Showing posts with label CE2204 - Surveying– I 2 Mark. Show all posts
Showing posts with label CE2204 - Surveying– I 2 Mark. Show all posts

CE2204 - Surveying– I Two Mark With Answers 2nd Edition

Anna University, Chennai

 

Question Bank

Sub. Code/Name: CE2204 Surveying I Year/Sem: II/III


UNIT-I Part-A (2 Marks)

1. How surveying is defined? Name the two basic principles of surveying.

Surveying is the art of making horizontal measurements certain the. Relative positions of different objects on the face of the earth. The two basic principles of surveying are

To work from the whole to the part

To locate a, new station by at least two processes.

2. Give the fundamental difference between plane surveying and geodetic surveying.

Geodetic survey is also called as trigonometrically, eying deals with the long distances, larger areas and the curvature of the earth. Plane surveying is adopted for small distances and small areas and, earth’s curvature is ignored.

3. What is meant by reconnaissance survey?

Preliminary inspection of an area to be surveyed is reconnaissance or reconnoiters. A proper planning should be done during reconnaissance it such that the work will better and effectively executed.

4. Explain the observations made in an index sketch.

In an index sketch the following observations are shown: arrangement of frame work approximate position of objects boundary lines base line proposed chain lines and station positions

5. What do you understand by (i) scale (ii) drawing to scale.

As survey work involved in a large area it is not feasible, to prepare the drawings in full-size. Thus it is necessary and for convenience the drawings have to be made to a reduced scale. This operation is known as drawing to scale.

Scale of a drawing may be defined as the ratio of the ground distance to the plotted length on the drawing sheet.

6. Give conventional signs for the following:

(i) Rough pasture, (ii) Cutting (iii) Barren land and (iv) Telephone post.

clip_image002

7. What is the principle of chain surveying?

The principle of chain surveying is based triangulation which' is to divide the area into a network; triangles which should be well conditioned. The sides of the triangles are measured directly on the field by chain or tape and no angular measurements are made.

8. What is meant by well-conditioned triangle?

A well-conditioned 'triangle is qne in which no included angle is less"than 30° or greater than. 120°. An equilateral triangle is the best conditioned triangle or an ideal triangleJ

clip_image004

9. Distinguish between survey station and tie station.

Survey station is a selected point on the chain line and ibe located either at the beginning of the chain line or at end. Tie stations are also subsidiary stations taken on the in survey lines.

10 What are the instruments used for a chain surveying

Following are the instruments used for chain survey. (i) Instruments for linear measurement: chain, tapes

(ii) Instruments for setting out right-angles: cross-staff, optical square and prism square

(iii) Other accessories: ranging rods, offset rods, arrows, plumb bob, wooden· pegs.

11. Distinguish between Metric chain an Engineer's chains.

Metric chains are available in length of 20 m or 30 m length. The 20 m chain is divided

into 100 links (0.2 m ), the 30 m chain is divided into 150 links (of 0.2 m) and tallies connected at every 10 links and 25 links respectively.

Engineer's chain -is 100 ft in length and divided into too links. The details of construction are the same as that of the metric chain. For every ten links brass tags are provided.

12. How do you test a chain?

One meter length of a chain should be accurate to 2 mm then measured by a standardized tape or steel band. The chain length may be of: (i) 20 m chain ± 5 m; 30 m chain ± 8 m. The chain is tested by comparing it with (i) a, standardized steel tape kept in a surveyor's office and (ii) the chain standard (standard chain length) kept at some public buildings in town.

13. What are the instruments used for a chain surveying

Following are the instruments used for chain survey.

Instruments for linear measurement: chain, tapes

Instruments for setting out right-angles: cross-staff, optical square and prism square

Other accessories: ranging rods, offset rods, arrows, plumb bob, wooden· pegs.

14. What are the instruments used for setting out right angles to a chain One?

Following are the instruments used for setting out right angles to a chain line.

Cross-staff: It is the simplest form of instrument used for setting out perpendiculars.

There are three types, viz., open cross-staff, French cross-staff, and Adjustable cross- staff.

Optical Square: It is a small metal box with mirrors and three slits to view and set out perpendiculars. The principle involved in the instrument is the principle of reflecting surfaces.

Prism square: It is based on the same principle as that of optical square. Here instead of prism is used. It is more versatile and reliable instrument.

15. What is Representative fraction?

Scale of a drawing is defined as the ratio of the ground distance to the plotted length on the drawing sheet, 1 cm = 10 m where 1 cm in a sheet representing 10 m on. Ground the above scale can also be represented as whose numerator is unit Y. This fraction is called Representative fraction (RF).

16. How do you record the field observation in a field book?

The field book consists of an oblong book with a hinge short-length edge. The chain is represented by one or red or blue lines printed centrally along the length of each e. The recording also called as booking, is commenced from bottom of the first page. In order to distinguish from the readings, the double-line book is preferred.

17. What is meant by hypotenusal allowance?

The allowance made in a measurement made on a peg ground to get the horizontal distance is called the hypotenusal allowance. This is given as 100 which is the angle of the slope.

18. What are the different Sources of errors in chain surveying?

The sources of errors in chain surveying are

Compensating. errors and

Cumulative errors.

19. What are the different tape corrections?

Tape corrections. are all made for one or more of the reasons, viz., temperature, pull, slope, sag and Temperature connection is made when the temperature the time of measurent till is different than the standard temperature to Correction may be positive or negative pending on Tm is

greater or less than to Similarly other corrections are made .

20. Explain the Graphical method of enlarging a map.

The figure to be enlarged or reduced to be taken and)" along the boundary a net work of squares of 2 cm to 5 cm side are accurately drawn of pencil. The vertical and horizontal sides are drawn on the complete figure. Next a similar number of squares are drawn, on drawing larger in size. The points of intersection of the lines in plan and the details with the sides of square and the exact location of the points- of the figure are carefully noted.

The noted points are transferred to new drawing after scaling proportionately. These points are joined by smooth curve which gives the enlarged figure

Part-B

1. a. Explain principal of Surveying.

(8)

b. With a simple sketch state the construction and use of a cross staff

(8)

2. a. Explain the principal of working from whole to part

(8)

b. What are the accessories for a chain survey? Explain the functions of each.

(8)

3. Discuss the various obstacles in chaining.

(16)

4. What is ranging? What are the methods of ranging a survey line?

(16)

5. a. Explain the method of reciprocal ranging.

(8)

b. Discuss the methods of chaining over obstacles for chaining and not for ranging

(8)

6. A Chain was tested and found exactly 30m before starting a survey. At the end of the (16)

chain survey, it was found to be 0.18 meter too long. The survey was for finding the

area of a field. The area of this field as drawn to scale of 1cm = 50meters was 130 Sq-m. Find correct area of the field?

7. A steel tape 30m long standardized at 100C with a pull of 10 kg was used for (16) measuring a base line. Find the correction per length, if at the time of measurement the temperature was 220Cand the pull exerted 15 kg weight of steel per cubic centimeter

equals 7.75 gms. Weight of tape is 0.68kgs, E=2.11 x 106 kgs/cm, and α = 12 x 10-6

per 0C.

