What is bench mark? State the types of bench mark and explain any one type.

What is bench mark? State the types of bench mark and explain any one type.
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1 Answer

Answer :

Bench Mark- It is fixed reference point of known or assumed elevation.

Types of bench mark1. Great trignometrical survey bench mark

2. Permanent bench mark

3. Arbitrary bench mark

4. Temporary bench mark

1.Great trignometrical survey bench mark-

 a. These are the bench marks established with very high precision at regular intervals by survey of India Dept. all over the country

 b. Their positions and bench mark values with respect to the mean sea level at Karachi are given in catalogue formed by department. They are also known as G.T.S. Bench mark
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Description : Explain importance of Bench mark in leveling and state the types of Bench mark. 

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Description : Define Ranging. State types of ranging.

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Description : Write three types of obstacles in chaining with examples. 

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State and explain temporary adjustments of dumpy level.

Description : State and explain temporary adjustments of dumpy level.

Last Answer : 1. Setting up the level. a. The level fixed on tripod. b. The legs of tripod stand are well spread so that the level will remain stable on tripod. c. Bring all the three foot screws ... screw till the image is distinct and clear. The cross hair on the diaphragm should also be seen clearly. 

Explain the temporary adjustments of prismatic compass.

Description : Explain the temporary adjustments of prismatic compass.

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Describe with neat sketch, the optical square and explain its principle.

Description : Describe with neat sketch, the optical square and explain its principle.

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What are offsets? How are they taken and recorded? Explain with sketch.

Description : What are offsets? How are they taken and recorded? Explain with sketch.

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Last Answer : Explanation : 1. First the back sight reading is taken on floor level whose RL is known to us; from which RL of instrument axis can be find out by adding RL of BM and BS reading. 2. Now ... staff reading. 4. Finally height of chajja is calculated as RL of slab bottom -  RL of floor top.

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Description : Explain temporary adjustment.

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Draw sketch and explain method of traversing of plane table surveying.

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Description : Explain how will you overcome the obstacles over river during chaining operation.

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Description : Explain errors occurred due to manipulation and sighting in plane tabling.

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Explain the radiation method of plane table survey with neat sketch.

Description : Explain the radiation method of plane table survey with neat sketch. 

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Explain dip of magnetic needle with neat sketch.

Description : Explain dip of magnetic needle with neat sketch. 

Last Answer : i) The inclination of the magnetic needle with the horizontal is called as magnetic dip of the needle. ii) Ordinary needle if perfectly balanced on pivot, remains in horizontal position. But when the needle ... sliding weight is attached on the side of the needle which is at higher position.  

Explain reciprocal ranging with neat sketch.

Description : Explain reciprocal ranging with neat sketch. 

Last Answer : Reciprocal ranging is done when ends of survey line are not intervisible due to hill intervening or ends of survey line are at far distance apart. Step wise procedure reciprocal ranging: 1. Let A and B be ... chained. 8. This method can also be used in ranging a line across a valley.  

Explain Direct method of chaining on sloping ground with neat skeetch.

Description : Explain Direct method of chaining on sloping ground with neat skeetch. 

Last Answer : While chaining on sloping ground, the horizontal distances can be computed by direct method i.e. By stepping. By stepping: It consist in measuring the distance in small horizontal lengths (e.g.L1). Let ... is continued in the correct line with point B. Then length of line AB=L1 +L2 +L3+L4

Explain the procedure for profile leveling with neat sketch.

Description : Explain the procedure for profile leveling with neat sketch. 

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Explain Graphical adjustment of closing error in a closed traverse.

Description : Explain Graphical adjustment of closing error in a closed traverse.  

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Explain ‘Intersection Method’ of plane table surveying with neat sketch. Also give situation when intersection method is used.

Description : Explain ‘Intersection Method’ of plane table surveying with neat sketch. Also give situation when intersection method is used.

Last Answer : 1. Lay out a base line AB and measure it and Plot a distance ab' on sheet using any scale. 2.Set up instrument at A' with a' over A' 3.Orient the table by placing alidade ... the case of the survey of mountainous country. 5. The only linear measurement required is that of a base line.

Explain Procedure for chain and compass traversing.

Description : Explain Procedure for chain and compass traversing.

Last Answer : Chain and compass traversing : 1) Reconnaissance of the area to be surveyed is done. 2) Traverse stations are fixed. 3) The F.B and B.B of the traverse are measured by prismatic compass and ... occur when the traverse is plotted. 6) This error is adjusted graphically by using Bowditch Rule'. 

Explain Orientation of plane table by Back-sighting Method.

Description : Explain Orientation of plane table by Back-sighting Method.

Last Answer : Ans:- The method of setting up the plane table at each of the successive stations parallel to the position it occupied at the starting station is known as an Orientation. Orientation must be done when ... and bisection of the ranging rod at a are perfect then orientation is said to perfect.  

Explain principle of chain surveying

Description : Explain principle of chain surveying 

Last Answer : 1) Principle of chain surveying is triangulation 2) Triangulation consists of frame work of triangles. The whole area is divided into network of triangles. 3) A triangle is the only simple plane ... to be adopted depends upon the shape & configuration of the ground & the natural obstacles. 

