Surveying I Two Marks Questions With Answers 2014

Anna University, Chennai

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DHANALAKSHMI SRINIVASAN INSTITUTE OF RESEARCH AND TECHNOLOGY SIRUVACHUR, PERAMBALUR – 621113

DEPARTMENT OF CIVIL ENGINEERING

UNIT I - TWO MARKS QUESTIONS AND ANSWERS

1. Define surveying and list out its various classification. (Nov/Dec 2005) Classify surveying based on instrument used. (May / June 2006)

Based on the instruments used and method of surveying, it can be classified as follows.

1. Chain Surveying 2. Compass Surveying

3. Plain Table Surveying 4. Level Surveying (or) Levelling

5. Theodolite Surveying 6. Tacheometric Surveying

7. Total Station Surveying etc.

2. What is the object of Surveying? (May / June 2012)

Following are the various purposes of the surveying methods.

1. To check out the alignment of various engineering structures.

2. To calculate the areas and volumes, involved in the various engineering projects.

3. To prepare the plans and maps, sections (or) profiles, contours, etc.

3. Write the difference between a map and a plan.

Sl. No

Fac tor

Map

Plan

1.

Sca le

Maps are the drawing with a small scale.

Plans are also the drawing with larger scale.

2.

Det ails

A map generally deals about the geographical details.

A plan deals about the details of the engineering structures.

4. What do you mean by plane surveying? (May / June 2013)

Plane surveying is defined as the division of surveying, in which all the survey works are carried based on the assumption that the surface of earth is a plane and the curvature of the earth is ignored.

5. What is meant by geodetic surveying? (Nov/Dec 2012)

The surveys, in which curvature of the earth is taken into account and higher degree of accuracy, required is called Geodetic surveying.

6. Name the different ways of Classification of surveying. (May / June 2006)

Classification of surveys based on,

(i) Purpose of surveying

(ii) Nature of the field (iii) Methods employed (iv) Instruments used

7. What are the principles of Surveying? (Nov/Dec 2009) (Nov/Dec 2010) (Or) Describe the principles of Surveying? (Apr/May 2011) (May / June 2007)

Following are the two fundamental principles of surveying. (a) Working from Whole to Part

(b ) Location of a Point

8. How do you fix a point from the control points (or a survey line)?

The position of third point can be located from the control points by any one of the following ways.

1. Two linear measurements

2. Two angular measurements.

3. One linear measurement and One angular measurement.

9. What are the instruments used for the chain surveying? (May / June 2006) (Or) List the various accessories used in chain surveying. (Nov/Dec 2006)

Following instruments are used in chain surveying

1. Chain 2. Tape 3. Ranging Rods

4. Offset Rods 5. Plumb Bob 6. Pegs

7. Cross-Staff 8. Optical Square 9. Arrows 10. Whites etc.

10. Write the equation for correction of temperature. (Nov/Dec 2009)

Temperature Correction, Ct = α (Tm ~ T0) L

Where,

α – Coefficient of thermal expansion

T m – Mean Temperature during measurements

To – Normal Temperature at standardization

L – Measured length of the line

11. What are arrows? (Nov/Dec 2009)

Chain pins (or) Arrows are the steel wire of 4 mm diameter and its length may vary from 25 cm to 50 cm. One end of the arrow is bent into a loop of a circle of 50 cm diameter and the other end is made sharped point. Arrows are used to indicate (or to mark) the end of a chain line.

12. What is Plumb Bob? (Nov/Dec 2009)

Plumb bobs are used to test the verticality of ranging rods and levelling staves. It is also used to transfer the end points of the chain onto ground while measuring the distances in a hilly terrain.

13. What is the purpose of an Optical Square? (Apr/May 2011)

Optical Squares are also like cross-staves used for setting out the right angles in change-surveying. It consists of a circular metal box about 5 cm in diameter and the 1.25 cm deep. The periphery is formed by two cylinders, one capable of sliding over the other so that the eye and object openings can be closed to protect the mirrors from the dust.