8. A distance of 2000m was measured by 30m chain. Later on it was detected that the chain (16) Was 0.1m too long .Another 500m (i.e., total 2500m) was measured and it was detected

That the chain was 0.15m too long. If the length of the chain in the initial stage was correct , Determine the exact length that was measured.

9. What are different tape corrections and how are they applied? (16)

10. What are the different sources of error in chain surveying? Distinguish between cumulative

And compensating error (16)


UNIT-II

Part-A (2 Marks)

1. Define the following terms: (i) True meridian (ii) Magnetic meridian

The line passing through the geographical North Pole or the pole and any point on the surface of the earth is known the true meridian or geographical meridian. The direction shown by a magnetic needle without being affected by magnetic substances, when the needle is suspended and balanced properly is known as the magnetic meridian.

2. Define: (i) True bearing (ii) Magnetic bearing

True bearing of a line is the angle made by the line with the true or geographical north. It is always measured in the clockwise direction with a measuring range of 0° to 360°. Magnetic meridian of a line is the angle made by the line with the magnetic north. It is always measured in the clockwise direction with a measuring range of 0° to 360°.

3. Differentiate between "Surveyor's compass" and "Prismatic compass" with reference to reading and tripod.

With referenced to reading In Prismatic compass, the reflecting prism carries the

sighting and the sighting of the object and readings are taken simultaneously. Surveyors compass, the object has to be sighted to ground to read graduation and readings are With reference to tripod.

Tripod may or may not be needed for prismatic compass It can be used even by holding suitably in hand. . Surveyor's compass can not be used without a tripod.

4. What’s meant by reduced bearing?

When the whole circle bearing is converted to quadrates bearing it is termed the reduced bearing. Thus the reduced bearing is similar to quadrantal bearing.

5. The fore bearings of a line AB is 60°, and BC if. 340°. Calculate the angle ABC. If the back bearings. of CD and DA are 60° and 345° respectively, calculate the angles BCD and CDA. . Fore Bearing of AB = 60°

Back Bearing of AB = 240°

LA = F.B of BC ~ B.B of AB = 340° - 240° = 100

L.BCD= 240° - B.B of BC= 240° - 160° = 80

6. What are the different sources of local attraction?

The materials which may influence magnetic action are the presence of

Magnetic rocks

Iron ore deposits

Steel structures

Rail

Iron lamp posts

Transmission tower

7. Write the advantages of plane table surveying.

The plan is drawn at the field itself

The surveyor can compare the plotted work with actual features of the area.

Most suitable for small scale work

No great skill is required

8. Write the disadvantages of plane table surveying.

Most inconvenient in rainy season

It is inconvenient to transport.

It is not intended ended for specific work.

It is essentially a tropical instrument.

9. What is resection? List a few methods.

Resection method is used or establishing the plane table station. That is the significance of this method is that the point plotted on the map is the station occupied by the plane table. This method· is quite useful and is applied in the solution of two-point and three-point problem

.Three point problems can be solved by (i) mechanical method (ii) graphical method and (iii)

hit and trial method

10. List the errors in a plane table surveying.

Instrumental error

Errors of plotting

Errors due to manipulation and sighting

Inaccurate centering.

11. State Two point problem.

Location of the position on the plan , of the station occupied by the plane table by means of two observations to two well defined points whose position have been plotted on the plan.

12. State three point problem.

Location of the position , on the plan of the station occupied by the plane table by means of observations to three well defined points whose positions have been previously plotted on the plan.

13. What do you mean by strength of fix?

The accuracy of locating the position of a point, say A, is based on the relative position of points, say P, Q, R and A. If the station A lies on the great circle, all the three rays intersect at

one point although the plane table is not perfectly fixed. At this condition the required point (a) becomes indeterminate. For other positions of A triangle of error will be reflected. Under these conditions the accuracy of fixing the position of point a Varies with location of A relative to P, Q and R. The accuracy of fixing is designated as the strength of fix.

14. Distinguish between closed traverse and open traverse.

Closed traverse is one in which the last survey line is joined back to the last station point forming a polygon. Such a type of survey is more suitable for moderately large areas like lakes, forests, building complexes, etc.

Open traverse, also called as unclosed traverse is are, when the traverse does not return back to the first station point and does not form a closed polygon.

15. List the errors in a compass instrument.

The errors may be caused due to

needle not straight

pivot not upright

needle lost magnetism

pivot not sharp but dull

movement of the needle not free

plane of sight not vertical

graduation circle not horizontal

Plane of sight not passing through the graduated ring.

vertical hair is too thick or low

16. Distinguish between plain alidade and telescopic alidade.

The plain alidade is fitted with the vanes at each end which are hinged with the horse hair.

One vane is on object vane which is provided with a horse hair and the other one is a sight vane provided with a narrow slit.

The telescopic alidade provided with a telescope replaces the vanes and is meant for sighting inclined sights and sighting distant objects.

17. Why centering and leveling should be done?

Centering is the process by which the point on the ground and the point plotted on the drawing sheet are brought on the same vertical line. This is to be done only then points transferred from ground to the sheet will be correct and any object located will be accurate.

In the process of leveling the plane table is brought to the horizontal position with respect to the centre line of the table. Then only when the table is rotated for different observations, the plane will be horizontal and the points located will be exact. If not the location of points are distorted.

18. What is orientation? Why it is to be performed?

The table is so positioned such that all the lines plotted and parallel to the corresponding lines on the ground. This process is called orientation. The process connects all the ground stations and maintains the same position in the paper. Orientation is performed at every successive

station. Orientation can be done by back-sighting method or by using magnetic needle.

19. When would you recommend radiation method?

The radiation method is useful for surveys of small areas wherein all the objects can be commanded from a single plane table station. In large scale areas to be surveyed this method can be combined with other methods using a telescopic alidade. The work can be rapidly used and will have a wider scope.

20. What is intersection method? Where it is used?

In this method the objects are fixed on the plane table sheet by intersection of rays from two plane table or instrument stations. The line joining these two plane table stations is called the base line. This method needs only the measurements of the base line unlike in the radiation method.

Part-B (16Marks)

1. A compass survey was carried out around a closed traverse ABCD and the (16)

following readings were obtained:

LINE

F.B

B.B

AB

74º30’

256º10’

BC

107º30’

286º30’

CD

225º10’

45º10’

DA

306º50’

126º10’

Find out the station affected by the local attraction and work out the corrected bearing of the lines.

2. Find out the station affected by the local attraction and work out the corrected (16)

bearing of the lines. The following are the observed bearing of the lines of a

traverse ABCDEA with a compass in a place where local attraction was suspected.

LINE

FB

BB

AB

1910 45’

39030’

BC

22015’

222030’

CD

22015’

200030’

DE

242045’

62045’

clip_image005EA 330015’ 147045

Find the correct bearing of the line and included angles.

3. The following are the bearing observed in traversing with a compass an area where. (16) Local attraction was suspected Calculate the interior angles of the traverse and correct

Them if necessary.