Explain indirect ranging with neat sketch

Description : Explain indirect ranging with neat sketch

Last Answer : Step wise procedure indirect ranging i.e. reciprocal ranging- Let A and B be the two station with rising ground or a hill intervening between them even i)Select any two intermediate station say M1 and N1 ... there position will be changed until finally they are both on the line A B exactly.  

Explain the procedure of profile leveling for construction of road.

Description : Explain the procedure of profile leveling for construction of road.

Last Answer : The operation of taking levels along the center line of any alignment at regular interval is called longitudinal or profile leveling. Along the alignment, spots are marked at regular interval along ... points are plotted against their chainage to obtain ground profile along the alignment.

Explain with neat sketch the procedure of radiation method of plane tabling.

Description : Explain with neat sketch the procedure of radiation method of plane tabling.

Last Answer : 1. The table is set at suitable station e.g. P from where all stations can be sighted and measured. 2. After centering and leveling, mark station P as P' on sheet. 3. Suppose stations A, B, C, and D are ... marked as pa. 5. Similarly station B, C and D are bisected and marked as b, c and d.

Explain with neat sketch graphical adjustment of closing error.

Description : Explain with neat sketch graphical adjustment of closing error.

Last Answer : Procedure: 1. Plot the traverse e.g. A'BCDEA to suitable scale and obtain magnitude and direction of closing error. 2. Draw a straight line A'BCDEA to some suitable scale representing the ... plotted points and locate new position of station points to give correct traverse A'B'C'D'E'A'.

With neat sketch, explain the included angle method of plotting compass traverse.

Description : With neat sketch, explain the included angle method of plotting compass traverse. 

Last Answer : 1. Calculate all included angles of the traverse from observed bearings of the lines. e.g. <A, <B, <C, <D, <E  2. Check sum of included angles as equal to ( ... coincide with starting station (in case of closed traverse). If there is closing error, it needs to be corrected. 

Draw a neat sketch of optical square. Explain its working.

Description : Draw a neat sketch of optical square. Explain its working.

Last Answer : Optical Square: Working: The optical square consists of circular box 50 mm in diameter, 12.5 mm in depth. The box has three slits as A,B, and C. bb' is horizon glass, half silvered i.e ... the point on the chain line where the offset can be dropped to meet point J as shown in fig.  

Explain with neat sketch the procedure of reciprocal ranging.

Description : Explain with neat sketch the procedure of reciprocal ranging.

Last Answer : Reciprocal ranging / Indirect ranging Procedure: Let A and B be two survey stations. They are not mutually visible due to high ground between them. Let two assistant stands at M1 and N1 as ... and N1 which are nearer to line AB. Repeat same process until points M and N are established. 

Explain with neat sketch method of stepping of chaining on sloping ground.

Description : Explain with neat sketch method of stepping of chaining on sloping ground.

Last Answer : Procedure : To measure the horizontal distance between points A & B on sloping ground following steps should be followed ( Refer above figure.) 1. Starting from point A, the chain is unfolded and ... . Finally calculate total chained distance as d(AB) = d(AP1) + d(P2P3) + d(P4P5)

Explain intersection method of plane survey.

Description : Explain intersection method of plane survey.

Last Answer : Intersection method of plane tabling 1. Lay out a base line AB and measure it and Plot a distance ab' on sheet using any scale. 2.Set up instrument at A' with a' over A' 3.Orient the table by ... sighted rays bd, bg, bf, bc are drawn to determine points intersection, d, g, f, c.

What is meant by orientation? Explain orientation by back sighting method

Description : What is meant by orientation? Explain orientation by back sighting method

Last Answer : Orientation: The method of setting up the plane table at each of the successive stations parallel to the position it occupied at the starting station is known as orientation. Orientation by back sighting: ... ranging rod at A are perfect, then the orientation is said to be perfect.  

Explain the terms magnetic declination and dip of needle.

Description : Explain the terms magnetic declination and dip of needle.

Last Answer : Magnetic Declination: The horizontal angle between the magnetic meridian and true meridian is known as magnetic declination. When the north end of magnetic needle is pointed towards west side of ... needle is deflected downwards and southern hemisphere south end of the needle is deflected downwards.

What is meant by closing error? Explain graphical method of adjustment of closing error.

Description : What is meant by closing error? Explain graphical method of adjustment of closing error.

Last Answer : Closing error: The distance by which the traverse fails to close is called closing error. Step 1 ) Draw a horizontal line AA1 Equal to the length of perimeter of the traverse to a suitable scale 1) Mark ... 6) Join the the new points which gives the closed traversed. A, B, C,D and A.

Explain temporary adjustment of plane table survey.

Description : Explain temporary adjustment of plane table survey.

Last Answer : 1. Setting over the station: The plane table is fixed on tripod and adjust the table in such a way that table is approximately level. 2. Leveling the table: The tubular or spirit level is placed in two ... . The table can be oriented in two ways. i. Using trough compass. ii. By back sighting.

Explain principle of optical square with neat sketch.

Description : Explain principle of optical square with neat sketch.

Last Answer : Principle of optical square :- The angle between the first incident ray and the last reflected ray is twice the angle between the two mirrors In the case of optical square the angle between the mirrors is 45° while that between the first incident ray and last reflected ray is 90°.