14.What do you mean by reciprocal Ranging? (Apr/May 2010) (May / June 2012) (May / June

2006) (Apr/May 2008)

Reciprocal ranging is the method of indirect ranging, and it is adopted when the two end stations are not inter-visible due to raised grounds.

15. What circumstances in which reciprocal ranging is used? (May / June 2007) (or) When do you require Indirect Ranging? (Nov/Dec 2012) (Or) Explain the use of reciprocal Ranging? (May / June

2013)

Reciprocal ranging is the method of indirect ranging, and it is adopted when the two end stations are not inter-visible due to raised grounds.

16. What do you understand by the term traversing? (Nov/Dec 2009)

Traverse is defined as the series of connected straight lines, each joining two stations on the ground. The endpoints are called traverse stations. The straight lines between the two consecutive stations are called traverse legs.

There are two types of traverse

1. Closed Traverse

2. Open Traverse

17. Who are Leader and follower when a line is being chained? (Nov/Dec 2010)

For the chaining operations, two chainmen are required. The chainman at the forward end of the chain is called a leader. The chainman at the other end of the change is called a follower.

18. In a chain how will you set out a right angle? (Nov/Dec 2011)

1. Cross-staff is the instrument used to locate the intersection point of a particular offset on a chain line

2. Optical Squares are also like cross-staves used for setting out the right angles in change-surveying.

19. Explain the use of traversing? (May / June 2013)

Traversing are used,

Ø To Fix the points on the ground.

Ø To survey when the area is large and with irregular boundaries and obstacles.

20. What are offsets? Name the types. (May / June 2007) (Nov/Dec 2007)

Offsets are defined as the lateral measurements, taken from the chain line, to locate the position of the boundaries, culverts, building, road markings, etc., An offset may be either left or right of the chain line.

There are two types of offsets, which are

(i) Perpendicular offset

(ii) Oblique offset

21. Differentiate between check line and tie line. (May / June 2009) (Nov/Dec 2006)

The line which runs across the field to check the accuracy of the survey work is called check-line (or)

proof line.

A tie-line is a one which connects the two-tie stations. Sometimes, tie lines are used to check the accuracy of the field work and used to take the offset distances.

22. Explain the terms accuracy and precision in measurement. (Nov/Dec 2007)

The degree of accuracy required in surveying is mainly depending on the purpose and scale of the map. If the scale is large, the accuracy will be higher and the accuracy is low for lower scaled maps.

23. What are different sources of errors in chain surveying? (Apr/May 2005)

(a) Displacement of the arrows

(b ) Adding (or) Omitting the full chain length (c ) Reading from the wrong end of the chain (d ) Reading numbers wrongly

(e ) Reading wrong metre marks

(f ) Recording the reading in the field book wrongly etc.

 


UNIT II - TWO MARKS QUESTIONS AND ANSWERS

1. Distinguish between angle and bearing? (May / June 2012)

An angle is defined as the deviation of one straight line with respect to the other one.

 Bearing is defined as the angle (or) inclination of a survey line with respect to the north-south direction.

2. Define true meridian. (Nov/Dec 2012) (Nov/Dec 2010)

v True meridian (or) Geographical meridian is defined as the line joining the geographical north and south poles. True meridian at various places are not parallel to each other.

3. What is magnetic meridian? (Nov/Dec 2009)

 Magnetic Meridian is defined as the longitudinal axis, indicated by the freely suspended, properly balanced magnetic needle. It does not coincide with the true meridian except in certain places during the year.

4. Define Local Attraction

The deflection of the magnetic needle from its normal position due to attraction of magnetic materials such as magnetic rocks, iron ores, electrical cables etc., is called Local Attraction.

5. What are sources of local attractions? (Nov/Dec 2006)

Magnetic materials such as magnetic rocks, iron ores, electrical cables etc., are sources of local attractions.

