Surveying I Two Marks Questions With Answers 2014

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UNIT I - 16 MARKS QUESTIONS WITH HINTS

1. What is a survey station? State the points to be kept in view in arranging the frame work of a survey?

(Nov/Dec 2011)

Ans: Line connecting two survey points. Area to be divided equally along the longest line.

2. What is chain surveying? Explain the required accessories for chaining with neat sketches. (May/June

2012)

ANS: Chain surveying is defined as the type of surveying in which, only linear measurements are taken with the help of chain (or) tape, without any angle measuring instruments. Chain triangulation for a small area is carried out by dividing the area into number of triangles, whose sides should be easily measurable by using the chains.

3. Describe with neat sketches any two methods of chaining on sloping ground stating the advantages and disadvantages of each. (Nov/ Dec 2012) (May/June 2009) (May/June 2007)

Hint: By Reciprocal Ranging

4. Describe the various types of offsets and the method of taking offsets. .(Nov/ Dec 2012) (May/June

2009)(May/June 2007) Ans:

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

5. In a neat sketch of colony area (selected as an example) show the various features and explain the method of recording the details by conducting a chain survey and entering the details in the field book.(Nov/ Dec

2012) (May/June 2009)(May/June 2007) Hint:

Draw the field Book

6. Explain the method of direct ranging and reciprocal ranging in detail. (Nov/ Dec 2006) (Nov/ Dec 2009) (Nov/ Dec 2010) (May/June 2007) (Nov/Dec 2007)

Ans:

ü Direct ranging is defined as the process of ranging in which the intermediate stations are marked along the chain line by direct observation from either end stations. Line-Ranger is a small reflecting instrument used for locating the intermediate stations on a chain line.

ü Indirect ranging is defined as the process of ranging in which the intermediate stations are located.

7. Explain the traversing and plotting procedures of chain survey. (16) (May/June 2013)

Ans: A traverse is a series of connected straight lines, each joining the two survey stations on the ground surface. The traverse may either be open or a closed traverse. A closed traverse forms a closed polygon and

it is preferred for larger areas. An open traverse does not form a closed polygon and it is used for the survey work of a road line, railway line and long and narrow surveys.

8. Enlist the obstructions in a chain survey and explain the methods to overcome them. (Nov/Dec 2011)(16) Ans:

Various obstructions (or obstacles) in chain surveying can broadly be classified as

1. Obstacles which obstruct ranging but not chaning (Chaining free-vision obstructed).

2. Obstacles which obstruct chaining but not ranging (Vision free – chaining obstructed).

3. Obstacles which obstruct both chaining and ranging (Both chaining and vision obstructed).

9. Plot the following cross staff survey and calculate the area. ( 8) (Apr/ May 2005)

clip_image004

Ans:

Area of the triangle = ½ (bXh)

Area of the trapezium = ½ ((a+b)X h)

10. P and Q are two points 517 m apart on the same bank of a river. The bearings of a tree on the other bank observed from P and Q are N 33°40’ E and N 43°20’ W respectively. Find the width of river if the bearing of PQ is N 78 °E. (9) (Apr/May 2010)

Hint:

Draw the diagram and use Tan formula.

1. In chaining across a pond, stations M and N Y were selected on opposite sides of pond. A line MO 200 meter long was set out to the left of MN and the line MP was set out on the right side of MN such that O, N and P are lying in a straight line. The length of MP was found to be 275 m. ON and NP were measured as

125 m and 150 m respectively. Determine the distance between M and N.(10) (Nov/ Dec 2012) Hint:

Draw the diagram and use Tan formula.

12. A survey line BAC crosses a river, A and C being on the near and distant banks respectively, standing at D, a point 50 m measured perpendicularly from A, the bearings of C and B are 320 and 230 respectively, AB being 25 m. Find the width of the river. (10) (May/June 2006)

Hint:

Draw the diagram and use Tan formula.

13.A chain line ABC crosses a river. The points B and C are situated on the near and opposite sides of the river respectively. The bearing of a line BD, perpendicularly to AC at B and 50 m long is 4520’. The measured bearing of DC is 26450’. The measured bearing of DC is 264°50’. Find the distance BC.

