whose difference in

elevation is to be determined,

b) Set up the instrument very near to A and with the bubble central take readings on the

staff held at A and B, say a1 and b1 respectively.

c) Transfer the instrument to B and set it up very near to B.

d) With the bubble in the central, note down the staff readings on the staff at A and B,

say a2 and b2 respectively,

e) Calculate the true difference in elevation between two points and the collimation

error as given below.

Observations:

Instrument

At Staff reading at A Staff Reading at B

A a1 = b1 =

B a2 = b2 =

Specimen Calculation:

We have

D = (b1-e)-a1 ------- (1)

D= (b2-a2) f e ------ (2)

Adding (1) and (2)

D = (1/2 ) {(b1 – a1) + (b2 – a2)}

D is the difference in Elevation

Equating (1) and (2)

e= (1/2) {(b1 - a1) - (b2 - a2)} e is the collimation error

Results:




EXPERIMENT 9 -To conduct profile leveling, cross sectioning and block leveling.

Plotting profile and cross sectioning in excel. Block contour on graph paper to scale

Profile Levelling

AIM: To conduct profile leveling for water supply / sewage line and to draw the longitudinal

section to determine the depth of cut and depth of filling for a given formation level.

INSTRUMENTS USED:

a. Dumpy level with tripod,

b. Prismatic compass,

c. Chain,

d. Tape,

e. Ranging rods,

f. Arrow pins,

g. Leveling staff.

THEORY: Profile leveling is the process of determining the elevations of points along a

fixed line such as center line of a railway, highway, canal, water supply and sewer. The fixed

line may be a single straight line or a series of straight lines connected by curves. It is also

known as longitudinal sectioning. By means of such sections it is possible to study the

relationship between the existing ground surface and the levels of the proposed construction

in the direction of its length. The profile is usually plotted on specially prepared profile

paper, on which the vertical scale is much larger than the horizontal, and on this profile,

various studies relating to the fixing of grades or formation lines and the estimation of

depths, volume of earthwork and estimating of costs are made.



Fig.9.1: Profile Levelling

PROCEDURE:

1. Fix the center line alignment for the project under consideration.

2. Mark the points on this alignment at regular intervals by means of arrow pins.

3. Note down the bearings of each section of line by setting the prismatic compass at

each of the turning points.

4. Set up the Dumpy level to one side of the profile line and note down the BS reading

by holding the staff on the nearby B.M and calculates the Hl for the first station.

5. Hold the staff at each of the point marked on the profile line and note down the I.S.

6. When the readings on the staff are not very clear, note down the staff reading FS. By

holding the staff on a permanent point.

7. Shift the instrument and set it further equalizing the length of F.S. and BS and then

note down the BS

8. Repeat the procedure from step (4) onwards till the end of the profile line.



Observation and Calculation

In

st. S

t.

Dis

tan

ce

BS

IS

FS

H.I

R.L

rem

ark

s

B.M. R.L. of

B.M.

A

Check:


RESULTS:




Cross Sectioning

AIM: To conduct cross sectioning to know the nature of the ground across the center line of

any alignment.

INSTRUMENTS USED:

a. Dumpy level with tripod,

b. Prismatic compass,

c. Chain,

d. Tape,

e. Ranging rods,

f. Arrow pins,

g. Leveling staff.

THEORY: it is the operation of leveling to determine the elevation of the points at right

angles on either sides of the center line of the proposed route. This is done to find out the

vertical sections of the surface of the earth on the ground. Cross section leveling helps in

computing the quantity of earthwork. The cross sections are plotted in the same manner as

longitudinal sections except that both the horizontal and vertical measurement is plotted to

the same scale.

Fig.9.2: Cross-Sectioning

PROCEDURE:

1. Fix the center line alignment for the project under consideration.

2. Mark the points on this alignment at regular intervals by means of arrow pins.

3. Note down the bearings of each section of line by setting the prismatic compass at

each of the turning points.



4. Set up the Dumpy level to one side of the profile line and note down the BS reading

by holding the staff on the nearby B.M and calculates the Hl for the first station.

5. Hold the staff at each of the point marked on the profile line and note down the I.S.

6. Cross sections are taken at regular intervals (such as 0,5,10,15,20……) along the

alignment.

7. When the readings on the staff are not very clear, note down the staff reading FS. By

holding the staff on a permanent point.

8. Shift the instrument and set it further equalizing the length of F.S. and BS and then

note down the BS

9. Repeat the procedure from step (4) onwards till the end of the profile line.



OBSERVATIONS AND CALCULATIONS

Inst

. S

t.

Distance

BS

IS

FS

H.I

R.L

rem

ark

s

L C R

B.M.

A 0

Cross

sectioning

at 0 meter

chainage

L1

L2

R1

R2

B 10

Cross

sectioning

at 10

meter

chainage

L1

L2

R1

R2

C 20

Cross

sectioning

at 20

meter

chainage

L1

L2

R1

R2

CHECK

Check:

∑BS-∑FS = Last RL – First RL

RESULT:




Block leveling, preparation of contour plan using excel. Use of planimeter/graph and

computations of Areas and volumes.

Block Levelling

AIM: To conduct Block leveling at the required place.


a. Dumpy level with tripod stand

b. Levelling staff

c. Measuring tape

d. Chain

e. Arrows

f. Ranging rods.