LINE

FB

BB

AB

15000’

33000’

BC

230030’

4800’

CD

306015’

127045’

DE

2980

120000

EA

49030’

229030’

4. Explain briefly about three point problem of (16) (a) Beesels graphical method

(b) Trial and error method

5. a. Describe procedure of setting a plane table and orientation methods over (8)

a station

b. Distinguish between resection and intersection methods as applied to plane table surveying.

(8)

6. Describe the various accessories used in plane table surveying? Explain their (16) Functions?

7. a. Compare in detail a surveyor’s compass with a prismatic compass. (8)

b. Describe the method of orientation of plane table surveying. (8)

8. Draw a neat sketch and explain the prismatic compass (16)

9. What is a two point problem? How it is solved. (16)

10. Define three point problem and how it is solved by tracing paper method. (16)


UNIT –III

PART –A

1 What is Leveling?

Leveling is the operation of measuring vertical distance either directly or indirectly, to determine differences in elevation. The difference in elevation between two points is the vertical distance between the two level surfaces in which the points lie.

2. Define Bench-Mark.

It is a fixed point or mark of known elevation fixed \\lith reference to a datum line. They serve as reference points for finding the reduced level of new points or for conducting leveling operations in projects involving roads, railways. etc.

3. Name different kinds of bench marks.

GTS Bench-mark

Permanent Bench-mark

Arbitrary Bench-mark

Temporary Bench-mark

4. Distinguish between GTS Bench-mark and arbitrary Bench-mark.

GTS "Bench-marks are those bench-marks which are established all over the country at large intervals by the Survey of India. Department.

When reduced levels of some fixed points are assumed, they are called as arbitrary bench-mark. These are adopted in small survey operations.

5. Distinguish between Permanent and Temporary Bench-marks.

Permanent bench-marks are fixed points or marks set up by different Govt. departments. The, reduced levels of these points are determined with reference to GTS bench-marks.

When the bench-marks are set up temporarily at the end of a day's work, they are referred to as temporary bench-marks

6. What are back-sights and fore-sights?

Back sight is the first staff reading taken on a point of known elevation in any set up of the levelling instrument.

Foresight is the last staff reading taken a point in set up of the levelling instrument and indicates the shifting of the instrument.

7. Differentiate between a level line and a horizontal line.

Any line lying on a level surface is called a level line.

This line is perpendicular to the direction of gravity at,a points.

Any line lying on a horizontal plane is a horizontal line which is tangential to a level line. .

8. What is the difference between the line of collimation and axis of the telescope?

Line of collimation or line of sight is an imaginary line passing through the cross-hair at the diaphragm and the optical centre of the object glass and its continuation.

Axis of telescope is an imaginary line passing through the optical centre of the object glass and the optical centre of the eye-piece.

9. What is an R.L? How will you get the R.L of a starting point?

The reduced level or elevation in the vertical distance of a point above or below a datum. . The R.L. of. a point may be positive or negative according as the point is above or below the datum. R.L. of a first point is got by adding the back-sight reading taken on Bench-mark to the elevation of that Bench-mark.

10. How leveling is done using foot screws?

The telescope is placed parallel to, a pair, of foot, screws and the bubble is brought to the centre by turning both the screw inwards and outwards. Then the telescope is rotated

by 90° such that it lies over the third foot screw. This foot screw, only is turned now to bring the bubble to the centre. The telescope is brought back to the old position with the

object glass and eye-piece in the same position. The bubble is brought to its centre. Now the operation is repeated until the bubble remains at the centre

10. Explain the theory of simple leveling.

If it is required to find the difference in elevation between two points which are visible from simple positions, then the leveling performed is called the simple leveling. Let P and Q be the two points and the R.L of P be 100.00. Level is be set up at the middle of the points and the readings be 2.305 and 1.215 on the staff held at P and Q. Then,

RL of point P== 100.00

Height of instrument = 100 + 2.305 == 102.305

R.L. of point Q = 102.305 - 1.215 = 101.09

11. What is fly leveling?

Fly leveling in principle is at to differential leveling. Fly leveling is done to connect the bench-marks to any intermediate point of the alignment for checking the accuracy of the work. Here, back-sight and fore-sight readings are taken at every set up of the level and the level is set approximately at the midway between the' points.

12. What are the arithmetical checks done? In both the systems of reduction of levels?

Every page of a level book should end with a check on the entries and the reduction of levels, this check is called as arithmetical check. As per this check in

Plane of collimation method .Here there is no check on the R.L s. of intermediate points

Rise and Fall method

There is complete check on the R.L s of intermediate points

13. What are the errors in leveling?

Following are the errors:

Improper adjustment of level

Parallax error

Earth's curvature

Atmospheric refraction

Variation in temperature

Staff not held vertically

Faulty turning points

Settlement of tripod

Bubble not at the centre

Inability of the observer in reading

14. Define the terms (i) Contour line, (ii) Contour interval and (iii) Horizontal equivalent.

Contour Line: If the locations of several ground points of all elevation are plotted on a drawing a line joining these p6ints is called the contour line.

Contour Interval: On a given map, successive contour lines for present elevations. Differing by a fixed vertical distance called f the contour interval.

Horizontal Equivalent: The horizontal distance between any r to consecutive .contours is known as the horizontal equivalent and depends on the steepness of the ground.

15. How will you distinguish between a summit and a depression by studying the nature of the contour?

A closed contour line indicates either a summit or a depression according as the Higher or lower values are inside them. In summit the higher values are inside the closed contour and the lower values on the outer. In the depression the lower value is at the inside of the closed contour and the higher values on the outside.

16. How earthwork required is calculated using contours.

For computation of earthwork areas of cross-sections of successive cross-sections are considered. The average area, multiplied by the spacing between cross-sections gives the volume of earthwork. For this trapezoidal or prismoidal rules can be used.

17. Why the horizontal equivalent is not constant?

Horizontal equivalent is the horizontal distance between any two consecutive contours. Depending on the steepness or plain nature of the ground· the horizontal equivalent depends. For steeper slope the horizontal equivalent is less than a plain ground for the same difference in elevation. As the slope of the ground· between two contour is not constant in all directions, the horizontal equivalent is not constant.

18. In some contours the lines are closer in some they are wider for the same contour interval what does it mean.

Contours running close together indicate a slope for a given contour interval. For the same contour interval, they run wider in plain flat terrain.

19. What is contour gradient? Where it is used?

The gradient between any two contours .Is called the contour gradient. This is got by dividing the difference in elevation between two contours, at a point and the horizontal stance between them. This is used in route surveying.

20. Explain the object of preparing a contour map.

Generally topography of an area is depicted by a 'contour which are very useful for various engineering projects. As a matter of fact every civil engineering work has to be started (with a contour map. Contour maps are prepared for alignment of highway, railway, waterway, sewer line, etc and to decide the catchments, area of the reservoir and the location of a dam or reservoir.

PART – B

1. What are the temporary adjustments of dumpy level? How is it done? (16)

2. Following consecutive staffs reading were taken with a level along a sloping (16)

 

Ground line AB at a regular distance of 20m by using 4 m leveling staff

0.352,0.787,1.832,2.956,3.758,0.953,1.766,2.738,3.872,0.812,2.325and 3.137. Rule out a page of level field book, enter the above reading RL of point A is

320.288 Calculate RL of all points by rise fall system, and work out the gradient of line AB.

 

3.