(10) (Nov/Dec 2006) Hint:

Draw the diagram and use Tan formula.

14. A 30 m in steel tape was standardized at a temperature of 20°C and under a pull 5 kg. The tape was used in catenary at a temperature of 25°C and under a pull of P kg. The cross sectional area of the tape is 0.02

cm2, its weight per unit length is 22 g/m, Young’s modulus = 2 ´ 10 kg/cm2’  =11 ´ 10– 6 per °C. Find

the correct horizontal distance, if P is equal to (i) 5 kg (ii) 11 kg. (Nov/ Dec 2012) Hint:

Total correction = Correction of Sag + Correction due to Temperature + Correction due to Pull

15. Calculate the sag correction for a 30 m steel tape under a pull of 100 N in three equal spans of 10 m each. Weight of one cubic cm of steel = 0.078 N. Area of cross-section of tape 0.08 sq.cm. (12) (May/June

2006)

Correction of Sag= n/24 (P/W)2


UNIT II

1. What are the essential differences between chain survey and compass survey? In what circumstances compass survey is prepared over others? (Nov/Dec 2010)

Ans: Chain surveying is the best method of calculating the area for smaller areas. For larger areas and for larger fields, chain survey is not suitable because of the less accuracy, and hence the accuracy of the survey is obtained by measuring the direction (angles) and distance of the surveying stations. In such cases the traversing method is suitable than the chain triangulation.

2. What are the types of “traversing”? Explain. (4) (Nov/ Dec 2009) Ans:

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

3. Discuss the working principle of prismatic compass in detail.(Nov/ Dec 2009)(Nov/Dec 2010) (Or) With a neat sketch, explain the various parts of a prismatic compass. Explain how the graduations are

marked with and why? (8) (Apr/May 2005) [Nov/ Dec 2006](May/June 2007)

Ans:

a) Compass Box

b) Magnetic Needle c) Graduated Ring

The circular ring is graduated in degrees and half-degrees, from 0to 360 the graduations are

marked in the clockwise direction, having Zero at South, 90 at West, 180 at North and 270at East. The graduations on the ring are inverted because; they are to be read by prism. When the needle is balanced on the pivot, it orients itself in the magnetic meridian. The North-South ends of the aluminium ring lie in the

N-S direction.

clip_image007

d) Eye Vane e) Prism

f) Object Vane

Graduated Ring

4. Explain about the adjustments of a prismatic compass. (4) (Nov/ Dec 2008. Hints:

1. Adjustment of Tripod

2. Adjustment of Compass etc

5. (a) Explain about surveyor’s compass. (4) (Nov/ Dec 2007) ((May/June 2006)(May/June 2013)

(b) Explain the method of surveying by using surveyor’s compass with a neat diagram. (6)(Nov/Dec

2007) Hints:

Surveyor’s compass is used in olden days and the prismatic compass is nowadays used. It is in the shape of a

circular box of diameter, of about 127 mm

6. Describe the different reference directions employed in surveying.(16) (Nov/Dec 2011) Hints:

1. Magnetic North

2. True North etc.

7. Write a note on the Whole circle bearing system and the Quadrantal bearing system and adjustments of a prismatic compass. (4 + 4) (May/June 2009)

Hints:

Whole Circle Bearing (W.C.B.)

In this system, the bearing of a survey line is measured from either true north (or) magnetic north in the clockwise direction. In this WCB system, the bearing varies from 0to 360 Prismatic compass is graduated on the whole circle bearing system. The following fig 2.1 (a) shows the whole circle bearing for various survey lines.

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Fig. 2.1.(a) WCB System Fig. 2.1.(b) RB System

Reduced Bearing (Quadrantal Bearing)

In this system, the bearing of a survey line are measured from North (or) South, whichever is nearer. In this system, both north and south directions are used as the reference meridians, and bearings are taken either clockwise (or) anti clockwise, based on the position of the line. Surveyor’s Compass is graduated in reduced bearing system.

8. Write a note on:

(1) The Whole circle bearing system and the Quadrantal bearing system.(4) (Nov/ Dec 2008)

Whole Circle Bearing (W.C.B.)