THEORY:

This method is used when the area to be surveyed is small and the ground is not very

much undulated. The area to be surveyed is divided into a number of squares. The size of the

square may vary from 5-20m depending upon the nature of the contour and contour interval.

The contour lines may then be drawn by interpolation. It is not necessary that the squares

may be of the same size. Block levelling is also known as spot levelling.

PROCEDURE

Fig.9.3: Block Levelling – Perspective View



Fig.9.4: Block Levelling - Plotting

1.The dumpy level is placed at suitable positions so that all the points on the block are

visible and after temporary adjustment the staff readings are taken.

2.The first staff reading of any set up is entered in the BS column and the last in the FS

column. The other readings are entered in the IS column.

3.Prepare a grid of blocks at regular intervals.

4.Note down the staff reading on each intersecting points of the block.

5.Draw the block diagram and the contours from the calculated RL’s.


BS IS FS HI RL Distance Station Remarks

RESULT



The block leveling has been carried out on the given profile of the ground for suitable

size of the block.

Contouring

AIM: To calculate the area and volume of the obtained contours of particular work.

THEORY: Contour is an imaginary line on the ground joining the points of equal elevation.

It is a line in which the surface of the ground is intersected by a level surface.


The Area of the contours can be calculated by using digital Planimeter.

The Volume of the contours can be calculated by using Trapezoidal and Prismoidal

formula.

Prismoidal formula:

V = 𝑑

3 [(𝐴1 + 𝐴𝑛) + 4 (𝐴2 + 𝐴4 … … … 𝐴𝑛 − 1) + 2(𝐴3 + 𝐴5 … … . 𝐴𝑛 − 2)]

Trapezoidal formula:

V = d [(𝐴1+𝐴2)

2+ 𝐴2 + 𝐴3 + ⋯ … … + 𝐴𝑛 − 1]



EXPERIMENT 10- Measurement of horizontal angle by repetition and reiteration

methods and measurement of vertical angles using theodolite

Method of Repetition

AIM: To determine the horizontal angle between two points by method of Repetition

INSTRUMENTS AND ACCESSORIES:

a. Transit Theodolite

b. Ranging Rod -02 No’s

c. Tripod stand

d. pegs-01 No

THEORY: The repetition method of measuring horizontal angles is adopted for survey

works of high accuracy. Also this method eliminates a large number of instrumental errors.

The following errors can be eliminated.

(i) Averaging both the verniers eliminates the error due to the eccentricity of the

verniers.

(ii) Averaging face left and face right observations eliminates collimination error and

trunnion axis error.

(iii) Errors of bisection are minimized taking a large number of observations.

(iv) Errors of graduations are eliminated by reading the angle on different parts of the

circle.

PROCEDURE:

Fig.10.1: Method of Repetition

With reference to the Figure, the procedure to measure angle AOB shall be as follows

1. Set the instrument on the station and make the temporary adjustment.



2. With both the clamps released the lower plate reading is brought to nearly 0o, the

upper clamp is then tightened and the reading is made precisely 0o 0’0” by using the

upper tangent screw.

3. Release the lower clamp and swing the telescope until the left-hand station (‘A’) is

approximately sighted, tighten the lower tangent screw. The exact bisection should be

achieved through the lower tangent screw.

4. Unclamp the upper clamp. Swing the telescope in clockwise direction, until the

second station (‘B’) is sighted, tighten the upper clamp. Bisect the station exactly

with the help of the upper tangent screw. The lower plate reading will give the

horizontal angle.

5. Release the lower clamp and once again bisect the left-hand station (‘A’) exactly.

6. Unclamp the upper clamp. Swing the telescope in clockwise direction, until the

second station (‘B’) is sighted accurately. This completes two repetitions and the

lower plate reading now gives double horizontal angle.

7. The procedure (steps 5 and 6) is repeated three to six times, depending upon the

accuracy required.

8. Note the readings against vernier A& vernier B, and the mean horizontal angle is

obtained.

9. Change the face of the instrument and repeat the above procedure (steps 2 to 7).

10. The average of the two face observations gives the required horizontal angle.



Instrument

Stn

Object

Stn

Face:LEFT Swing: RIGHT

Vernier ‘A’ Vernier ‘B’ Vernier Mean

No of

Repetition

Horizontal

Angle

o ‘ “ ‘ “ o ‘ “ o ‘ “

O

A

1 B

A

2 B

A

3 B

Instrument

Stn

Object

Stn

Face:RIGHT Swing: LEFT

Vernier ‘A’ Vernier ‘B’ Vernier Mean

No of

Repetition

Horizontal

Angle

o ‘ “ ‘ “ o ‘ “ o ‘ “

O

A

1 B

A

2 B

A

3 B



Position

of

Vertical

Circle

Trial

No.

Horizontal

Angle

Average

Horizontal

Angle

o ‘ “

Face

Left

1

2

3

Face

Right

1

2

3

Average horizontal angle

RESULTS: The horizontal angle after 03 repetitions each on face left and face right is =

AOB = o “ ‘




Measurement of Horizontal Angle-Method of Reiteration

AIM: To Determine the Horizontal Angle between More than Two Points by Method of

Reiteration

INSTRUMENT AND ACCESSORIES:

a. Transit Theodolite

b. Ranging Rod-04 No’s

c. Tripod stand

d. Pegs-01

THEORY: When more than one angle is to be measured at a station, the reiteration

method of measuring horizontal angles is adopted. This method enhances the accuracy of

measurement. Also this method eliminates certain instrumental errors. The following are

the errors that can be eliminated.