Following is pages of spoiled field book complete it and show necessary

Check. Find the values in the ‘X’ marked column

(16)

B.S

I.S

F.S

RISE

FALL

R.L

2.430

       

150.000

 

X

   

0.320

X

3.210

 

1.040

1.710

 

X

 

2.415

 

X

 

X

 

3.575

   

X

X

2.150

 

X

2.615

 

X

 

3.670

   

X

X

     

X

2.550

X

4. The following consecutive reading were taken with a level and 4m leveling staff (16)

ground at common interval of 30m as

0.725 on A,0.935,2.845,3.745,3.935,0.965,1.135,1.785,2.625,3.845,0.965,1.575 and 2.015 on B. The elevation of point A is 220.50m. Makeup level book page, apply usual check and calculate the reduced levels of points. Also calculate the gradient of line AB.

5. The following is the extract of a page level field book. Fill in the missing reading (16)

and calculate R.Ls. Apply usual check :-

S.NO

B.S

I.S

F.S

H.C

R.L

REMARKS

1.

X

   

102.500

100.000

B.M

2.

 

3.205

   

X

 

3.

 

X

   

101.255

 

4.

2.815

 

1.970

 

X

 

5.

 

1.820

   

X

 

6.

 

X

   

99.825

 

7.

   

X

 

101.420

 

6. The following reciprocal levels were taken with one level: - (16)

INSTRUMENT

STATION

READING ON STAFF

HELD AT

A

B

A

2.180

2.715

B

1.300

1.615

Distance between A and B was 900 m. If R.L. of A is 230.00m Determine i) the true level of B ii) he combined correction for curvature and refraction.

7. What do you understand by sensitivity of bubble tube? How is it determined? (16) In a leveling work, following are the observation taken at every 30m interval

along a survey line. First reading was taken on zero chainage having R.L. =176.500

Enter these observations in proper tabular form, compute reduced levels and show necessary check. Determine the general gradient of ground from first point and the last point neglecting other points.1.750, 1.370, 1.150, 2.315, 0.950, 1.415, 2.040 and 3.590 Instrument was shifted after 4th observation.

8. The following reading were taken with a dumpy level 1) when the instrument is (16)

midway between two pegs A and B,100mts apart. The staff reading on A= 3.345m

The staff reading on B= 2.025m 2) When the instrument is kept very near A

The staff reading on A= 2.950m The staff reading on B= 2.000m Is the instrument in adjustment or not? When the instrument is very near A, What should be the correct reading on staff B?

9. Find the radius of curvature of the bubble tube if the length of one division is 2mm (16)

and if the angular value of one division is:

i) 20Second ii) 1minute

10. What is reciprocal leveling and why is it employed? What errors will be eliminated? (16)

by this?

11. Explain with neat sketches the characteristics of contours. (16)

12. Show contour to represent the following with neat sketches.

1) Valley 2) A Saddle 3) Vertical cliff 4) Hill

13. What are the methods of “Interpolation” of contour? Explain. (16)

14. Write Characteristics of Contour lines. (16)

15. What do you understand by Sensitivity of bubble tube? How is it determined? Find (16)

the radius of curvature of bubble tube if the length of one division is 2mm and if the angular value of one division is:1) 20 Second 2) 1minute.


UNIT- IV

Part-A (2 Marks)

1. What are consecutive coordinates and independent coordinates?

Consecutive coordinates are those in which the latitude and departures of a point life calculated with reference to the point. These coordinates may be positive or negative on the quadrant on which, it falls Independent coordinates are those in which the latitude departures of a point are calculated with respect to origin. The origin may be a survey station or a point outside the traverse.

2. Define latitude and departure.

The latitude of a line is the distance measured parallel the North-South line. Similarly the distance measured parallel to the East-West line is the departure. If the reduced bearing of a line and its length are known then the latitude and departure can be computed

3. What is Transit Rule?

In theodolite traversing the angular measurements are more accurately done compared to linear measurements. The transit rule is applicable only in such situations. As per this rule the correction to latitude or departure is considered as a factor of latitude or departure of the side instead of the length the side. Accordingly the transit rule is Total error in latitude Correction to departure.

4. What is Bowdich rule?

Bowdich rule is applied for corrections in latitude: and departure. As per this rule, the error is proportional to the length of the side. Therefore the corrections to the latitude and departure are given as closing error in latitude

5. Which method you prefer for open-traverse using theodolite?

The deflection angle method is mostly suitable for open-traverse in the survey of rivers, coast lines, roads, railways, etc. A deflection angle may be defined as the angle between the 'preceding survey line and the following line. The angle may be a right-hand deflection angle or the left-hand deflection angle based on the observation.

6. How traversing is done by adopting included angle method?

This method may be used for both open-traverse and closed-traverse. It is more suitable for closed- traverse. Although traverse may be done in clockwise or anticlockwise direction. For closed- traverse the traverse is generally taken in the anti-clockwise direction. It is necessary to note down whether the angle is interior angle or exterior angle.

7. Explain reiteration Method.

In this method all the horizontal angles are measured successively and finally the horizon is closed the angle the last and first station is measured. The final reading vernier should be the same as its initial reading. does not coincide, the 'difference is equally 'distributed i, e measured angles.

8 Explain the repetition method.

In this method the angle is added continuously and the total angle is divided into the number of repetitions to get the angle. Generally six repetitions are made, out of which half of the repetitions are made, out of which half of e repetitions are made with the telescope normal and half with the telescope inverted. By this process very accurate measurement of angles can be made.

9. What is called spire test?

The test conducted to bring the horizontal axis perpendicular to vertical axis is called the spire test. This condition ensures that the motion of telescope is in a vetiical plane.

10. What do you understand by the name transit theodolite?

Theodoltes are primarily classified as (i) Transit and (ii) Non-transit theodolite

Transit theodolite is one in which the telescope can be revolved through a complete revolution about its horizontal axis in a vertical plane. Transit theodolite is mostly used now-a. days.

11. Define standards in theodolite.

This is shaped like letter 'A' and also called as A frame which is the supporting telescope, top of the standards are provided with the bearings for the pivots of the telescope About these pivots the telescope can 'rotate freely in the vertical plane.

12. List the essential qualities of a theodolite telescope.

Internally focusing telescope is used in theodolites. In this telescope, the objective arid eye-piece do not move when the focusing screw is tuned. There is a double concave lens is fitted with rack and pinion arrangement between eye-piece and objective. This lens moves in and out when the focusing is done and a real image is formed on the plane of cross-hairs.

13. List the essential parts of a theodolite.

A transit theodolite consists of the following parts:

Leveling head

Plate levels

Lower plate

Telescope

upper plate

Altitude bubbles

Plumb bob

Compass

T-frame

14. What is a prismoidal formula for computation of volume? V=d/3 [A1+An + 4 (A2 +A4 + ... ) + 2 (A3 +A5+ ... )]

15. What is prismoidal correction for Trapezoidal Rule?

In general volumes between successive areas are found on the average of end areas and a prismoidal correction Prismoidal correction is deducted from the volume computed using average end areas. It varies with the type of, n involved.