In this system, the bearing of a survey line is measured from either true north (or) magnetic north in the clockwise direction. In this WCB system, the bearing varies from 0to 360 Prismatic compass is graduated on the whole circle bearing system. The following fig 2.1 (a) shows the whole circle bearing for various survey lines.

clip_image009[1]

clip_image011[1]

Fig. 2.2.(a) WCB System Fig. 2.2.(b) RB System

Reduced Bearing (Quadrantal Bearing)

In this system, the bearing of a survey line are measured from North (or) South, whichever is nearer. In this system, both north and south directions are used as the reference meridians, and bearings are taken either clockwise (or) anti clockwise, based on the position of the line. Surveyor’s Compass is graduated in reduced bearing system.

9. What are the sources of errors in compass survey? (2) (Nov/ Dec 2005) Hints:

The errors in compass traversing may be classified as follows.

1. Instrumental Errors

2. Observational Errors

10. How does plane table survey compare with chain surveying in point of accuracy and expediency? (4)

(Nov/Dec 2007)

Ans:

1. Plotting is carried out in the field itself and hence chances of omitting any measurement are avoided.

2. Plotted details are checked easily.

3. No office work for plotting.

4. Less number of control points are required.

11. Define: “Triangle of error”. (2) (May/June 2007)(Nov/ Dec 2007)

Ans: The triangle formed, due to improper orientation of the plane table is called triangle of error. The table is then re-oriented and efforts are made to reduce the size of triangle of error.

12. List the various types of errors in plane tabling. And also state the precautionary measures to overcome them. (10) (Nov/ Dec 2010) (Apr/May 2010)

Hints: 1. Instrumental Errors.

2. Plotting Errors.

3. Manipulation and Sighting errors.

13. The following bearings were observed with a compass. Where do you suspect the local attraction? Find the correct bearings. (12) (Nov/ Dec 2007) ((May/June 2006) (May/June 2013)

AB

74°0’

BA

254°0’

BC

91°0’

CB

271°0’

CD

DE

166°0’

177°0’

DC

ED

343°0’

0°0’

EA

189°0’

AE

90’

Hints:

I. Included Angle Method:

1. Calculate the difference between FB and BB

2. Calculate IA for all stations.

3. Clear the error in IAs.

4. Correct the bearings.

II. Back Bearing Method:

1. Start from the stations not affected by L.A.

2. Correct the bearings for other stations.

14. The bearings of the sides of a traverse ABODE are as follows:

Side AB BC

Fore Bearing

107° 15’

22° 0’

Back Bearing

287° 15’

202° 0’

CD DE

281° 30’

189° 15’

101°30’

9° 15’

EA

124° 45’

304° 45’

Compute the interior angles of the traverse. (10) (Apr/ May 2005) Hint:

I. Included Angle Method:

1. Included Angle = BB of previous line- FB of next line

2. Check : Sum of I.A. = (2n-4) X 90

15. The following fore and back bearings were observed in traversing with a compass in place where local attraction was suspected. Find the corrected fore and back bearings and the true bearing of each of the lines given that the magnetic declination was 10° W. (12) (May/June 2007)

Line F.B. B.B. Line F.B. B.B. AB 38° 30’ 219° 15’ CD 25°45’ 207°15’

BC 115°20’ 296°35’ DE 224°50’ 44°05’

Hint:

I. Included Angle Method:

1. Calculate the difference between FB and BB

2. Calculate IA for all stations.

3. Clear the error in IAs.

4. Correct the bearings.

II. Back Bearing Method:

1. Start from the stations not affected by L.A.

2. Correct the bearings for other stations.

16. The following are the bearings of the lines of a closed traverse ABCD (6)

Line Bearing

AB N 4510’ E BC S 60 40’ E CD S 9 50’ W DA N 80 40’ W

Calculate the interior angle of the traverse.

Hint:

I. Included Angle Method:

1. Included Angle = BB of previous line- FB of next line

2. Check : Sum of I.A. = (2n-4) X 90

17. Explain the method of conducting a two point problem in the field. (May/June 2006) (May/June

2009) (Nov/ Dec 2009)(Nov/Dec 2010)

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.

