Explain the temporary adjustments of prismatic compass.

Explain the temporary adjustments of prismatic compass.
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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 is centered over a survey station correctly by means of a plumb bob or by dropping a pebble from the center of the instrument and moving tripod legs accordingly. 3. Levelling the compass The compass is quickly levelled by ball and socket arrangement by eye judgment. It should be levelled in such a way that dial moves freely and does not touch the rim of the compass. 4. Focusing the prism The triangular prism is moved using focusing stud so that readings on graduated ring will be seen clearly. 
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Related questions

State temporary adjustments of prismatic compass

Description : State temporary adjustments of prismatic compass

Last Answer : a) Setting the prismatic compass over prefixed survey station b) Centering the compass over nail point of station using plumb bob c) Leveling of compass in horizontal plane using level tube d) Focusing of prism by raising and lowering the focussing stud

Why zero is marked at south end on a graduated circle of prismatic compass?

Description : Why zero is marked at south end on a graduated circle of prismatic compass?

Last Answer : As bearing of any line is measured with respective north direction, while observing north direction, reading should be 00 0'. Therefore when object vane is bisecting north direction, at the same ... get bearings with respective north direction always, zero is marked at south end of magnetic needle.

Write the functions of the following components of prismatic compass i) Prism, ii) Lifting pin, iii) Prism cap, iv) Agate cap

Description : Write the functions of the following components of prismatic compass i) Prism, ii) Lifting pin, iii) Prism cap, iv) Agate cap

Last Answer : i) Prism: Reading printed on horizontal face of compass ring can be read from vertical position  ii) Lifting pin: When the instrument not in use the sight vane passes against the lifting pin which lift ... piece of hard glass provided on top of pivoted point, to reduce wear and tear of the point

State any eight component parts with its functions of prismatic compass.

Description : State any eight component parts with its functions of prismatic compass. 

Last Answer : Component parts of prismatic compass are as follows. 1. Break pin - It is used to stop the oscillations of aluminum ring. 2. Lifting pin - It lifts the magnetic needle when sight vane is folded. ... and sighting vane when the compass is not in use to protect the compass from dirt, dust etc.

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. 

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 labeled sketch of prismatic compass.

Description : Draw labeled sketch of prismatic compass.

Last Answer : Sketch of prismatic compass :

State the function of reflecting mirror in prismatic compass.

Description : State the function of reflecting mirror in prismatic compass. 

Last Answer : Function of reflecting mirror is to get image of an object located above or below the instrument level while bisection.

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 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'. 

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. 

State any four sources of errors in compass survey

Description : State any four sources of errors in compass survey 

Last Answer : Following are the sources of errors in compass survey1. Instrumental survey-  a. Needle may not be perfectly straight and might not be balanced properly over the station.  b. Graduations of the rings ... substances near the station.  b. Magnetic field may vary on account of some natural causes. 

State different methods of plotting compass traverse.

Description : State different methods of plotting compass traverse. 

Last Answer : Methods of plotting compass traverse are: 1. By parallel meridian through each station. 2. By included angle. 3. By paper protractor. 4. By rectangular co-ordinates. 5. Plotting by tangents. 6. Plotting by chords.

Enlist different errors in compass surveying.

Description : Enlist different errors in compass surveying.

Last Answer : Various errors in compass surveying are classified asi) Instrumental errors. ii) Personal errors or observational errors iii) Errors caused due to external errors (natural errors) i) ... magnetic declination. c) Local attraction due to proximity of magnetic substances or magnetic field.

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

State the functions of needle, glass cover, pivot and adjustable mirror of a compass.

Description : State the functions of needle, glass cover, pivot and adjustable mirror of a compass.

Last Answer : Needle: To direct north-south direction or to give magnetic meridian. Glass cover: To prevent entry of dust in box and movement of needle due to air or wind. Pivot: To support and balance the ... it is in use. Adjustable mirror: For sighting object at high or below level of observer's eye.

Describe in brief errors in compass survey.

Description : Describe in brief errors in compass survey.

Last Answer : Errors in Compass Surveying. The errors are classified as: 1. Instrumental errors. 2. Personal or Observational errors. 3. Errors due to External Influences (Natural errors etc.).  (1 ... in magnetic declination. (iii) Local attraction due to proximity of electric lines, steel structures etc.

State the principle of compass survey.

Description : State the principle of compass survey. 

Last Answer : The principle of compass survey is traversing, which involves a series of connected survey lines (may be open or closed) whose lengths and bearing are measured by linear and angular measuring instruments.

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 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.