(i) Errors of graduations is eliminated by reading the angle on different parts of

the circle

(ii) The closing error can be checked

PROCEDURE:

Fig.10.2: Method of Reitiration

With reference to the Figure, the procedure to measure the angles AOB, BOC, COD and

DOA shall be as follows:

1. Set the instrument on the station and make the temporary adjustments.

2. With both the clamps released the lower plate reading is brought to nearly 0o the

upper clamp is then tightened and the reading is made precisely 0o 0’0” by using the

upper tangent screw.



3. Release the lower clamp and swing the telescope until the first station (‘A’) is

approximately sighted, tighten the lower tangent screw. The exact bisection should be

achieved through the lower tangent screw.

4. Unclamp the upper clamp, Swing the telescope in clockwise direction, until the

second station (‘B’) is sighted, tighten the upper clamp. Bisect the station exactly with

the help of the upper tangent screw.

5. Note down the vernier readings, the difference in the vernier readings will give the

angle AOB.

6. Release the upper clamp and bisect the next station (‘C’) precisely using the upper

clamp and tangent screw.

7. Note down the vernier readings, the difference in the vernier readings will give the

angle BOC.

8. Repeat the procedure (step 6 and 7) so as to bisect station ‘D’ and obtain angle

COD.

9. From the last station (‘D’) close the work b sighting the first station (‘A’).

10. Note the vernier reading and check whether it is within permissible limits and

obtain the corrected angles.

11. Change the face of the instrument and repeat the above procedure (steps 2 to 7).

12. The average of the two face observations gives the required horizontal angle.



Insrument

Stn

Object

Stn

Face : Left

Swing : Right

Ver ‘A’ Ver ‘B’ Vernier Mean

Horizontal

Angle o ‘ “ ‘ “ o ‘ “ o ‘ “

O

A AOB=

B BOC=

C COD=

D DOA=

A

Insrument

Stn

Object

Stn

Face : Right

Swing : Left

Ver ‘A’ Ver ‘B’ Vernier Mean

Horizontal

Angle o ‘ “ ‘ “ o ‘ “ o ‘ “

O

A AOB=

B BOC=

C COD=

D DOA=

A

RESULT: The average angles obtained by the method of Reiteration are as follows:

AOB= COD=

BOC= DOA=



Measurement of vertical angles using theodolite.

AIM: To Measure The Vertical Angle Of The Object ‘A’ Shown With Respect To The

Station O.

APPARATUS:

a. Theodolite

b. ranging rods

c. Tape

THEORY: A Vertical is the angle which the inclined line of right to an object makes with

the horizontal. The vertical angle is the angle of elevation when the line of sight is inclined

upwards from the horizontal line. It is the angle of depression when the line of sight is

inclined downward from the horizontal line.

PROCEDURE:

Fig.10.3: Vertical Angle Measurement

1) Set up the theodolite over the station O and level it accurately with reference to the

altitude bubble.

2) Set the zero of the vernier ‘C’ exactly to the zero of the vertical circle by means of

the vertical circle clamp and tangent screw.

3) Bring the bubble of the altitude level to center of its run by means of clip screw the

line of collimation is the made horizontal which vernier reads zero.



4) Loosen the vertical circle clamp and direct the telescope towards the object A,

clamp the vertical circle clamp. Bisect A exactly by turning the tangent screw.

5) Read both the verniers C&D the mean of the two readings given the value of the

required angle.

6) Change the face of the instrument and repeat the same procedure. The mean of the

two vernier readings given the second value of the required angles.

7) The average of the two values thus obtained given the value of the required vertical

angle.



OBSERVATIONS

1. Measurement of Vertical Angles

Instrument

Stn

Point

Sighted

Face : Left Swing :

Right

Ver ‘C’ Ver ‘D’ Vernier Mean Vertical Angle

o ‘ “ ‘ “ o ‘ “ o ‘ “

O A

Insrument

Stn

Point

Sighted

Face :Right Swing

: Left


o ‘ “ ‘ “ o ‘ “ o ‘ “

O A

RESULT:

Vertical angle = o



EXPERIMENT 11-Determination of horizontal distance and vertical height to a

base inaccessible object using theodolite by single plane and double plane method.

Elevation of an Inaccessible Object by Single Plane Method.

AIM: To determine the reduced level of an elevated object whose base is inaccessible

from the instrument station.


a) Transit Theodolite with accessories

b) Levelling Staff- 01 No

c) Tripod stand

d) Pegs 02 No

e) Metallic tape

THEORY: A Theodolite can be used for the determination of the heights and distances of

objects, which are inaccessible. For example, the top of the Hill or an object bounded by

water. In such situations observations have to be made from two established stations. The

two instrument stations and the object may or may not be in the same vertical plane. In

this case the two instrument stations are so chosen that they are in the same vertical plane

as that of the object. This method is called as single plane method. With an adequate

number of angular and linear measurements, the required quantities can be computed from

the trigonometry of the figure.

With reference to the figure we have,

h1=D tan α1, h2= (b+D) tan α2

From the geometry of the figure, on simplification,

D= [btan α2 ±S] / [tan α1 - tan α2]

In the above expression ‘+’ sign is used when the instrument axis at the further station is

higher than that at the station near to the object and ‘-‘ sign is used for vice versa.

