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

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

Offsets are lateral measurement to the base line. They are Located by judgment if short And by instruments (optical square or cross staff) if long and measured by metallic tape and shown with their chainages on base line

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Related questions

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.

State and describe the types of offsets.

Description : State and describe the types of offsets. 

Last Answer : 1. Perpendicular offset- When the offset is taken at 900 to the survey line, then it is known as perpendicular offset. 2. Oblique offset- When the offset is taken at an angle other than 900 ( ... when offset is set by swinging chain or tape to survey line, such formed offset is called Swing offset.

State any four types of offsets and define them.

Description : State any four types of offsets and define them. 

Last Answer : i) Long offset: If length of offset more than 15 m. ii) Short offset: If length of offset less than 15 m. iii) Perpendicular offset: Offset taken perpendicular to chain line. iv) Oblique offset: Offset not taken perpendicular to chain line.

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

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

Last Answer : Principal of optical square :- the angle between the first incident ray and the last reflected ray is twice the angle between the two mirrors OR If there are two plane mirrors whose reflecting surfaces ... is 450 while that between the first incident ray and last reflected ray is 900 .  

Draw a sketch and explain how to find height of chajja or slab using dumpy level.

Description : Draw a sketch and explain how to find height of chajja or slab using dumpy level.

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.

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

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

Last Answer : Procedure: 1.Set plane table over station A use plumbing fork for transferring station point from ground on sheet. Draw the direction of magnetic meridian with the help of compass. 2. With the ... scale Similarly, the table can be set at other successive station and traverse is completed.

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

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

Last Answer : Working of optical square1. Optical square works on principle of optical square to set perpendicular offset 2. Keep ranging rods at point B and C as shown in fig. 3. Observe the ... matched each other point D can be marked on ground and distance CD is measured as perpendicular offset.

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

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

Last Answer : This method is used when all the points to be plotted are visible from single instrument station. Steps are: 1. Select a suitable point P on the ground such that all the details are visible from it. 2. Center and ... , pc, pd, pe respectively. Join a, b, c, d, and e to give the outline.

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 the procedure for profile leveling with neat sketch.

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

Last Answer : 1) Let PQR be the given line of section.   2) Mark point at 10 m intervals on this line. 3) Level is set up on a firm ground at a suitable point I1. 4) Temporary adjustment of level is done and B. ... and set up on firm ground at I2 as before. 10) B.S is taken on CP1 and new HI is calculated  

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 Fly Levelling with neat sketch. State situation under which fly levelling is needed.

Description : Explain Fly Levelling with neat sketch. State situation under which fly levelling is needed.

Last Answer : Ans: When DifferentialLevelling is done in order to connect a bench mark to the starting point of the alignment of any project, it is called as fly levelling. Fly levelling is also done to connect ...  ii)if distance is more between two points.  iii)if there obstacles between the two points.  

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 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 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°.  

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

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

Last Answer : The procedure to measure horizontal distance between the points A and B on sloping ground is as follows. 1. Two persons-leader and follower are required for chaining. 2. The follower holds the end of chain at A. The leader goes ... between A and b L = AM, + MN' + NO' + OP' + PQ' + QB'

Explain reciprocal levelling with neat sketch.

Description : Explain reciprocal levelling with neat sketch. 

Last Answer : Reciprocal levelling is adopted i) To find the difference in level accurately Between the two points considerably apart. ii) When it is not possible to set up the level in between the two points ... true difference is equal to the mean of the two apparent differences of level between A and B 

Draw sketch and write the procedure for setting offset to the left or right side of suvey line with open cross-staff.

Description : Draw sketch and write the procedure for setting offset to the left or right side of suvey line with open cross-staff.

Last Answer : Procedure for setting offset with open cross staff : 1. Keep the ranging rods at point P(fixed on survey line) and at point A1 approximately. 2. The cross staff with stadia rod is fixed ... can be fixed and perpendicular offset AB is said to be set to given survey line PQ in left side.

Draw a neat sketch of an arrow with dimensions.

Description : Draw a neat sketch of an arrow with dimensions.

Last Answer :  neat sketch of an arrow with dimensions

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

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'  

With neat sketch, write the procedure of measurement of fore bearing with compass.

Description : With neat sketch, write the procedure of measurement of fore bearing with compass.

Last Answer : For measuring fore bearing of line AB, i) Place the compass over station A, center and level it.  ii) Looking through eye slit towards object vane, bisect the ranging rod at station ... which coincides with horse hair at observer end. The observed reading is the fore bearing of line AB

Draw a neat sketch of prismatic compass and label its component parts

Description : Draw a neat sketch of prismatic compass and label its component parts

Last Answer : Sketch of prismatic compass and label its component parts

Draw the sketch of chain triangulation and label different lines.

Description : Draw the sketch of chain triangulation and label different lines.

Last Answer : AB – Base line AC, CD, DE, AE, EB - main survey lines DD’ – Check line. ab – Tie line.

Differentiate between simple levelling and differential levelling with neat sketch.

Description : Differentiate between simple levelling and differential levelling with neat sketch. 

Last Answer : S.N Simple Levelling Differential levelling 1 Instrument is not shifted till the end of survey work.  Instrument is shifted as per requirements. 2 In this difference in elevation between ... elevation between two points is more or any obstacle between them. 4

Draw labeled sketch of prismatic compass.

