State the procedure to find the foot of the perpendicular on the chain line to take the offset.

State the procedure to find the foot of the perpendicular on the chain line to take the offset. 
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1 Answer

Answer :

Ans: By cross staff

1. The cross staff is held vertically on the chain line where the offset is likely to occur. It is turned until one pair of opposite slits is directed to the ranging rod ( say B)

2. Though the other pair of slit point P is seen.

3. If it is not seen or bisected, cross staff is moved forward or backward on the chain line AB until the object P is seen.

4. Then P1 is the foot of perpendicular on the chain line.

5. Care should be taken to hold the staff vertically and is not twisted round at the time of bisection. 

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OR

By Indian optical square:

1. To take on offset to the object P the observer holds the instruments in his hand and stands on the chain line AB.

2. He turns the open face towards the object P, the forward station B is then sighted by looking through the opening which according to as the object P is to his right and walks along the chain line untill object appears exactly in line with the ranging rod at B.

3. The point P1 vertically under the instruments is required point. 

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Related questions

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Description : Describe the procedure of indirect ranging.

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Explain the procedure of profile leveling for construction of road.

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

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

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Description : A 20m chain was found to be 6cm too long after chaining a distance of 1059m. It was found to be 9cm too short after chaining at the end 1985m. If the chain was correct before commencement of work find the true distance.

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Draw a neat labeled sketch of 30m chain.

Description : Draw a neat labeled sketch of 30m chain.

Last Answer : neat labeled sketch of 30m chain

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A 20 m chain was found to be 10 cm too short after chaining 1000 m It was found to be 20 cm too short after chaining 1800 m. If the chain was correct before commencement of the work find the true distance.

Description : A 20 m chain was found to be 10 cm too short after chaining 1000 m It was found to be 20 cm too short after chaining 1800 m. If the chain was correct before commencement of the work find the true distance.  

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Define : 1) Bench mark 2) Datum surface 3) Line of collimation 4) Change Point

Description : Define : 1) Bench mark 2) Datum surface 3) Line of collimation 4) Change Point 

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Define horizontal line and vertical line.

Description : Define horizontal line and vertical line.

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Define: i) Level Line, ii) Horizontal Line, iii) Vertical Line iv) Bench Mark.

Description : Define: i) Level Line, ii) Horizontal Line, iii) Vertical Line iv) Bench Mark. 

Last Answer : j) Level Line: It is line lying in a level surface; it is therefore, normal to the plumb line at all points. ii) Horizontal Line: It is a straight line tangential to the level line at a ... RL determined with reference to the datum line. They serve as reference points for finding RL of new points. 

Define base line and check line with neat sketch.

Description : Define base line and check line with neat sketch. 

Last Answer : 1)Base Line : The longest line running roughly through the middle of the area to be surveyed is known as base line 2) Check line: The line joining the apex of a triangle to some fixed point on the ... A line joining some fixed point on any two sides of a triangle is known as check line. 

Define ‘ Fore bearing ’ & ‘ back bearing ’ of line with a neat sketch

Description : Define ‘ Fore bearing ’ & ‘ back bearing ’ of line with a neat sketch

Last Answer : Fore bearing : The bearing of line observed in the direction of progress of survey is called fore bearing of the line. Bearing of line AB is observed at A' towards B' is called as fore bearing of the line ... The bearing observed at B' towards A' is called as back bearing of the line AB'  

Define the term – base line and check line.

Description : Define the term – base line and check line.

Last Answer : Base line: Base line is generally the longest line running roughly through the middle of the area. It is laid on a level ground as far as possible. The whole frame work is built upon this line. ... point on the opposite side or a line joining some fixed point on any two sides of the triangle.

Define the term: (1) Level surface (2) Line of collimation

Description : Define the term: (1) Level surface (2) Line of collimation

Last Answer : Level surface: It is a surface parallel to the mean spheroidal surface of the earth. It is normal to the direction of plumb line at all points. The surface of still water is an example of level ... to the optical center of object glass and its continuation. It is also called as line of sight. 

Define the following terms: (i) Level surface {ii) Datum line (iii) Reduced level (iv) Axis of telescope

Description : Define the following terms: (i) Level surface {ii) Datum line (iii) Reduced level (iv) Axis of telescope

Last Answer : i)Level Surface : Any surface is parallel to mean spheroidal surface of earth is said to be a level surface. The water surface of still lake is also considered to be level surface. ii) ... an imaginary line passing through the optical Centre of object glass and optical Centre of the eye piece.