RL of top of the object = RL of BM + S1+D tan α1OR

RL of top of the object=RL of BM+S2+(b+D) tan α2

PROCEDURE:

1. Set the Theodolite at a convenient position from the object such that the vertical

angles shall be between 30o to 60o.

2. Level the instrument and eliminate the parallax.



3. Transfer the instrument center to the ground with a plumb bob as

station ‘A’.

4. Obtain the vertical angle above the horizontal axis at stn. ‘A’ to the top of the

object by accurately sighting the top using the vertical clamp and tangent screw.

5. Repeat step No.4 by changing the face and obtain the average vertical angle at ‘A’

6. Keeping the line of collimation horizontal take staff reading on the B.M.

7. Transit the Theodolite so as to locate station ‘B’ in the same vertical plane.

8. Measure a suitable distance ‘b’ from station ‘A’ to locate station ‘B’.

9. Shift the instrument to station ‘B’ and carry out centering and leveling.

10. Obtain the vertical angle above the horizontal axis at stn. ‘B’ to the top of the


11. Repeat step No.10 by changing the face and obtain the average vertical angle at

‘B’.


13. Calculate the height and RL of the object using the trigonometric formulations.



Distance and Elevation of an inaccessible object by Single Plane Method.

FIGURE

Fig.11.1: Single Plane Method

OBSERVATIONS


Insrument

Stn

Point

Sighted

Face : Left Swing :

Right


o ‘ “ ‘ “ o ‘ “ o ‘ “

A TOP

B TOP

h1=Dtanα1



Insrument

Stn

Point

Sighted

Face : Right Swing :

Left


o ‘ “ ‘ “ o ‘ “ o ‘ “

A TOP

B TOP

The average vertical angles are

α1 = α2 =

2.Staff reading on Bench Mark

From station ‘A’=S1=

Form station ‘B’=S2=

3. Horizontal distance between stn. ‘A’ and stn.’B’= b = -------

CALCULATIONS AND RESULTS:

Distance from station ‘A’ to the object, D= [ btan α2 ±S] / [tan α1 - tan α2] = -----M

RL of top of the object=RL of BM+S1+ D tan α1 = ------M

CHECK:

RL of top of the object= RL of BM+S2+ (b+D) tan α2 =-----------M



Distance and Elevation of an Inaccessible Object by Double Plane Method.

AIM: To determine the distance reduced level of an elevated object whose base is

inaccessible from the instrument station.

INSTURMENTS AND ACCESSORIES:

(i) Transit Theodolite with accessories (iv) leveling /staff-01 No

(ii) Tripod stand (v) Pegs-02

(iii) Metallic Tape

THEORY: A Theodolite can be used for the determination of the heights and distances

of objects, which are inaccessible. For example the top of a hill or an object bounded by

water. In such situations observations have to be made from two established stations. The

two instrument stations and the object may or may not be in the same vertical plane. In

this case the two instrument stations are so chosen that they are in the two different

vertical planes as that of the object. This method is called a double plane method. With an

adequate number of angular and linear measurement, the required quantities can be

computed from the trigonometry of the figure.

With reference to the figure we have,

h1=D1 tan α1 h2=D2 tan α2

From the geometry of the figure, on simplification,

D1=[bSinƟ2] / [Sin(1 + 2] And D2 =[bSinƟ1] / [Sin(1 + 2]

RL of top of the object=RL of BM +S1+h1

RL of top of the object=RL of BM+S2+h2

PROCEDURE:

1. Set the Theodolite at a convenient position from the object such that the vertical

angle shall be between 30o to 60o

2. Level the instrument and eliminate the parallax.

3. Transfer the instrument center to the ground with a plumb bob as station ‘P’.

4. Obtain the vertical angle above the horizontal axis at station. ‘P’ to the top of the


5. Repeat step No.4 by changing the face and obtain the average vertical angle at

‘P’.




7. Locate station ‘R’ at a suitable distance from ‘P’ such that the angles of the

horizontal triangle formed by station ‘P’, station ‘R’ and the object shall be

between 30o to 60o.

8. Measure the distance ‘b’ from station ‘P’ to station ‘R’.

9. Shift the instrument to station ‘R’ and carry out centering and leveling.

10. Obtain the vertical angle above the horizontal axis at station ‘R’ to the top of the


11. Repeat step No. 10 by changing the face and obtain the average vertical angle at

‘R’.


13. Calculate the height and RL of the object using the trigonometric formulations.

Distance and Elevation of an inaccessible object by Double plane Method

FIGURE:

Fig.11.2: Double Plane Method





Insrument

Stn

Point

Sighted

Ver ‘C’ Ver ‘D’ Vernier Mean Vertical Angle-

α1

o ‘ “ ‘ “ o ‘ “ o ‘ “

PLeft TOP

PRight TOP

Insrument

Stn

Point

Sighted

Ver ‘C’ Ver ‘D’ Vernier Mean Vertical Angle-

α2

o ‘ “ ‘ “ o ‘ “ o ‘ “

RLeft TOP

RRight TOP

The average vertical angles are: α1= α2=



2.Measurement of Horizontal Angles

Insrument

Stn Point Sighted

Ver ‘A’ Ver ‘B’ Vernier Mean Horizontal

Angle

Average

Horizontal

Angle-θ1

o ‘ “ ‘ “ o ‘ “ o ‘ “ o ‘ “

PLeft Elevated Object

R

PRight Elevated Object

R

Insrument

Stn Point Sighted

Ver ‘A’ Ver ‘B’ Vernier Mean Horizontal

Angle

Average

Horizontal

Angle-θ2

o ‘ “ ‘ “ o ‘ “ o ‘ “ o ‘ “

RLeft Elevated Object

P

RRight Elevated Object

P


65 Dept. of Civil Engineering Basic Surveying Practice Manual-17CVL38

The average horizontal angles are: Ɵ1= Ɵ2

3. Staff reading on Bench Mark: From station ‘P’ = S1= and from station

‘R’= S1=

4. Horizontal distance between stn. ‘P’ and stn. ‘R’=d=

CALCULATIONS AND RESULTS:

1. Distance from station ‘P’ to the object= D1 = [bSinƟ2] / [Sin (Ɵ1 + Ɵ2]

2. Distance from station ‘R’ to the object= D2 = [bSinƟ1] / [Sin (Ɵ1 + Ɵ2]

3. RL of top of the object=RL of BM+S1+h 1=-----------m

Check

RL of top of the object=RL of BM+S2+h2=--------------m



EXPERIMENT 12- To determine distance and elevation using tacheometric surveying

with horizontal and inclines line of sight.

AIM: - to determine distance and elevation using tacheometric surveying with horizontal

and inclines line of sight.


a) Tacheometer (Transit Theodolite / Dumpy level)

b) Tripod stand

c) Levelling Staff-01No

d) Metallic Tape

e) Pegs-02 Nos

f) ranging rods-03 No’s

THEORY: Tacheometry is a branch of surveying in which distances and elevations are

determined from instrumental observations only. The basic principle of stadia method of

tacheometry is that if the length of the base and the apex angle of an isosceles or right

angled triangle are known, the perpendicular distance from the apex can be calculated.

The distance formula for horizontal line of sight is

D = Ks+ C

The tacheometer is so constructed that normally K=100 and by fixing a anallactic lens the

additive Constant is made zero.

PROCEDURE:

1. Set the instrument at Q and level it. With the help of upper clamp and upper tangent

provided at the vertical circle set vernier C to 0º00´00´´. Which keeps the telescope

horizontal.

2. Direct the telescope towards the point P where distance and elevation of the point is to

be determined. Bisect point P accurately by upper clamp and tangent screws.

3. After exact bisection measure central stadia reading, staff intercept and Staff reading

on BM.




Staff Intercept = S = ……….M

Staff Reading on Benchmark = ……………M

Central Cross Hair reading = ………………M

Fig.12.1: Tacheometric Surveying – Horizontal Line of Sight

FORMULA

1)Distance, D=KS+C

2)Elevation = RL of Bench mark +Staff Reading on BM-Central Stadia Reading.

RESULT:

1) Distance=…………….…..M

2) Elevation = ………………M



2) AIM :To determine distance and Elevation using Tachometric surveying with

Inclined line of sight


Tachometer, Leveling Staff, Chain or tape.

DIAGRAM

Fig.12.2: Tacheometric Surveying – Inclined Line of Sight

PROCEDURE

1. Set up the theodolite over the station O and level it accurately with reference to the

altitude bubble from where the distance and elevation are to be measured.

2. Unclamp the vertical circle clamp and direct the telescope towards the Staff placed at

elevated object at any inclined angle.

3. Read both the verniers C and D. The mean of the two readings gives the value of

required angle.

4. After measuring the vertical angle measure central stadia reading, staff intercept and

Staff reading on BM in order to calculate the distance and measurement.




Staff Intercept = S = ……….M

Staff Reading on Benchmark = ……………M

Central Cross Hair reading = ………………M

Angle of elevation = o ’ ”

FORMULA

1)Distance, D=KSCos2+C Cos

2)Elevation = RL of Bench mark +Staff Reading on BM+V-h.

RESULT:

1) Distance=…………….…..M

2) Elevation = ………………M



EXPERIMENT 13-Closed traverse surveying using theodolite and applying corrections

for error of closure by transit rule.

AIM: To measure the bearings of the sides of the closed traverse and adjustment of the

closing error by Transit rule.


a. Theodolite with stand

b. Chain/tape

c. Ranging rods

d. Arrows.

THEORY:

A ‘traverse’ is a frame formed by a series of connected straight lines, none of

which is connected at each of its ends to lines more than one. The points defining the ends

of the traverse line are called traverse stations or traverse points. When the lines form a

circuit which ends at the starting point is known as a closed traverse. If the circuit ends

elsewhere, it is said to be an open traverse. Closed traverse is suitable for locating

boundaries of lakes, forests etc. Open traverse is suitable for surveying along long narrow

strip of land required for a road or canal or pipeline or the coast line.

Closing error or error of closure is the actual distance by which the traverse fails

to close. Transit method may be employed to balance the traverse when the angular

measurements are more precise than the linear measurements. In this method the total

error in latitude and departure is distributed in proportion to the latitude and departure of

the traverse lines.



Fig.13.1: Closing Error – Transit Method

FORMULAE

Transit method:

CL= ∑𝑳𝑿𝑳

𝑳𝑻

CD= ∑𝑫𝑿𝑫

𝑫𝑻

Where CL= Correction to latitude of any side

CD= Correction to departure of any side

𝑙= Length of that side

∑ 𝐿= Total error in latitude

∑ 𝐷= Total error in departure

L= Latitude of that side

LT= Arithmetic sum of latitudes (Ignoring the signs)

D= Departure of that side

DT= Arithmetic sum of departures (Ignoring the signs).