6. If the magnetic bearing of a line AB is 134o45’, find its true bearing if the magnetic declination is

10o15’. (Apr/May 2008)

True Bearing = Magnetic Bearing + Declination

= 134o45’ + 10o15’

= 145o

7. Define the term Dip. (Nov/Dec 2011) (Apr/May 2011)

The inclination of the magnetic needle with the horizontal plane is called Dip (or) Angle of Dip. The angle of dip at equator is 0o and it increase when approaching the poles. It becomes 90 o at poles.

8. What is Magnetic declination? (Nov/Dec 2010) (Nov/Dec 2012)

 Magnetic Declination is defined as the horizontal angle between the true north and magnetic north at a place, at the time of observation. The magnetic needle can either be deflecting, towards east (or) west of the true meridian.

9. Define Declination and Dip in compass surveying? (Nov/Dec 2006) (Nov/Dec 200

The inclination of the magnetic needle with the horizontal plane is called Dip (or) Angle of Dip. The angle of dip at equator is 0o and it increase when approaching the poles. It becomes 90 o at poles.

 Magnetic Declination is defined as the horizontal angle between the true north and magnetic north at a place, at the time of observation. The magnetic needle can either be deflecting, towards east (or) west of the true meridian.

10. Differentiate between Magnetic declination and Dip? (Nov/Dec 2009)

v The inclination of the magnetic needle with the horizontal plane is called Dip (or) Angle of Dip. The angle of dip at equator is 0o and it increase when approaching the poles. It becomes 90 o at poles.

 Magnetic Declination is defined as the horizontal angle between the true north and magnetic north at a place, at the time of observation. The magnetic needle can either be deflecting, towards east (or) west of the true meridian.

12. How the surveyor’s compass is graduated? (Nov/Dec 2009)

Surveyor’s compass is graduated from 0 o to 90o from North and South. At North and South 0 o 0 o

to 90o East and West 90o is marked.

13. Convert the following WCB into RB (a) 112o04’ (b) 339o42’ (Nov/Dec 2009)

(a) RB of 112o04’ = 180- 112o04’= S 67o56’ E

(b) RB of 339o42’ = 360- 339o42’= N 20o18’ W

14. Convert the following WCB into RB. (a) 151o 20’ (b) 332o 40’

(Apr/May 2011)

(a) RB of 151o20’ = 180 - 151o20’= S 28o40’ E

(b) RB of 332o40’ = 360 - 332o40’= N 27o20’ W

15. The bearing of a line PQ is N 50°25’ E. What is its whole circle bearing? (Nov/Dec 2006)

The bearing of given line PQ is N 50o25’ E. It lies in the first quadrant and hence, its whole circle bearing is also 50o25’

16. Convert the following RB into WCB (a) S 34°42’ E (b) N 02o18’ W

(May / June 2007)

(a) WCB of S 34o42’ E = 180- 34o42’ = 145 o18’

(b) WCB of N 02o18’ W = 360- 02o18’ = 357o42’

17. Differentiate between the fore bearing and back bearing of a line. The fore bearing of a line PQ is

N 28° W. What is its back bearing? (Nov/Dec 2005)

v The bearing of a survey line in the direction of the progress of survey is known as Fore Bearing (or) Forward Bearing (FB), and the bearing taken in the opposite direction of the progress of survey is called Reverse (or) Back Bearing (BB).

 If the fore bearing of the given line PQ is N 28o W, its back bearing is S 28o E

18. Name some of the accessories used in plane tabling. (May / June 2007)(Nov/Dec 2007)

The following instruments are used in plane tabling.

1. Plane table with tripod stand

2. Alidade (or) Sight Rule

3. Sprit Level

4. Compass

5. Plumbing Fork

6. Drawing Paper

19. Name some of the errors in plane table surveying. (May / June 2006)

Various errors in plane table surveying are classified as follows.

1. Instrumental Errors.

2. Plotting Errors.

3. Manipulation and Sighting errors.

20. What is resection in plan tabling? (May / June 2012)

 Resection is defined as the process of locating the plane table station, by back ray method from the plotted station on the sheet. This method is also called Interpolation method (or) Fixing method.