18. Explain the different operations involved in working with plane table. (16) (Nov/ Dec 2005) Hints:

Please refer 2 Marks

19. Describe the different methods of plane tabling. (Nov/ Dec 2005) (May/June 2007) (May/June 2012) Hints:

Please refer 2 Marks

20. Explain the radiation and Intersection methods of plane tabling. (8) (Nov/Dec 2008) (Nov/ Dec 2010) Hints:

Please refer 2 Marks

21. Write short notes on the following on plane table surveying: (i) Radiation

(ii) Intersection

(iii) Traversing

(iv) Resection (April/May 2008) (April/May 2011)

Hints:

Please refer 2 Marks

22. What is a “Planimeter”? Explain how the volume of a reservoir could be determined through plane table and contour surveying. (8) (Nov/ Dec 2007)

Hints:

Planimeter is an instrument used to measure the area of figures in drawing drawn by plan tabling.

23. Name the various characteristical methods of Plane Tabling. Explain with sketches anyone of them.

[Nov/ Dec 2006](May/June 2007) Hints:

Please refer 2 Marks

24. What is ‘orientation’ in Plane Table survey? Explain any one method of achieving it. (2 + 4)

(Nov/ Dec 2006) Hints:

Please refer 2 Marks


UNIT III

1. Explain the principles of levelling in detail, with suitable examples. (16) (Nov/ Dec 2011) Hints:

Levelling is defined as the process of determining the relative elevations (or heights) of the points on (or)

above (or) beneath the surface of the earth. Levelling is the branch of surveying which deals about the measurements in the vertical planes.

2. Name the line of axes involved in levelling. And discuss the need for the different adjustment of the level. (8) (May/June 2012)

Ans:

1. Axis of the bubble tube

2. Vertical axis

3. Axis of the telescope

4. Line of collimation

3. The following staff readings were observed successively with level, the instrument having been moved forward after the second, fourth and eighth readings.

0.875, 1.235, 2,310, 1.385, 2.930, 3.125, 4.125, 0.120, 1.875, 2.030, 3.765.

The first reading was taken with the staff held upon a benchmark of elevation 132.135. Enter the readings in level book-form and reduce the levels. Apply the usual checks. Find also the difference in level between the first and last points. (12) (Nov/Dec 2007)

Hints:

1. Tabulate the readings

2. Select either HC or Rise and fall method and Calculate RLs.

4. Explain the temporary adjustments for a dumpy level. (8) (Nov/ Dec 2007)

Ans:

(a) Setting up the level

(b ) Levelling of instrument

(c ) Elimination of parallax

5. List out the permanent adjustments of levelling instrument(4) (Nov/ Dec 2009) Ans:

The important objective of the permanent adjustment is to establish the fixed relationship between the

fundamental lines of the levelling instrument. The fundamental lines of a level are as follows:

1. Axis of the bubble tube

2. Vertical axis

3. Axis of the telescope

4. Line of collimation

6. What is necessary to balance the sights during a fly levelling? (May/June 2009) Ans:

1. To measure the correct levels

2. To check the accuracy

7. What is meant by ‘sensitiveness of bubble’? How is it determined? (6) (Nov/ Dec 2010) Ans:

Sensitivity of a level tube is defined as the capability of a level tube to exhibit small deviation from the

horizontal.

8. Explain the method of profile levelling. (Nov/ Dec 2009)

Profile levelling is defined as the process of levelling, carried out along a given line, determine the elevations of points of known distances.

 Profile levelling (or) longitudinal levelling is the surveying process used for various engineering works such as road, railway, canal, sewer mains, water supply mains etc.,

9. What is the purpose of reciprocal levelling? Explain the procedure in detail. (8) (Nov/ Dec 2012)

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.

10. Explain

(i) Reciprocal levelling

(ii) Fly levelling

(iii) Differential levelling

(iv) Simple levelling and state where each is used.