16. What is a planimeter?

Planimeter is an instrument used for finding out the area plotted, plan. It is a mechanical device which is fast. The polar planimeter is the one which is widely used

17. State Trapezoidal rule? What are the limitations?

The trapezoidal rule may be stated as, the sum of the first and last ordinates; twice the sum of the intermediate ordinates and the total sum is multiplied by half of the common distance. Here the boundaries between the end of ordinates are assumed to be straight lines.

This can be applied to any number of ordinates. There is no limitation.

18. State Simpson's rule? What are the limitations?

The Simpson's rule may be stated as: The sum of the and last ordinates, four times the sum of the even ordinates twice the sum of the odd ordinates, multiplied by the non distance and divided by three. The boundaries between the ordinates are assumed to an arc of a parabola. The limitation of this rule is that it can be applied when lumber of ordinates is odd.

19. How area is calculated from a plan by dividing into squares?

A square chart of convenient size is plotted on a tracing per, with each square representing a definite area namely are cm. or square meter.

The tracing paper is placed on the drawing sheet or map I the number of full squares are first counted. The portion the squares on the boundary are broken which are estimated terms of fractional squares. The required area is calculated

20. What is called area of skeleton? Give examples.

In the process of surveying the whole area is divided to some geometrical figures, such as triangles, rectangles, squares, and trapeziums and then the areas are calculated by e known geometric formulae.

PART – B

1.

Describe the process of repetition and reiteration method of Theodolite traversing

(16)

2.

What are the different fundamental axes of theodolite and list out the relation between them?

(16)

3. Explain, how to determine R.L. of the Elevated object as base of the object inaccessible and instrument station are in the same vertical plane as that of the elevated object and

also instrument axes at the same level in case of trigonometric leveling.

4. An observer standing on the deck of a ship just sees a light house. The top of the light

(16)

house is 40mts above the sea level and height of the observer’s eye is 5mt above the sea level. Find the distance of the observer from the light house. (16)

5. Explain the terms:

1) Latitude

2) Departure

3) Consecutive Coordinate

4) Independent Coordinate (16)

6. A theodolite was setup a distance of 180m from a light house and the angle of elevation to its top and depression to its base were observed as 22º45’ and 1º12’

respectively. The reading on a staff held on B.M. of R.L. 175.590m.was 1.85m

with line of collimation horizontal. Calculate 1) The height of light house

2) The R.L of top.

(16)

5.

Write short note on temporary adjustment of theodolite.

(16)

7.

Draw a neat diagram of transit theodolite and label its parts.

(16)

8.

The following are the length and bearings of the sides of a closed traverse ABCD:-

Line

Length (m)

Beearings

AB

76.80

140012’

BC

195.60

36024’

CD

37.30

338048’

DA

?

?

Compute the length and bearing of the line DA. (16)

9. A traverse was made along three lines AB,BC, CD And the result tabulated as follows:-

Line

W.C.B

Incl.Angle

Length (m)

AB

16700’

 

216.7

BC

 

12600’

176

CD

 

11500’

295.5

DA

 

?

?

Calculate the length and bearing of DA. (16)

10. Due to certain obstruction in running a traverse ABCDEA, the length and bearing of

the line CD could not be taken. The following measurements were taken. Calculate the length and bearing of the line CD:- (16)


UNIT- V

Part-A (2 Marks)

1. What is mine surveying?

The principle of mine surveying, also generally called as underground survey, is similar to those of land survey but for some difference. Special considerations are given for the following important factors.

arrangements to be made to illuminate the target.

placing stations on roof should be visible

adequate care in shaft plumbing

underground traverse to be done through different passages.

proper coordination of various works have to be done.

2. What is a construction survey?

The purpose of construction survey is to re-establish points, lines and grades. On the ground at the time of construction. Any minor modifications can be accommodated from the location survey. Any additional precautions or techniques to be adopted may be done during the construction stage.

3. How the setting out of a culvert is done?

In order to facilitate a roadway or a railway or pipeline proceed crossing a null or a steam a culvert is constructed,

The centre of the culvert is taken as the origin of a angular coordinate system. The centre line of road or railway is considered as one axis and the centre line of stream is considered as another axis. The foundation centre line diagram is prepared and the centre line portion of stream is also prepared. The centre lines are mark as done in a building and then proceeded.

4. What are the local surveys to be conducted for a highway project? The detailed survey involved is:

fixing temporary bench-marks along the route for every 300 m.

the cross-sectional details are taken for every 30 m on either side of the centre line.

All details of cross-drainage works are taken

Topographical details are taken

Detailed soil survey is carried out

5. What are tunnels?

Tunnels are underground passages or routes used for different purposes. They are made by excavation of tacks below the surface or through the hills or mountains. In the election of location of tunnels various factors like location of ,am, power house, nature of bus routes, location of township, etc are to be considered like other engineering structures and tunnels too need favourable geological conditions t the selected site for achieving safety, stability and econ0It;ty.

6. What is a route surveying?

Route surveying is applied to the surveys required to establish the horizontal and vertical alignments for transport facilities. The transport facilities may be a highway, railway, aqueducts,

canals, water pipe line, oil and gas line, cable ways, ;sewage disposal, power, telephone and transmission lines.

7. List the details to be taken in a location survey in anyone project.

Following are the details to be taken in a location survey a canal-irrigation project:

Pattern of rainfalI over the year.

types of crops

water demand for each type of crop

adequacy of rainfall

Future scope of the project, etc.

8. What preliminary surveys are done for establishing an airport?

The preliminary survey includes the following surveys:

A theodolite transverse is done covering the entire area

A plane table survey is carried out to get the details.

If it is a rugged terrain and unsuitable to conduct a chain survey, a tachometer survey .may be conducted.

A proper location survey has to be conducted to decide the place for communication tower.

A contour survey has to be conducted to locate the runways and taxiways.

9. List the names of instruments needed in a preliminary survey.

The following instruments are generally used for preliminary survey:

transit theodolite

prismatic compass

Dumpy level or hand level or Abney level

chain and accessories

tapes

plane table

10. What are the details to be taken in a reconnaissance survey for a triangulation project?

In the case of a triangulation project the reconnaissance survey consists of selection of stations. determination of the size and shape of the resulting triangles. The number of stations to be occupied and the number of angle or directions to be observed. Further the indivisibility and accessibility of stations and the convenience of baseline measurements are to be considered.

11. What are the three classes of circular curves?

The three types of circular curves are

a simple horizontal curve of single radius

a compound curve of two circular curves of different radii with common tangent.

a circular reverse curve of different or equal radii bending in opposite directions.

12. In a highway a change in the rate of grade or direction

may cause the vehicle on the highway a sudden impact. So for a smooth and safe running of vehicles on a change in gradient or direction condition a vertical curve is used. A vertical curve may be parabolic or circular curve. A parabolic curve is preferred as it provides a smooth and most comfortable ride.