Description : Draw labeled sketch of prismatic compass.

Last Answer : Sketch of prismatic compass :

Draw sketch of optical square and state its principle.

Description : Draw sketch of optical square and state its principle.

Last Answer : The optical square is an instrument used to set perpendicular offset on the chain line. The optical square works on the principle of optics. Principle of optical square: The angle between the incident ray and reflected ray is twice the angle between mirrors.

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. 

State the meaning of local attraction and state its effect on prismatic compass and how it taken care of.

Description : State the meaning of local attraction and state its effect on prismatic compass and how it taken care of. 

Last Answer : Local attraction: It is the deviation or deflection of magnetic needle from its normal position under influence of external magnetic forces is called as local attraction.  Effect on prismatic compass: ... compass. 3) If local attraction still persists, it is corrected by mathematical calculation. 

State any four precautions to be taken while selecting stations for chain surveying.

Description : State any four precautions to be taken while selecting stations for chain surveying.

Last Answer : Following are the precautions to be taken while selecting station for chain surveying. 1) As far as possible the survey work should be based upon the basic principle of surveying i.e. working from whole to ... level ground. 9) The survey lines should run as far as possible nearer to object.

Enlist the sources of error in chaining and state the precautions to be taken against error.

Description : Enlist the sources of error in chaining and state the precautions to be taken against error.

Last Answer : In general, the distance measurement obtained in the field will be in error. Errors in the distance measurement can arise from a number of sources: 1. Instrument errors: A chain may be faulty due to a defect ... confuse 10 m tag with 20 m tag. It should be avoided by noticing the 15 m tag.

Explain the temporary adjustments of prismatic compass.

Description : Explain the temporary adjustments of prismatic compass.

Last Answer : Temporary Adjustments of Prismatic Compass 1. Fixing the compass to the tripod The compass is fixed on a tripod by rotating screw head of tripod stand. 2. Centering the compass The prismatic compass ... prism is moved using focusing stud so that readings on graduated ring will be seen clearly. 

Explain temporary adjustment.

Description : Explain temporary adjustment.

Last Answer : 1) Place the telescope parallel to foot screw (fig. a) 2) Bring the bubble at Centre by moving foot screw inward or outward simultaneously. 3) Then turn the telescope through 900 so that it ... 6) Once both positions give centered bubble, leveling of instrument is said to be completed.

Explain in brief linear measurement using : i) Pacing ii) Digital Tape

Description : Explain in brief linear measurement using : i) Pacing ii) Digital Tape 

Last Answer : i) Pacing : This method is used only for knowing approximate distance between the objects. In preliminary survey this method can be used for linear measurement. This method consists of counting the ... and compact and measures accurate reading. The maximum measuring length of digital tape is 4.8m 

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

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

Last 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 ... Karachi are given in catalogue formed by department. They are also known as G.T.S. Bench mark

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

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

Last Answer : A) river across the chain line. 1. Suppose AB is the chain line. Two points C & D are selected on this line on opposite banks of the river. 2. At C a perpendicular CE is erected and bisected at F. A perpendicular is ... ) X DF          CH=DF  = (CD/(CG-DF) )X DF        HG=CG-CH

Explain types of bench marks.

Description : Explain types of bench marks.

Last Answer : Types of bench mark 1.Great trignometrical survey bench marka. These are the bench marks established with very high precision at regular intervals by survey of India Dept. all over the country . Their ... point. Such point should be on a permanent object so that next day it is easily identified.

Explain in detail classification of survey.

Description : Explain in detail classification of survey. 

Last Answer : A. primary classification-  1. Plane surveying: In this survey curvature of the earth is not taken in to consideration.  2. Geodetic surveying: In this survey curvature of the earth is taken ... 3. Based on nature of field:  1.Land surveying  2.Marine surveying  3.Astronomical surveying

State different types of leveling. Explain any one in brief.

Description : State different types of leveling. Explain any one in brief.

Last Answer : Types of Levelling  1. Simple Levelling.  2. Differential Levelling.  3. Fly Levelling.  4. Longitudinal or profile leveling.  5. Cross-Section Levelling.  6. Check Levelling.  1. ... B are taken. The difference of these readings gives the difference of level between A and B. 

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

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

Last Answer : i) The board not being horizontal- This error affects chiefly the measurement of vertical angles. ii) The table not being accurately centered. The plotted position of the occupied station not ... and correct any displacement. v) The defective sighting- The object not being correctly sighted.

Explain four types of meridians.

Description : Explain four types of meridians. 

Last Answer : 1. True meridian: -The line which is passing through geographical north or south pole and given point on the surface of earth is called as true meridian. 2. Magnetic meridian:-The direction indicated ... particular zone. These lines are termed as grid lines and the centre line as the grid meridian.

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 ‘Declination of Magnetic needle’ and types of declination.

Description : Explain ‘Declination of Magnetic needle’ and types of declination. 

Last Answer : Ans: The magnetic meridian at a place does not coincide with the true meridian at that place. The horizontal angle made by the magnetic meridian with the true meridian is called magnetic declination'. ... in others it points to the west of the true meridian called as West declination'