(16) (Apr/May 2011) Hint:

Refer Two marks

11. Explain with neat sketches, how levelling is done in the following circumstances. (a) Taking level of an overhead point

(b) Levelling past a high wall. (6) (May/June 2007)

Hints:

1. By using Reciprocal ranging Method

12. Explain the sources of various errors in levelling. (Nov/ Dec 2012) Hints:

Errors in levelling can be classified as follows.

1. Manual Errors

2. Instrumental Errors

3. Errors due to natural causes

13. List some of the difficulties encountered in levelling. Explain the adjustment for making vertical axis truly vertical of the theodolite. (8) (Nov/ Dec 2007) (Nov/ Dec 2005)

Hints:

The following are some of the difficulties generally experienced in levelling operation.

1. Levelling in undulating terrain

2. Levelling across lake

3. Levelling across river

4. Levelling across an intervening high wall

5. Benchmark is above the line of collimation

6. Levelling on steep slopes

14. Discuss the effects of curvature and refraction in levelling and derive the expression for these corrections. (9) (Apr/May 2010)

In precise levelling, the effect of curvature and refraction on the staff reading is to be considered. These effects are high when the distance exceeds 200 m or so.

Hints:

The curvature correction is negative in sign and hence,

True staff Reading = Observed Staff Reading – 0.0785 D2

1

Correction for Refraction= 7 ´

D2

2R = 0.0112 D2

 

15. Calculate the RL of each point and apply the usual checks for the following dumpy level consecutive readings. The instrument having been shifted after

the fourth and eighth readings. The first reading was taken on the B.M of

822.720 m. (12) (Nov/ Dec 2009)

0.885

1.640

2.89

3.010

0.955

0.695

0.585

0.255

1.535

1.000

2.140

     

Hints:

1. Tabulate the readings

2. Select either HC or Rise and fall method and Calculate RLs.

16. The following consecutive readings were taken with a dumpy level and 4 m levelling staff on a continuously sloping ground at 30 m intervals.

0.680, 1.455, 1.855, 2.330, 2.885, 3.380, 1.055, 1.860, 2.265, 3.540, 0.835, 0.945, 1.530 and 2.250.

R.L of the starting point was 80.750 m.

(i) Rule out a page of a level book and enter the above readings. (3) (ii) Determine the RL of various staff stations. (10) (iii) Estimate average gradient of ground measured. (3) (Apr/May 2010)

Hints:

1. Tabulate the readings

2. Select either HC or Rise and fall method and Calculate RLs.

17. The following consecutive readings were taken with a dumpy level

3.864, 3,346, 2.932, 1.952, 0.854, 3.796, 2.639, 1.542, 1.934, 0.864, 0.665.

The level was shifted after the fifth and eighth reading was taken on the bench mark of RL 150.250. Calculate the reduced levels of change points and the difference in elevation between the first and last points. (12) (Apr/ May 2005)

Hints:

1. Tabulate the readings

2. Select either HC or Rise and fall method and Calculate RLs.


UNIT IV

1. Explain the LS and CS method. (8) (May/June 2013) Hints:

Longitudinal levellings are carried out along the centreline of the alignments for the proposed projects for

highways, railways, pipelines, canals, etc. The alignment is made of straight lines (or) a series of straight lines connected by curves.

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

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

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. What is meant by contour interval (C.I)? Explain how proper C.I. is to be chosen? (8)

Hints:

The vertical distance between any two consecutive contour lines is called Contour Interval.

Contour interval depends on the following factors.

1. Scale of the contour map

2. Purpose of the contour map

3. Nature of the ground

4. Availability of time and funds

3. Draw the contour lines for the following characteristics features.

Pond, Ridgeline, Valley and Depression. (4 ´ 2) (May/June 2006) Refer Text Book

4. Define contours and give characteristics of contours. (16) (Apr/May 2011) (Nov/ Dec 2009) (May/June 2012) (Nov/ Dec 2005) (Nov/ Dec 2012)

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.