PROCEDURE:

1. Let A, B, C, D, E are the traverse stations.

2. Set the Theodolite at station ‘A’ keeping theodolite reading at 0, and sighting the

line AB. Measure the distance AB.

3. Now shift the instrument to the station ‘B’, Measure the horizontal angle BC.

4. Similarly the length and angles of each line of the traverse is to be measured.




Transit Method

SL.

NO.

Line Length

(𝑙)in m

Angle Latitude

L=𝑙𝐶𝑜𝑠𝜃

Departure

D=𝑙𝑆𝑖𝑛𝜃

Corrections Corrected

Lat

itude

Dep

artu

re

Lat

itude

Dep

artu

re

1

2

3

4

5

6

∑ 𝐿= ……………∑ 𝐷= ……………

RESULT:



EXPERIMENT 14 -Demonstration of minor instruments

Hand Level

Hand level is a small compact leveling instrument which can be held in hand and leveling

work carried on. It is used for

(i) Reconnaissance and preliminary survey

(ii) Locating contours, and

(iii) Taking short cross-section

Fig.14.1: Hand Level

It consists of a rectangular tube 100 mm to 150 mm long. There is a small opening at

the top of the tube and a level tube is fitted exactly above this. The level tube is

transparent both at top and below.

Below this, in half the width of tube a mirror is fixed at 450. The other half width is

clear. At one end of the tube there is eye peep hole and at other end there is objective.

When the staff is sighted through the eye peep hole in half the portion staff is seen directly

while in other half, level bubble is seen. When in perfect adjustment, if hand level is held

horizontal, the middle of bubble and cross hair coincide and the reading is the correct staff

reading in the horizontal sight. Hence, it can be used as a leveling instrument. It is usually

held in hand at eye levels and observations are made. It may be suspended from a raging

rod for greater stability.



Box Sextant

The box sextant is small pocket instrument used for measuring used for measuring

horizontal and vernier angles, measuring chain angles and locating inaccessible points. By

setting the vernier 900 it may be used as an optical square. Fig shows a box sextant.

Fig.14.2: Box Sextant

A box sextant consists of the following parts:

(1) A circular box about 8cm in diameter and 4cm high.

(2) A fixed horizon glass, silvered at lower half and plain at upper half.

(3) A movable index glass fully silvered.

(4) An index arm pivoted at the index glass and carrying a vernier at the other end.

(5) An adjustable magnifying glass, to read the angle

(6) A milled-headed screw to rotate the index glass and the index arm.

(7) An eye ole or peep hole or a telescope for long distance sighting.

(8) A pair of colored glasses for use in bright sun.

(9) A slot in the side of the box for the object to be sighted.



Clinometer

Fig.14.3: Indian Pattern Clinometer (Tangent Clinometer)

Indian pattern clinometer is used for determining difference in elevation between

points and is specially adopted to plane tabling. The clinometer is placed on the plane

table, which is leveled by estimation. The clinometer is composed of the following:

1. A base plate carrying a small bubble tube and a leveling screw. Thus, the

clinometer can be accurately leveled.

2. The eye vane carrying a peep hole. The eye vane is hinged at its lower end to the

base plate.

3. The object vane having graduations in degrees at one side and tangent of the angles

to the other side of the central opening.

The object vane is also hinged at its lower end to the base plate. A slide provided with

a small window and horizontal wire in its middle, can b moved up and down the object

vane by a rack and pinion fitted with a milled head. The line of joining the peephole and

the horizontal wire of the slide defines the line of sight. When the instrument is not in use,

the vanes fold down over the base.

Use of Indian pattern clinometer with plane table

1. Set the plane table over the station and keep the Indian pattern clinometer on it.

2. Level the clinometer with the help of leveling screw.

3. Looking through the peephole, move the slide of the object vane till it bisects the

signal at the other point to be sighted. It is preferable to use a signal of the same

height as that of the peephole above the level of the plane table station.



4. Note the reading, i.e. tangent of the angle, against the wire. Thus, the difference in

elevation between the eye and the object distance X tangent of vertical angle d tan

a.

The distance d between the plane table station and the object can be found from the

plan. The reduced level of the object canthus be calculated if the reduced level of the plane

table station is known.

Ceylon Ghat Tracer

This instrument illustrated in fig is used for setting out a grade contour, i.e. locating points

on a given gradient in the preliminary survey of a hill road, and also for measuring the

angles of slope.It consist of

1. a hollow brass sighting tube suspended from a bracket and having a very small

hole (eye hole) at one extremity to which the eye is applied, and a larger opening

with cross-wires at the other the tube pivots round the point P and is held

suspended from an upright staff,

2. A horizontal racked bar the bar is parallel and rigidly and attached to the tube at a

distance of about 2.5 cms from it

3. A weight the upper part of which forms the reading index the weight can be moved

along the rack by means of a million-head screw actuating a pinion on the rack.

The line of sight is defined by the line joining the centre of the eye hole to the intersection

of the cross-wires. The sighting tube and along with it the line of sight can be set to any

desired gradient by moving the weight along the rack to the required reading on the scale.

Fig.14.4: Cylon Ghat Tracer



Procedure: - Suppose it is required to lay out a gradient of 1 in 30 along a hill slope.