1. Back ray method

2. Two point Problem method

3. Three point Problem method

4. A box compass method.

21. What is Two-Point Problem? (May / June 2013)

 Two-Point problem is defined as the process of locating the plane-table station on the sheet, by sighting two well-defined points and its locations are already plotted on the paper.

22. Define Three-Point Problem? (Nov/Dec 2005) (May / June 2009)

Three point problems is defined as the process of locating the plane table station on the sheet by sighting three well defined points and its locations are already plotted on the paper.

23. When is plane table surveying opted? (Nov/Dec 2006)

Plane table surveying suitable,

ü When the time required to survey the area in the field is comparatively high

ü Where higher accuracy is not required.

ü For small scale maps

ü For magnetic areas, where a compass survey is not reliable.

25. What is the use of trough compass in plane table surveying? (Nov/Dec 2012)

v A trough compass in plane table surveying is used for orienting the plane table to the magnetic north.

The edge of the compass box is perfectly straight and the bottom is perfectly flat. A line along the edge of the compass is drawn, which defines the magnetic north.


UNIT III - TWO MARKS QUESTIONS AND ANSWERS

1. Differentiate between a level line and horizontal line. (May/June 2007)

 Level line is defined as the line lying on the level surface. At every point, the level surface and the level line are normal to the plumb line. The surface of still water (in a lake) represents the level surface and the level line.

vHorizontal line is defined as the line, lying on the horizontal surface. It is a straight line tangential to the level line.

2. Distinguish between line of Collimation and line of sight. (Nov/Dec 2007)

The imaginary straight line passing through the optical centre of the object and the point of intersection of the cross-hairs is called line of collimation.

The imaginary straight line passing through the optical centre of the object, traversing the eye piece and entering the eye is called line of sight.

3. State Plane of collimation and line of collimation (Nov/Dec 2011)

The horizontal plane in which the telescope of a adjusted and corrected levelling instrument about its vertical axis is called plane of collimation.

The imaginary straight line passing through the optical centre of the object and the point of intersection of the cross-hairs is called line of collimation.

4. What is Dumpy Level? (May/June 2012)

This is the simplest type of the levelling instrument and it is compact and stable. It consists of a telescope, rigidly fixed to the supports. It can neither be rotated about its longitudinal axis nor can it be removed from its supports. A long bubble tube is attached to the top of the telescope.

5. Explain the use of Dumpy level and Tilting Levels. (May/June 2013)

In tilting level, the line of sight and the vertical axis need not be exactly perpendicular to each other, and hence tilting levels are used for quick levelling.

6. What is fore sight? (Nov/Dec 2009)v Foresight is the last sight taken on a levelling staff held over an unknown elevation, before shifting the level.

7. What is back sight? (Nov/Dec 2009) (May/June 2006)

The first reading on the levelling staff, at a station of known elevation is called back sight. Back sight is used to obtain the height of the instrument.

8. Define the following terms:

Turning Point, Fore Sight, Back Sight and Bench Mark (May/June 2007)

Turning Point or Change point is defined as the instrument station, at which, the instrument is shifted from one point to another. It is the point, on which the back sight of the new station and foresight of the previous station are taken. Stable points and well-defined points are taken as the change (or) turning points.

Foresight is the last sight taken on a levelling staff held over an unknown elevation, before shifting the level.

The first reading on the levelling staff, at a station of known elevation is called back sight. Back sight is used to obtain the height of the instrument.

Reference point of known elevation is called benchmark.

9. Define Bench Mark. (Apr/May 2010) (May/June 2006)

v Reference point of known elevation is called benchmark.

10. Write the types of bench mark. (Nov/Dec 2010) (May/June 2012) (May/June 2006) (Nov/Dec

2007) (Nov/Dec 2006)

1. G.T.S. Benchmark

2. Permanent Benchmark

3. Temporary Benchmark

4. Arbitrary Benchmark

11. What are G.T.S. Bench marks? (Apr/May 2008)

v G.T.S. benchmarks are established by the GTS Department of India, with highest accuracy at an interval of about 100 km, all over the country. There elevations are referred to as M.S.L. datum.