13. What is an ideal transition curve?

The main requirement of an ideal transition curve is that the super-elevation should be increased informal with the increase of centrifugal force at a constant rate.

14. What is super-elevation?

When a vehicle is negotiating a curve that is suddenly .moving from a straight to a curved path, the vehicle experiences a centrifugal force which tends to push the vehicle away from the road or track. In order to counter-balance the centrifugal force the outer edge of a road or rail is raised which is known as the super-elevation or cant.

15. What are the functions of a transition curve?

Following are the functions of a transition curve:

should introduce super-elevation gradually

should maintain a constant proportionality between super-elevation and rate of change of

curvature.

should minimize wear and tear on rail section and on vehicle tires.

should eliminate derailment or over turning of train.

16. What is called two-theodolite method?

In this method of setting out curves two theodolites are used and hence the method is called "Two-theodolite method". In this method no tape or chain is needed. This method is suitable in terrains where the tape or chain could not be used.

In this method the basic property of the circle that "the angle between a tangent and the chord is equal to the angle hat the chord subtends in the opposite segment is used.

17. What is a transition curve and where such provided?

A curve having a gradual varying radius is called a transition curve. For example a curve with infinite radius in the beginning and varying gradually to a finite radius. Transition curves are provided in railway tracks to ensure safe running of the trains without overturning or derailment. This curves provide comfort to passengers both on roads and on railways.

18. What is a reverse curve? Where it is used?

When two curves of different or equal radii are bending in opposite directions then it is called a reverse curve, Reverse curves have one common tangent.

Such curves are preferred in situations where the straights have their angle of intersection is too acute. This is used in roads and railways where a low speed is anticipated.

19. What is a compound curve? Where it is used?

When a curve consists of more than one radius connecting two intersecting straights it is called a compound curve. The direction of change of curvature is on the same side.

It is used in situation where it is not possible to connect the two tangents by one circular curve, it becomes necessary, to take a common tangent, and set out two curves of different radii to connect the rear and forward tangents.

Part –B

1.a. Define lift and lead. (4)

b. Explain the operations involved in tunnel alignment and setting of tunnel. (12)

1. A simple curve is to have a radius of 300m. The tangents intersect at chainage (16)

of 1192.00m, and the deflection angle at intersection is 50.50 . Find the angent distance, change at beginning and a length of long chord , degree of curve and the number of full and sub chords.

3. a. What is a need for super elevation (4)

b. A transition curve is required fir a circular curve of radius 400m, the gauge (12)

being 1.5m between rail centers and maximum curve super elevation is restricted to 12.cm . The transition curve is to be designed for a velocity such that no lateral pressure is impressed on the rails and the rate of gain of radial and the rate of gain of radial acceleration is 30 cm/sec2. Calculate the required length of transition

curve and the design period.

4. a. Distinguish between a compound curve and a reverse curve. (4)

b. A parabolic vertical curve is to be set out connecting twouniform grades +0.8% (12) The transition curve is to be designed for a velocity such that no lateral

pressure is impressed on th rails and the rate of of gain of radial acceleration is

30cm/sec2. Calculate the length of transition curve and the design period.

5. a. A transition curve of 100m length is introduced on either side of a circular curve of

radius 500m .Calculate the shift and spiral angle. (10)

b. What are the factors to be considered in mine surveying? (6)

6a. Explain the procedure of setting out foundation trenches for buildings with masonary walls. (8)

b. Briefly explain the method of setting out a simple curve by offset from the chords produced. (8)

7. Draw a simple circular curve and mark the salient points. Explain the setting out of

curve by two theodolite method. (16)

8. Compare the difficulties involved in mine surveying with a normal surveying

Work or ground

(16)

9. Distinguish between a compound curve and a reverse curve.

(16)

10. Explain any linear two linear methods of setting out circular curves

(16)

CE2204 - Surveying– I Two Mark with Answers

Anna University

CE 2204 – SURVEYING-I

Question Bank with answers


UNIT I

INDRODUCTION AND CHAIN SURVEYING

1. Define Surveying. What are the fundamental principles of surveying?

Surveying is an art of determining the relative positions of various points on, above or below the surface of the earth by means of direct or indirect measurement of distance, direction and elevation.

The principles of surveying are:

(i). Working from whole to part.

(ii). To locate a new station by at least two measurements (angular, linear) from fixed reference points.

2. What is the object or purpose of surveying?

The primary object of surveying is to prepare a plan or map to show the relative position of the objects on the surface of the earth. It is also used to determine the areas, volumes and other related quantities.

3. Name the different ways of classification of surveys.

a. Primary classification

(i). Plane surveying

(ii). Geodetic surveying.

b. Secondary classification

(i). Based on instruments used

(ii). Based on methods.

(iii). Based on object

(iv). Based on nature of the field

4. Differentiate between plane and geodetic surveying.

Sl.No.

Plane surveying

Geodetic surveying.

1.

The curvature of the earth is

The curvature of the earth is taken.

.

2.

A line joining any two points is

A line joining any two points is

considered straight.

considered as curved line.

3.

The triangle formed by any three

The triangle formed by any three

points is considered as plane

points is considered as spherical

triangle.

triangle.

4.

It is done on a area less than 250

It is done on a area greater than 250

Km 2

Km 2

5. Classify surveying based on the equipments.

1. Chain surveying

2. Compass surveying

3. Plane table surveying

4. Theodolite surveying

5. Tacheometric surveying

6. Photogram metric surveying

7. Aerial surveying

6. Explain the constructions of a diagonal scale.

For a given short length ( PQ=PR), draw a right angle triangle. Its base( PR) and height (PQ) are equal. A short length is divided into a number of parts by using the principle of similar triangles in which like sides are proportional.

Thus,

1-1 represents 1/ 10 PQ

9-9 represents 9/ 10 PQ

7. Define chain surveying. What is the fundamental principle of chain surveying?

Chain surveying is the type of surveying in which only linear measurements are made in the field.

8.What is a well-conditioned triangle? What is its specific advantage? .

A said to be well- conditioned or well proportioned when it

9. What are the operations involved in chain survey?

(i). Ranging: The process of locating intermediate points on a straight line between two end points in a straight line.

(ii). Chaining: The process of measuring the distance with a chain or tape.

(iii). Offsetting: The process of measuring the lateral distance of the object from the survey line to the left or right according to their positions.

10. What are the instruments required for a chain survey?

Chain or tape, Arrows, Pegs, Ranging rods, Offset rods, Laths or whites, Plumb bob, Cross staff and Mallet.

11. Write the different types of Chain.

(i). Metric chain

(ii). Non-Metric chain

(a).Gunter’s chain or Surveyor’s chain

(b). Engineer’s chain

(c). Revenue chain

(d). Steel band.

12. Differentiate between Gunter’s chain and Engineer’s Chain

Sl.No.

Gunter’s chain or Surveyor’s chain

Engineer’s chain

1.

It is 66 feet long and divided in to 100

It is 100 feet long and divided in

 

links. 1link = 0.66 feet

to 100 links. 1link = 1 feet

2.

Measurements are in miles and furlongs.