5. Explain the different methods of contouring. (May/June 2012) (Nov/ Dec 2012) (May/June 2006) (Nov/ Dec 2010) (Apr/May 2010) (May/June 2006)(Nov/FDige.c42.30.1C0o)ntour lines

of a Pond

Hints:

The methods of contouring are classified as follow: (a) Direct Method

(b ) Indirect Method

6. Describe the three indirect methods of locating contours.(8) (Nov/ Dec 2009) (Nov/ Dec 2010)

Hints:

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

1. By Squares

2. By Cross-Sections

3. By Tacheometric method

7. Describe the radial method of contouring. (8) (May/June 2006) Hints:

It is also the direct method with a little variation. In this method, various points are located along the

radial lines, and the radial lines are formed from a common point at the Centre.

8. What is meant by interpolation of contours? Describe the various methods used.(10) (Nov/ Dec 2010) Hints:

Interpolation of contour is defined as the process of drawing the contours, proportionately between the

plotted ground points (or) plotted contours. Interpolation is based on the assumption that the slope of the ground between any two points is uniform. It is carried out by any one of the following methods.

1. Estimation Method

2. Arithmetical Calculation Method

3. Graphical Method

9. List the uses of contours. (6) (May/June 2012)(Apr/ May 2005) Hints:

Following are the important uses of contour maps.

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. How will you determine the inter-visibility of points from a contour map? (4) (Apr/ May 2005) Hints:

By calculating C.Intervals

11. Explain how you would determine the capacity of a reservoir using a contour map. (8) (Apr/ May

2005) (Nov/ Dec 2005) (May/June 2006) (May/June 2007) (Nov/ Dec 2008) Hints:

1. By using Sympson’s Formula

2. By using Prismoidal Formula

12. List the various methods of determining areas from offsets to a baseline. (4) (May/June 2006) Hints:

1. By using Sympson’s Formula

2. By using Prismoidal Formula

13. The following perpendicular offsets were measured from a chain line to an irregular boundary.

Calculate the area between the chain line and the irregular boundary using (12) (May/June

2012)

(1) Trapezoidal rule and

(2) Simpson’s rule

 

Chainage(m) :

0

20

40

60

80

100

Hints:

Offset (m):

2.4

1.8

3.6

2.8

3.2

2.0

(a) Trapezoidal Rule

h æ ö

Volume, V =

2 è (A1 + An) + 2(A2 + A3 + ¼¼ + An – 1) ø

ç ÷

(b) Prismoidal Rule

h æ ö

Volume, V =

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

ç ÷

14. The following perpendicular offsets (in metres) were taken at 15 m intervals from a chain line to an irregular boundary line:

3.50, 4.30, 6.75, 5.25, 7.50, 8.80, 7.90, 6.40, 4.40 and 3.25

Compute the area between the chain line, the irregular boundary and the end offsets by Trapezoidal rule and Simpsons rule. (6) (Nov/ Dec 2010)

Hints:

(a) Trapezoidal Rule

h æ ö

Volume, V =

2 è (A1 + An) + 2(A2 + A3 + ¼¼ + An – 1) ø

ç ÷

(b) Prismoidal Rule

h æ ö

Volume, V =

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

ç ÷

15. The offsets taken at 5 m intervals from a chain line to a curved boundary are:

0, 4.6, 6.5, 6.8, 5.2, 3.5, 2.2 metres. Calculate the area between the chain line, the curved boundary line

and the end offsets using Simpson’s rule. (8) (Apr/May 2011)


UNIT V

1. Describe the essential parts of a transit theodolite.(Nov/ Dec 2006) (Nov/ Dec 2009) (Nov/ Dec 2012) (May/June 2012)

Hints:

1. Top Assembly (Alidade Assembly)

2. Middle Assembly (Horizontal Circle Assembly)

3. Bottom Assembly (Levelling Head Assembly)

2. What are ‘face left’ and ‘face right’ observations? Explain (8) (May/June 2006) (Nov/ Dec 2006) Hints:

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

Left.

When the vertical circle of the theodolite is on the right of the observer, then the telescope position is called

Face Right.

3. Write short notes on adjustment of Vernier Transit Theodolite. (4) (May/June 2012) Hints:

Before taking the measurement by a theodolite, it should be adjusted to get the correct reading. These adjustments, for a theodolite are of two types.