1. Hold the instrument at the given station suspending it from the pin inserted in the

upright staff.

2. Move the weight along the rack by means of the milled-head screw until the index

reads 30 on the scale.

3. Send an assistant with a sight vane (a T-shaped staff on which is marked the height of

the axis of the sighting tube above the foot of the suspending staff) to a convenient

distance, say 50 m or more along the hill slope.

4. Look through the sighting tube and direct the assistant to move up or down hill until

the cross-wires bisect the centre of the sight vane.The foot of the sight vane is then the

required point and the line from the instrument station to this line is parallel to the line

of sight is on a gradient of 1 in 30.As peg is driven at the point so obtained which

serves as the instrument station for locating the next point.

5. Proceed to the point so established and repeat the operation to locate the next point.

To measure a slope,

1.Hold the instrument at one end of the slope and a sight vane at the other.

2.Move the weight along the rack by turning the middle head screw until the centre of the

sight vane is bisected by the cross-wires.

3.Note the reading at the index edge of the weight, which gives the amount of slope

observed.

Planimeter

Fig.14.5: Planimeter



A Planimeter is an instrument, which measures the area of plan of any shape very

accurately. There are two types of planimeters: (1) Amsler polar Planimeter, and (2) Roller

Planimeter.

The polar Planimeter is most commonly used and is therefore discussed here. It

consists of two arms hinged at a point known as the pivot point. One of the two arms

carries an anchor at its end, and is known as the anchor arm. The length of anchor arm is

generally fixed, but in some of the planimeters, a variable length of anchor arm is also

provided. The other aim carries the tracing point at its end, and is known as the tracing

arm. 1 ho length of the tracing arm can be varied by the means of a fixed screw and a

corresponding slow motion screw. The tracing point is moved along the boundary of the

plan the area of which is to be determined. The normal displacement of the tracing arm is

measured by the means of a wheelhouse axis is kept parallel to the tracing arm. The wheel

may either be placed between the hinge and the tracing point or is placed beyond the pivot

point away from the tracing point. The wheel carries a concentric drum, which is divided

into 100 divisions small vernier attached near the drum, reads one-tenth of the drum

division. The complete revolutions of the wheel are read on the disc actuated by a suitable

gearing to the wheel. Thus, each is reading is of four digits-the units being read on the

disc, the tenths and hundreds on the drum, and the thousands on the venire. In addition to

this, a fixed index near the disc can be utilized to know the number of the times the zero of

the disc has crossed the index.

It is clear that the planimeter rests on three points-the wheel, the anchor point and

the tracing point. Out of these three, the anchor point remains fixed in position while the

wheel partly rolls and partly slides as the tracing point is moved along the boundary. Since

the plane of the wheel is perpendicular to the plane of the centerline of the tracing arm, the

wheel measures only the 'normal displacement- when it actually rolls.

To find the area of the plan, the anchor point is either placed outside the area (if the

area is small) or it is placed inside the area (if the area is large). A point is then marked on

the boundary of area and the tracing point is kept exactly over it. The initial reading of the

wheel is then taken. The tracing point is now moved clockwise along the boundary till it

comes to the starting point. The final reading of the drum is taken. The area of the Figure

is then calculated from the following formula:

AREA () = m (FR – IR (+or-) 10 N + C)



Where FR = Final reading.

IR = Initial reading

N = The number of times the zero mark of the dial passes the fixed index Mark. Use +

sign if the zero mark of the dial passes the index mark in a Clockwise direction and - sign

when it passes in anticlockwise direction.

M = A multiplying constant, also sometimes known as the planimeter constant. It is equal

to the area per revolution of the roller.

C = constant of the instrument which when multiplied by M, gives the area of zero circle.

The constant C is to be added only when the anchor point is inside the area.

It is to be noted that, the tracing point is to be moved in the clockwise direction only.

Proper sign must be given to N. The proof of the above formula is given below.

Pentagraph

Fig.14.5: Pentagraph

A Pentagraph is an instrument used for reproducing, enlarging or reducing the

maps. It is based on the principle of similar triangles. It consists of two long bars AB and

AD hinged together at A and supported on casters or rollers at B and D. Two short arms

EF and GF are hinged together at F and are connected to AD and AB at E and G

respectively. Thus ABGF is a parallelogram of equal sides for all positions of the

instrument. The long bar AD carries a tubular frame which can be slided along it. The

sliding frame carries an index and a heavy weight Q which forms the vertical axis of the



instrument; the whole instrument moves about the point Q. The bar EF carries a pencil

point P attached to a carrier which can also be set to a desired reading on the bar EF. The

longer arm AB carries tracing point at the end B. For any setting of the instrument, the

point B, P and Q are in straight line. The original map is kept at B and is traced.

Correspondingly, the pencil point P also moves, but the point Q remains fixed in position.

Thus, if B, is moved straight by an amount BB', the point P moves to P', the ratio between

BB' and PP' being equal to the ratio of reduction. For any position of the tracing point, the

points B', P' and Q are always in a straight line.

If it is desired to enlarge the nap, the pencil point is kept at B, the tracing point at P

and the map under the point P. The moving frames at Q and P are set to the same reading

equal to the ratio of enlargement. The pencil can be raised off the paper, by means of cord

passing from the pencil round the instrument to the tracing point, if so required.