Measurements are in feet and

   

decimals

13. Define: (a).Main stations.

Main station is a prominent point on the chain line and can be either at

the beginning of the chain line or at the end or along the boundary.

(b). Subsidiary stations:

The stations located on the main survey lines are known as Subsidiary

stations.

(c). Tie stations:

These are also subsidiary stations taken on the main survey lines to locate

the details of the object.

14. Distinguish between a check line and a tie line.

Sl.No

Check line

Tie line

1.

Check lines or Proof lines are the

The main object of running a tie line

lines which are run in the field to

is to take the details of the objects.

check the accuracy of the work

2.

The length of the check line

Tie line is a line which joints

measured in the field must agree

subsidiary stations or tie stations on

with its length of the plan.

the main line.

clip_image001clip_image002

15. What are the instruments used for setting out right angles to a chain line?

(i). Cross staff.

a. Open cross staff

b. French cross staff

c. Adjustable cross staff (ii). Optical square.

(iii). Prism square (iv). Site square.

16. What are offsets? Classify them.

An offset is the lateral distance of an object or ground feature measured from a survey line. The two types of offsets are,

(i). Perpendicular offset: The angle of offset from a point on a chain line is 900.

(ii). Oblique offset: When the angle of offset is other than 900 .

clip_image003clip_image004clip_image006

Perpendicular offset Oblique offset

17. What is the use of a line Ranger?

The line Ranger is a small reflecting instrument used for fixing com intermediate points on the chain lines. Without going to either end, we can fix the intermediate . points.

18. What are the stages of fieldwork in chain surveying? Or What are the steps involved in chain survey?

1.

Reconnaissance: It is the preliminary inspection of the area to be surveyed.

2.

Marking and fixing Survey lines.

3.

Running survey lines.

4.

Taking Offsets.

19. What are the different ape corrections?

1.

Correction for absolute length or standardisation.

2.

Correction for temperature.

3.

Correction for pull or tension.

4. Correction for sag. (- ve)

5.

Correction for slope. (- ve)

20. What are the errors in chaining?

(i). Compensating Errors: Which are liable to occur in either direction and tend to compensate.

(ii). Cumulative Errors: Which occur in the same direction and tend to add or subtract. It may be positive (measured lengths more than the actual length) or negative (measured lengths less than the actual length).

21. What are the different sources of errors in chain surveying?

(i). Instrumental errors: incorrect length of the chain (Cumulative Errors).

5

(ii). Personal error: Bad ranging (Cumulative Errors). Careless holding (Compensating Errors). Bad straightening (Cumulative Errors). Non- horizontality (Cumulative Errors). Sag in chain (Cumulative Errors). Miscounting and misreading and booking.

(ii). Natural Errors: Variation in temperature. (Cumulative Errors).

22. Enumerate the instruments used for measurement of lengths of survey lines.

(i). Chain or tape. (ii). Passometer. (iii). Pedometer (iv). Odometer

(v). Speedometer.

6


UNIT II

COMPASS SURVEYING AND PLANE TABLE SURVEYING

1. Define: Compass surveying. What are the objects of compass surveying?

Compass surveying is the type of surveying in which the direction of the survey lines are measured with a compass and the length of the survey lines are measured with a tape or chain in the field.

2. Write the names of the instruments used in chain surveying.

(i). Instruments for the direct measurement of directions: 1. Surveyor’s compass.

2. Prismatic compass.

(ii).Instruments for the measurement of angles: 1. Sextant.

2. Theodolite.

3. Define: (a). True meridian and bearing. True meridian:

The line or plane passing through the geographical North Pole, South Pole and any point on the surface of the earth, is known as true meridian or geographical meridian. True meridian at a point is constant.

True bearing:

The angle between the true meridian and a survey line is known as true bearing or Azimuth of the line.

(b). Magnetic meridian . and Bearing.

Magnetic meridian :

Magnetic meridian at a point is the direction indicated by freely suspended, properly balanced and unaffected magnetic needle at that point.

Magnetic Bearing:

The angle between the magnetic meridian and a survey line is known as magnetic bearing or bearing .of the line. It changes with time.

4. What do you understand by Whole circle bearing and quadrantal bearing of a line? Magnetic Bearings are designated by Whole circle bearing system and

quadrantal bearing system.

In Whole circle bearing system (WCB), the bearing of the line is measured with magnetic north in clockwise direction. It varies from 00 to 3600.

In quadrantal bearing system (Q.B or R.B) the bearing of the line is measured eastward or westward from north or south, whichever is nearer. The directions can be either clockwise or anticlockwise. It varies from 00 to 900.

7

5. Convert the whole circle bearing into reduced bearing: 500, 1760, 2100, 2320, 1500, 760,

3100 ,2420.

Whole circle bearing

Reduced bearing

WCB

RB

500

N 500 E.

1760

S (1800

1760)E = S 40 E

2100

S (2100

1800)W = S 300 W

2320

S (2320

1800)W = S 520 W

1500

S (1800

1500) E = S 300 E

760

N 760 E

3100

N (3600 – 3100) W = N 50 0 W

2420

S (2420

1800)W = S 620 W

reading and tripod.

SI.No.

Item

Prismatic compass

Surveyor’s compass

1.

Reading

(i). The reading is taken with a

(i). The reading is taken by

help of prism provided at the eye

directly seeing through the top of

slit.

the glass.

(ii). Sighting and reading taking

(ii). Sighting and reading taking

rejinpaul

can be done simultaneously from

cannot be done simultaneously

one position of the observer.

from one position of the

observer.

2.

Tripod

Tripod may or may not be

The instrument cannot be used

provided.

without a tripod.

clip_image007clip_image007[1]6. Differentiate between Prismatic compass and Surveyor’s compass with reference to

7. The fore bearing of a line PQ is N 280 W. What is its back bearing?

In quadrantal bearing (RB) system, the FB and BB are numerically equal but the quadrants are just opposite.

The FB of a line PQ is N 280 W, Then its BB is S 280 E .

8. Define: Fore and Back bearing.

The bearing of a line is measured in the direction of the progress of the survey is called the fore bearing of the (FB) line.

The bearing of a line is measured in the direction opposite to the survey is called the back bearing of the (BB) line.

BB = FB + 180 0 . (FB greater than 180 0, use - sign) (FB smaller than 180 0, use + sign)

9. The fore bearing of line AB is 155025’20”. Identify the back bearing of the line AB in

quadrantal system.

The fore bearing of line AB = 155025’20”. The back bearing of line AB , BB = FB + 180 0

= 155025’20” + 180 0

= 335025’20” (WCB)

= N (3600 – 335025’20”) W

= N 24034’ 40’’ W

10. Define and distinguish between magnetic dip and magnetic declination.

Magnetic dip:

Due to the magnetic influence of the earth, the needle does not remain in the balanced position. This inclination of the needle with the horizontal is known as the dip of the magnetic needle. To balance the dip of the needle, a rider (brass or silver coil) is provided along with it. .

Magnetic declination:

The magnetic meridian of a place is variable one due to some local attractive forces. Therefore, the true meridian and the magnetic meridian at a place do not coincide.

The horizontal angle between the magnetic meridian and the true meridian is known as magnetic declination.