1. Temporary Adjustment

2. Permanent Adjustment

4. Why the need of different adjustment to be carried out in theodolite? Describe them in detail. (4)

(May/June 2012) Hints:

Before taking the measurement by a theodolite, it should be adjusted to get the correct reading. These adjustments, for a theodolite are of two types.

1. Temporary Adjustment

2. Permanent Adjustment

5. Discuss the temporary adjustments of a transit theodolite.(Nov/ Dec 2009) (Nov/ Dec 2010)(May/June

2006) (Nov/ Dec 2006) (Apr/May 2008)(Nov/ Dec 2006) (Nov/ Dec 2010) Hints:

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

temporary adjustments.

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

6. Explain the steps to eliminate Parallax. (8) (Nov/ Dec 2011) Hints:

Parallax is defined as the apparent change in the position of the object, caused by the change in position

of the observer’s eye. In the theodolite telescope, the parallax is formed, when the image formed by the objective is not situated in the plane of

cross-hairs. Parallax effect can be eliminated as follows.

(a) Focussing the eye piece

(b) Focussing the objective

7. Explain the adjustment for making vertical axis truly vertical of the theodolite. (8) (Nov/ Dec 2007) Hints:

1. Make the plate bubbles central to their run when the vertical axis of the theodolite is truly vertical (plate level test)

2. Make the vertical Cross-hair lie in a plane perpendicular to the horizontal axis (Cross – hair ring test)

3. Make the line of sight perpendicular to the horizontal axis (collimation in Azimuth test)

4. Make the horizontal axis perpendicular to the vertical axis (Spire test)

5. Make the telescope bubble central when the line of sight is horizontal (Bubble tube adjustment)

6. Make the vertical circle to indicate zero when the line of sight is perpendicular to the vertical axis (Vertical arc test)

8. Describe briefly about temporary and permanent adjustments of a theodolite. (16) (Apr/May 2011) Hints:

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

temporary adjustments.

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

2.

1. Make the plate bubbles central to their run when the vertical axis of the theodolite is truly vertical

(plate level test)

2. Make the vertical Cross-hair lie in a plane perpendicular to the horizontal axis (Cross – hair ring

test)

3. Make the line of sight perpendicular to the horizontal axis (collimation in Azimuth test)

4. Make the horizontal axis perpendicular to the vertical axis (Spire test)

5. Make the telescope bubble central when the line of sight is horizontal (Bubble tube adjustment)

6. Make the vertical circle to indicate zero when the line of sight is perpendicular to the vertical axis

(Vertical arc test)

9. List out the permanent adjustments of a Theodolite and explain any two of them. (2 + 8) (Nov/ Dec

2005) (Nov/ Dec 2011) (May/June 2013)

1. Make the plate bubbles central to their run when the vertical axis of the theodolite is truly vertical

(plate level test)

2. Make the vertical Cross-hair lie in a plane perpendicular to the horizontal axis (Cross – hair ring

test)

3. Make the line of sight perpendicular to the horizontal axis (collimation in Azimuth test)

4. Make the horizontal axis perpendicular to the vertical axis (Spire test)

5. Make the telescope bubble central when the line of sight is horizontal (Bubble tube adjustment)

6. Make the vertical circle to indicate zero when the line of sight is perpendicular to the vertical axis

(Vertical arc test)

10. Write in detail about the following permanent adjustments

(1) Adjustment for vertical axis

(2) Adjustment for line of collimation

(3) Adjustment for horizontal axis (May/June 2007) Refer the answer for above question

11. Explain angle measuring procedures using theodolite. (8) (May/June 2013)

Hints:

1. Measurement of horizontal angles

2. Measurement of Vertical Angles

3. Measurement of magnetic bearing of a line

4. Measurement of direct angles

5. Measurement of deflection angles

6. Prolongation of straight line

7. Running a straight line between points etc

12. What are the possible sources of errors while using a theodolite? (8) (Nov/ Dec 2007) (Nov/ Dec 2010) Hints:

The various errors in theodolite surveying can be grouped as follows.

1. Instrumental Errors

2. Observational Errors

3. Error due to natural causes