Additional Exercise

1. Preparation of Google mapping for sampling points

2. Conducting differential levelling using total station.



Viva-Voce

Linear Measurements

1. What is the fundamental difference between surveying and leveling?

2. What is the fundamental difference between plane surveying and geodetic surveying?

3. What do you mean by the terms ‘topographical map’ and ‘cadastral map’?

4. What is the main principle of surveying?

5. How is a chain folded and unfolded?

6. In a chaining operation, who is the leader and who the follower?

7. While chaining a line, you have to measure through a steep sloping ground. What

method should you apply?

8. Two stations are not intervisible due to intervening high ground. How will you range

the line?

9. What do you mean by normal tension?

10. What do you mean by RF?

11. What is difference between plain scale and diagonal scale?

12. What is hypotenusal allowance?

13. How many ranging rods are required to range a line?

14. What is the length of one link in a 20 m chain?

Chain Surveying

1. What is the principle of chain surveying?

2. What do you mean by triangulation?

3. Why is the triangle preferred to the quadrilateral?

4. What is the disadvantage of using ill-conditioned triangles?

5. What is reconnaissance survey?

6. What is an index sketch?

7. What is ‘base line of survey’?

8. How is the north line of the chain survey map fixed?

9. Suppose you are asked to conduct a chain survey in a crowded town. What would you

say?

10. What should be the maximum length of offset?

11. How is a station marked on the ground?



12. What is the need of a reference sketch?

13. How will you set up a perpendicular with the help of only a chain and a tape?

14. Who are the ‘leader’ and ‘follower’ when a line is being chained?

15. Why does the field book open lengthwise?

16. Why is the scale always drawn in the map?

17. What is it necessary to provide tallies in a chain?

18. What do you mean by the term ‘ideal triangle’?

Compass Traversing

1. What is the principle of compass surveying?

2. What is the difference between triangulation and traversing?

3. What does the term ‘chain angle’ mean?

4. What is a 12cm compass?

5. What is the fundamental difference between the prismatic compass and the surveyor’s

compass?

6. How would you detect the presence of local attraction in an area?

7. The FB of a line is 96o30’ and 276o0’. How will you adjust the bearings?

8. What is local attraction?

9. What is declination?

10. What are isogonic and agonic lines?

11. What do you mean by azimuth?

12. What FB of a line is 145030’ what is its BB?

13. The FB of a line is S 45030’ w? What is its BB?

14. What are the precautions to be taken while shifting a prismatic compass from one

station to another?

15. A compass was properly balanced at the equator. What will be the effect on the needle

if it is taken to the northern hemisphere?

16. What is the angular check of a closed traverse?

17. How would you check the accuracy of open traverse?

Levelling

1. What is a datum surface?

2. What does the term GTS mean?

3. What are bench-marks?



4. What is the datum adopted for GTS bench-marks?

5. What are the types of BM that you know of?

6. For any engineering work, how will you get the RL of the starting point?

7. What is the difference between a level surface and a horizontal surface?

8. What is the difference between the line of collimation and axis of the telescope?

9. What is the relation between the line of collimation and the axis of a telescope?

10. In a particular set up of the level, suppose four readings are taken. How should they be

entered in the level book?

11. What is a change point?

12. The staff readings on A and B are 1.735 and 0.965 respectively. Which point is

higher?

13. What is the procedure of leveling by foot screws?

14. How is the level centered?

15. Suppose a level is given to you whose line of collimation is not in adjustment, what is

the procedure that you would follow in order to work with this instrument?

16. How will you continue leveling across a river?

17. How will you continue leveling across a lake or pond?

18. What are the arithmetical cheeks for the HI method and the rise and fall method?

19. What is fly leveling?

20. What is check leveling?

21. What is temporary bench mark?

22. Why is datum assumed for plotting a leveling operation?

23. What is difference between temporary and permanent adjustment?

24. What would you mean by positive RL and negative RL?

Theodolite Traversing

1. What is a transit theodolite?

2. What is a 12 cm theodolite?

3. What are the functions of a theodolite?

4. Describe the location and function of the plate bubble and the altitude bubble?

5. What is the function of the shifting head?

6. State the procedure involved in bringing the bubble to the center?

7. What are the functions of the clamp screw, tangent screw and clip screw?



8. What do the terms ‘face left’ and ‘face right’ mean?

9. What do the terms ‘telescope normal ‘and ‘telescope inverted’ mean?

10. What is an azimuth?

11. What is a trunnion axis?

12. What is transiting?

13. What does ‘swinging the telescope’ mean?

14. What is the least count of a theodolite?

15. How can a theodolite be used as level?

16. What is a deflection angle?

17. Why are face left and face right observations taken?

18. Why are two Vernier readings taken?

19. What do you know about repeating theodolites and direction theodolites?

20. Name some modern theodolites.

21. What do the terms ‘consecutive coordinates’ and ‘independent coordinates’ mean?

22. What are latitude and departure?

23. What are the sign conventions of latitudes and departures?

24. What is Gale’s table? What is the characteristic of this table?

Tacheometric Survey

1. What is tacheometry?

2. What is the difference between a theodolite and tacheometer?

3. Why is an anallatic lens provided in a tacheometer?

4. What is the difference between a fixed hair tacheometer and a subtense theodolite?

5. What are the multiplying constant and additive constant of a tacheometer?

6. What is subtense bar?

7. What is tangential tacheometry?

8. What is the principle of tacheometry?

9. What does ‘reduction of readings’ mean?

10. What is the purpose of a direct reading tacheometer?

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