11. The magnetic bearing . of a line is 48024’. Calculate the true bearing if the magnetic declinations are 5038’ East and 50 38’ West.

True bearing = Magnetic bearing + Eastern magnetic declination

= 48024’ + 5038’ = 54002’.

True bearing = Magnetic bearing - Western magnetic declination

= 48024’ - 5038’

= 42046’.

13. The magnetic bearing of a line is S 28030’ E. Calculate the true bearing if the magnetic declinations are 5038’ East and 50 38’ West.

Convert the reduced bearing into Whole circle bearing. Magnetic bearing = S 28030’ E. (RB)

= 1800 - 28030’ = 1510 300 .

9

True bearing = Magnetic bearing + Eastern magnetic declination = 151030’ + 7030’

= 159000’. (WCB)

= S(1800-159000’)E (RB)

= S 21 0 E .

True bearing = Magnetic bearing - Western magnetic declination

= 151030’ - 7030’

= 144000’. (WCB)

= S(1800-144000’)E (RB)

= S 36 0 E.

14. What is local attraction? What are the sources of local attractions?

Local attraction is a term used to denote any influence, such as magnetic substances, which prevents the needle from pointing to the magnetic north in a given locality.

The sources of local attractions are : magnetite in the ground, wire carrying electric current, steel structures, rails, underground iron pipes, chain etc.,

14. Distinguish between closed traverse and open traverse.

SI.No.

Closed traverse

Open traverse

1.

When the lines form a circuit, which

If the circuit ends elsewhere,.it is

ends at the starting point, it is known

known as open traverse.

as closed traverse.

2.

It is suitable for locating the

It is suitable for surveying a long

boundaries of lakes, woods etc,.

narrow strip of land required for

road canal etc,.

3.

Check:

No direct check on angular

Sum of interior angles = (2n – 4) 90

measurements.

Sum of exterior angles = (2n +4) 90

Where, n= number of sides of the

traverse.

15. What is plane table surveying? When is it preferred? Write its principle.

Plane tabling is the graphical method of surveying in which the field

observations and plotting proceed simultaneously.

It is mainly suitable for filling the interior details between the control stations

and also in magnetic areas.

The

main principle of plane table

surveying is that the lines joining

the

clip_image008clip_image009clip_image009[1]

points on the plane table are made to lie parallel to the corresponding lines joining the points on the ground while working at each station.

16. Name four methods of plane surveying.

1. Radiation

10

2. Intersection.

3. Traversing

4. Resection.

(i). Resection after orientation by compass.

(ii). Resection after orientation by back sighting.

(iii). Resection after orientation by three point problem.

a. Mechanical method.(Tracing paper method)

b. Graphical method. ( Bessel’s method)

c. Lehman’s method. (Trial and error method) (iv). Resection after orientation by two point problem

17. When a three- point problem resorted to in plane table surveying?

It is the method of orientation when the table occupies a position not yet located on the drawing sheet.

This method is employed when during surveying the surveyor feels that some important details can be plotted easily by choosing any stations.

18. State the First and second Lehman’s rule.

First rule: The distance of the point “p” (position of plane table on the

drawing sheet) to be fixed from each rays Aa (paper a, to ground A),

Bb (paper ,b to

ground B) and Cc (paper c, to ground C) is proportional to the respective.distancescomof the

stations A, B and C from the ground station P.

Second rule: While looking towards the stations the point “p” to be fixed, will

be either to the left or to the right of each of the rays.

19. What are the Advantages of plane table surveying?

1.

It is useful in magnetic areas.

2.

It is cheaper than the theodolite surveying.

3.

It is most suitable for small-scale maps.

4.

The surveyor can compare plotted work with the actual features.

20. Name some of the errors in plane tabling.

1.

Instrumental error.

2.

Errors of plotting

3.

Errors due to manipulation and sighting.

1.

Non horizontality of the board.

2.

Defective sighting.

3.

Defective orientation.

4.

Movement of board between sights.

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UNIT III

LEVELLING AND APPLICATIONS

1. Define Levelling. What are the uses of leveling?

Levelling is a branch of surveying, the object of which is; (i). To find the elevations of given points with respect to a given or assumed datum, and (ii). To establish points at a given elevation or at different elevations with respect to a given or assumed datum.

2. Define benchmark and reduced level. Benchmark:

Benchmark is a relatively permanent point of reference whose elevation with respect to some assumed datum is known.

Reduced level or Elevation:

The vertical distance of a point above or below the datum is known as the elevation or R.L of that point. R.L of a point may be positive or negative according as the point is above or below the datum.

3. What are the different kinds of bench marks?

A BM is the reference point of known elevation. It may be classified into

(i).G.T.S Bench Mark: The great trigonometrical survey (G.T.S) bench marks are established by the survey of India throughout the country. The levels of this

bench marks are established very accurately at a large interval with respect to the mean sea level at Bombay port.

(ii). Permanent . Bench Mark: These are established by different Government departments like PWD, Railways, Irrigation etc,. The RL of these points are determined

with reference to the G.T.S Bench Marks. Points on rocks, culvert, gate pillars, etc,.

(iii).Temporary Bench Mark: These are established temporarily whenever required. These are generally chosen to close the day’s work and to start the next days. Points on roofs, walls, basements, etc,.

(iv). Arbitrary Bench Mark: When the RL of some fixed points are assumed, they are termed arbitrary benchmark.

4. What do you mean by datum surface?

It is any surface, to which elevations are taken as a reference for the determination of elevations of various points. In India the datum adopted for the great trigonometrical survey (G.T.S) is the mean sea level at Bombay port.

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5. What is mean by line of collimation and height of collimation?

Line of collimation (Line of sight): It is an imaginary line passing through the intersection of the cross hairs at the diaphragm and the optical centre of the object glass and its continuation.

Height of collimation(HOC): The elevation of the Line of collimation (Line of sight) is known as Height of collimation. HOC = RL of BM + BS.

6. Write the different types of levels.

1. Dumpy level

2. Tilting level

3. Quick setting level.

4. Y-level.

5. Reversible level.

6. Automatic level

7. Lazer level.

7. List the essential parts of a Level.

Telescope, Eyepiece, Objective

Focusing screws. Longitudinal bubble

Foot screws, Upper parallel plate ( Tribrach), Foot plate( Trivet). Diaphragm adjusting screws, Bubble adjusting screws, Tripod.

8. What are the different type’s leveling staffs?

1. Target Staff

2. Self reading Staff.

a. Solid Staff

b. Folding Staff

c. TelescopicStaff.

9. Define and distinguish between ‘Back sights’ and ‘Fore sight’ in the process of fly

Levelling.

SI.No

Back sights (BS)

Fore sight

(FS)

1.

This is the first staff reading taken

This is the last staff reading

in any setup of the instrument. It is

taken in any setup of the

always taken on a point of known

instrument

and,

after

that

elevation( BM).

instrument is shifted.

2.

It is used to determine the height

It is used to determine the

of the instrument.

elevation (RL) of the staff

HI = known RL + BS

station.

RL = HI – FS.

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Anna University, Chennai