12. What are the types of Staves? (Nov/Dec 2009) (Nov/Dec 2010)

1. Self-Reading staff

(a) Solid Staff

(b ) Folding Staff

(c ) Telescopic Staff

2. Target staff

13. What is meant by change point in levelling? (Nov/Dec 2012)

v Turning Point or Change point is defined as the instrument station, at which, the instrument is shifted from one point to another. It is the point, on which the back sight of the new station and foresight of the previous station are taken. Stable points and well-defined points are taken as the change (or) turning points.

14. What is meant by height of collimation? (Nov/Dec 2006)

v The R.L. (or) elevation of the line of collimation, when the instrument is perfectly levelled, is called the Height of the Instrument.

15. What is Reciprocal Levelling? (Nov/Dec 2006)

v It is the method of levelling and it is used when the instrument is placed equidistant from the back staff and foreword staff stations, the difference in elevation of two stations, is equal to the difference of staff readings.


UNIT IV - TWO MARKS QUESTIONS AND ANSWERS

1. Define Cross-Sectioning and its applications.

v Cross-Sectioning is defined as the process of determining the lateral outline of the ground while levelling the sections right angles to the centreline.

v The length of the cross-sections from the centreline depends on the ground features and the nature of the project.

v For the Highway Project, the length varies from 30 m to 60 m on either sides of the centreline. For the railway project, the length varies from 200 m to

300 m.

2. Define Contour. (Nov/Dec 2010) (Nov/Dec 2007) (Nov/Dec 2006)

v Contour is defined as the imaginary line, joining the points of equal elevation (RLs). It is a line of intersection of a level surface with the ground. Generally, Contour lines are marked with their elevations from the datum. The map representing the contour lines is called Contour Map.

3. Define the term Contouring. (Nov/Dec 2009)

v Contouring is defined as the process of locating the contour lines on the surface of the earth.

4. Sketch the contours of the following:

a) Hill b) Pond c) A ridge line d) A valley line (Apr/May 2005)

clip_image007

Fig. (A) A Hill or a Mound Fig. (B) A Pond

clip_image008

clip_image009

Fig. (C) A Valley Fig. (D) A Ridge Line

5. What do you mean by contour interval? (Apr/May 2011) (Nov/Dec 2012) (Nov/Dec 2005)

Contour interval is defined as the vertical distance between any two consecutive contours. It is a constant for a map.

6. Define the term Contour Gradient. (May/June 2012)

v The imaginary line, throughout the surface of the earth having a constant inclination to the horizontal is called contour gradient.

7. What is horizontal equivalent? Why it is not a constant? (Nov/Dec 2010)

v Horizontal equivalent is defined as the horizontal distance between the two consecutive contour lines. It is not a constant for a map. If the H.E. is small, it indicates the steeper slope. H.E. depends on the scope of the ground.

8. What are the methods of the indirect contouring method?

v Following three methods are generally followed in the indirect contouring method.

1. By Squares

2. By cross-sections

3. By tacheometric method

9. What are the uses of Contours? (May/June 2006)

1. To identify the topography of the place, whether the ground is flat, undulating or mountainous.

2. To finalize the most suitable and most economical sites for engineering projects such as roads, railways, reservoirs, canals, sewers etc.

3. To determine the catchment area of the drainage basin and the capacity of the reservoir.

4. To calculate the earth work for engineering projects.

5. To ascertain the intervisibility of points.

6. To identify the contour gradient for road alignment.

7. To draw the L.S and C.S to ascertain the nature of the ground.

8. To decide the intervisible and invisible points, positions of Gunman, etc., in the military field.

10. Define Mass diagram (or Mass-Haul Diagram)

Mass diagram (or Mass-Haul Diagram) is defined as the curve plotted based on distance, used to calculate the volume of cutting and filling of earth work for a project. The ordinate at any point represents the algebraic sum of cuttings and fillings, from the starting point of the earthwork to that point, considering the cuttings are taken as positive and filling are taken as negative.