The zero of the graduated circle of a prismatic compass is located at (A) North end (B) East end (C) South end (D) West end

Description : The zero of the graduated circle of a prismatic compass is located at  (A) North end  (B) East end  (C) South end  (D) West end 

Last Answer : (C) South end

Prismatic compass is considered more accurate than a surveyor's compass, because (A) It is provided with a better magnetic needle (B) It is provided with a sliding glass in the object vane (C) Its graduations are in whole circle bearings (D) It is provided with a prism to facilitate reading of its graduated circle

Description : Prismatic compass is considered more accurate than a surveyor's compass, because (A) It is provided with a better magnetic needle (B) It is provided with a sliding glass in the object vane ( ... whole circle bearings (D) It is provided with a prism to facilitate reading of its graduated circle

Last Answer : (D) It is provided with a prism to facilitate reading of its graduated circle

In chain surveying, perpendiculars to the chain line are set out by (A) A theodolite (B) A prismatic compass (C) A level (D) An optical square

Description : In chain surveying, perpendiculars to the chain line are set out by (A) A theodolite (B) A prismatic compass (C) A level (D) An optical square

Last Answer : (D) An optical square

In a perfect prismatic compass (A) Magnetic axis and geometric axis of the needle coincide (B) Ends of the needle and pivot are in same vertical and horizontal planes (C) Pivot is vertically over the centre of the graduated circle (D) All the above

Description : In a perfect prismatic compass (A) Magnetic axis and geometric axis of the needle coincide (B) Ends of the needle and pivot are in same vertical and horizontal planes (C) Pivot is vertically over the centre of the graduated circle (D) All the above

Last Answer : (D) All the above

Which one of the following statements is not correct ? (a) A surveyor’s compass has two sight vanes (b) A prismatic compass has an object vane and an eye vane (c) A trough compass is an accessory to a plane table (d) In a prismatic compass the graduations on the aluminimum disc rotate and the index remains stationary

Description : Which one of the following statements is not correct ? (a) A surveyor's compass has two sight vanes (b) A prismatic compass has an object vane and an eye vane (c) A trough compass ... table (d) In a prismatic compass the graduations on the aluminimum disc rotate and the index remains stationary

Last Answer : (a) A surveyor’s compass has two sight vanes

The survey instrument used for reconnaissance survey (a) Theodelite & Dumpty level (b) Prismatic compass & Aneriod barometer* (c) All the above (d) None of them

Description : The survey instrument used for reconnaissance survey (a) Theodelite & Dumpty level (b) Prismatic compass & Aneriod barometer* (c) All the above (d) None of them

Last Answer : (b) Prismatic compass & Aneriod barometer*

Which of the instruments is not used in Reconnaissance survey. (a) Prismatic compass (b) Dumpy level * (c) Aneroid Barometer (d) Pedometer

Description : Which of the instruments is not used in Reconnaissance survey. (a) Prismatic compass (b) Dumpy level * (c) Aneroid Barometer (d) Pedometer

Last Answer : (b) Dumpy level *

List any eight component parts of prismatic compass with their function in brief.

Description : List any eight component parts of prismatic compass with their function in brief.

Last Answer : Component parts of compass with their function. Sr.No Component Function 1 Circular metal box  To protect needle and pivot. 2 Steel pivot To carry magnetic ... prism to eye sight of observer 14 Magnetic needle To obtain the north direction. 

Which one of the following statements is not correc t? (a) Parallax error is eliminated when there is no change in the staff reading when eye is moved up and down (b) The objective lens is to be focused towards a white or bright background for clear visibility of cross-hairs (c) Temporary adjustments of the dumpy level are to be performed at every set up (d) The eyepiece need not be adjusted after the first set up when the same surveyor is taking readings

Description : Which one of the following statements is not correc t? (a) Parallax error is eliminated when there is no change in the staff reading when eye is moved up and down (b) The objective lens is ... (d) The eyepiece need not be adjusted after the first set up when the same surveyor is taking readings

Last Answer : (b) The objective lens is to be focused towards a white or bright background for clear visibility of cross-hairs

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 .  

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.

Last 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

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.

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

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 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 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 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 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 ‘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'

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 Graphical adjustment of closing error in a closed traverse.

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

Last Answer : Step: 1) Draw a horizontal line AA1 equal to the length of perimeter of the traverse to a suitable scale. 2) Mark the distances AB,BC,CD, etc on the line as per their lengths. 3) Draw a perpendicular ... errors 7) Join the the new points which gives the closed traversed. A, B, C, D and A.

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.