Describe in brief with neat sketch: i) Base line ii) Check line

Description : Describe in brief with neat sketch: i) Base line ii) Check line

Last Answer : i) Base line:  Base line is generally the longest line running roughly through the middle of the area. It is laid on a level ground as far as possible. The whole frame work is built upon this line. ... on the opposite side or a line joining some fixed point on any two sides of the triangle. 

Ranging in chain survey means (A) Looking at an isolated point not on the line (B) Establishing an intermediate point on the line (C) Determining the distance between end points (D) Determining the offset distance

Description : Ranging in chain survey means  (A) Looking at an isolated point not on the line  (B) Establishing an intermediate point on the line  (C) Determining the distance between end points  (D) Determining the offset distance 

Last Answer : (B) Establishing an intermediate point on the line

If the length of a transition curve to be introduced between a straight and a circular curve of radius 500 m is 90 m, the maximum perpendicular offset for the transition curve, is (A) 0.70 m (B) 1.70 m (C) 2.70 m (D) 3.70 m

Description : If the length of a transition curve to be introduced between a straight and a circular curve of  radius 500 m is 90 m, the maximum perpendicular offset for the transition curve, is  (A) 0.70 m  (B) 1.70 m  (C) 2.70 m  (D) 3.70 m

Last Answer : (C) 2.70 m 

Perpendicular offset from a tangent to the junction of a transition curve and circular curve is equal to (A) Shift (B) Twice the shift (C) Thrice the shift (D) Four times the shift

Description : Perpendicular offset from a tangent to the junction of a transition curve and circular curve is equal to (A) Shift (B) Twice the shift (C) Thrice the shift (D) Four times the shift

Last Answer : (D) Four times the shift

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Description : The perpendicular offset from the tan-get to the central point of the circular curve, is (A) (B) (C) R (1 - (D) R (1 -

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State the fundamental axes and mention their relationship for a dumpy level.

Description : State the fundamental axes and mention their relationship for a dumpy level.

Last Answer : Fundamental axis of dumpy level are as follows; i) The vertical axis ii) The axis of bubble tube iii) The line of collimation iv) The axis of the telescope Relationship between ... iii) Axis of telescope and line of collimation should coincide when dumpy level is correctly leveled.

State the situation where plane table is suitable.

Description : State the situation where plane table is suitable. 

Last Answer : 1) It is most suitable for preparing small scale maps 2) It is suitable in magnetic are where compass survey is not reliable 3) It is most suitable for filling in details between stations fixed by triangulation 4) It is suitable where accuracy is not required.

State the two uses of survey based on geodetic surveying

Description : State the two uses of survey based on geodetic surveying

Last Answer : Two uses of survey based on geodetic surveying:- i) To determine the precise position s on the surface of the earth. ii) Preparation of maps of large area like map of a country, state ... ) Establishment of GTS bench Marks across the country. iv) Preparation of military maps for defense purposes.

State the important points kept in mind while recording the staff readings in level pages with respect first reading, intermediate reading, last reading, change point, carry forward from one page to next page-Remark

Description : State the important points kept in mind while recording the staff readings in level pages with respect first reading, intermediate reading, last reading, change point, carry forward from one page to next page-Remark

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State the purposes of following methods of leveling. i)Profile leveling, ii)Fly leveling, iii)Check leveling iv)Reciprocal leveling

Description : State the purposes of following methods of leveling. i)Profile leveling, ii)Fly leveling, iii)Check leveling iv)Reciprocal leveling

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State fundamental lines and their relationships with each other of dumpy level.

Description : State fundamental lines and their relationships with each other of dumpy level.

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State advantages of plane table survey one each with respect to booking and suitability

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State two advantages of telescopic alidade over simple alidade.

Description : State two advantages of telescopic alidade over simple alidade.

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Define orientation. State two methods of orientation. Which method is most accurate and why?

Description : Define orientation. State two methods of orientation. Which method is most accurate and why? 

Last Answer : Orientation is the process of keeping plane table in same position as that is occupied in previous station. Methods of orientation: i) Magnetic meridian method using trough compass ii) Back ... and not by using trough compass. Therefore there is no error occurring due to local attraction.

State temporary adjustments of prismatic compass

Description : State temporary adjustments of prismatic compass

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State four instruments used for setting offsets.

Description : State four instruments used for setting offsets.

Last Answer : i) Instruments used for setting offsets: 1)Chain 2)Tape 3) Open & French Cross Staff 4) Circular & Indian Optical Square  ii) Principle of optical square: The angle between the first incident ray and the last reflected ray is twice to that of angle between two mirrors in optical square.