11. State the limitations of Prismoidal Formula. (Apr/May 2010)

Prismoidal Formula is only applicable when the number of areas (or ordinates) are odd.

12. Write down the Prismoidal formula for finding out the volume using a contour map. (May/June

2007) (Nov/Dec 2007)

h æ ö

Volume, V =

3 è (A1 + An ) + 2(A2 + A5 + ¼) + 4(A2 + A4 + ¼ +) ø

ç ÷

Where,

h – Contour interval (in m)

A1, A2, A3 ¼ – Area covered by a contour elevation (in m2)


UNIT V - TWO MARKS QUESTIONS AND ANSWERS

1. What is transit Theodolite? (Nov/Dec 2010) (May/June 2007) (Nov/Dec 2006) (Nov/Dec 2009)

Transit theodolite is defined as the theodolite, in which its telescope can be rotated horizontally through

180o in the vertical plane.

2. List out the major parts of a Theodolite. (May/June 2012)

1. Top Assembly (Alidade Assembly)

2. Middle Assembly (Horizontal Circle Assembly)

3. Bottom Assembly (Levelling Head Assembly)

3. List the qualities of a Theodolite telescope? (May/June 2006)

Internal focusing telescopes are best suited instead of external telescopes.

The magnification factor of the internal focusing telescope should be from 15 to 30 times of the diameter.

4. State the location and function of a plate bubble of a Theodolite. (Nov/Dec 2010)

Plate bubble is placed parallel to the trunnion axis at the upper plate (or vernier plate)

5. How do you eliminate parallax in Theodolite? (May/June 2012)

v Parallax effect can be eliminated as follows. (a) Focussing the eye piece

(b) Focussing the objective

6. What are the two methods of measuring the horizontal angle using a Theodolite? When each method is advantageously used? (Nov/Dec 2005) (Nov/Dec 2006)

ü Repetition Method

ü Reiteration Method

7. What are the errors eliminated in measurements of horizontal angle by method of repetition? (Apr/May 2011) (May/June 2006) (May/June 2007)

Instrumental and Observational errors are eliminated in measurements of horizontal angle by method of repetition.

8. What you mean by temporary adjustments of a Theodolite? (May/June 2013)

v The adjustments required to be made at every instrument station before taking observations are called temporary adjustments.

v The temporary adjustments of a theodolite consist of the following operations.

1. Setting and centering the theodolite

2. Levelling of the theodolite

3. Elimination of parallax

9. What is a spire test? (Apr/May 2005)

In Sire Test, the horizontal axis (trunnion axis) is made perpendicular to the vertical axis. The objective of this adjustment is to ensure that the line of collimation revolves in a vertical plane, perpendicular to the vertical axis. This adjustment is carried out by Spire Test.

10. What is a collimation adjustment? (May/June 2012) Adjustment of the level of the Telescope

v In this adjustment, the line of collimation should remain horizontal, when the bubble of the level tube fitted on telescope is brought at the centre of its run. This adjustment is essential when a theodolite is used as a level and also when vertical angles are observed.

11. What is face right observation? (Nov/Dec 2009)

v When the vertical circle of the theodolite is on the right of the observer, then the telescope position is called Face Right.

12. Explain face left and face right observations in Theodolite traversing? (Nov/Dec 2007)

v When the vertical circle of the theodolite is on the left of the observer, the telescope position is called

Face Left.

v When the vertical circle of the theodolite is on the right of the observer, then the telescope position is called Face Right.

13. What kind of error can be eliminated by taking face left and face right observations? (Nov/Dec 2009)

v Instrumental error can be eliminated by taking face left and face right observations

ü Line of collimation not perpendicular to the trunnion axis

ü Horizontal axis not perpendicular to vertical axis

ü Vertical Index Errors