Explain principle of chain surveying 

1 Answer

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 figure which can be plotted by measuring its sides alone in the field. 4) No angular measurements are taken. 5) To obtain good result, the framework should consists of triangles which are nearly equilateral. Such triangles are known as well shaped or well conditioned triangles. 6) Well conditioned triangles can be plotted more accurately than the ill conditioned triangles. 7) Ill conditioned triangles should always be avoided. 8) The frame work of triangles to be adopted depends upon the shape & configuration of the ground & the natural obstacles. 

Related questions

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.

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.

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.

Description : The process of surveying is therefore in three stages namely:

Last Answer : (i) Taking a general view This part of the definition is important as it indicates the need to obtain an overall picture of what is required before any type of survey work is undertaken. In ... of quantities, datasheets, drawings and in land surveying maps and plan showing the features on the land.

Description : Tacheometric Surveying

Last Answer : Tacheometric is a branch of surveying in which horizontal and vertical distances are determined by taking angular observation with an instrument known as a tachometer. Tacheometric surveying is adopted in rough ... be prepared for investigation works within a short time on the basis of such survey.

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.

Description : Describe back sighting method of orientation of plane table surveying.

Last Answer : Backsight method of orientation 1. Assume we have to orient the table at next station B' represented on paper by point b'. 2.the line ba' is drawn on previous station A'. 3.the alidade is kept ... A'. 4. When the plotted line ab' coincides with line AB' and table will be oriented.

Description : Define surveying.

Last Answer : Surveying- It is branch of civil engineering in which relative positions of ground points are determined by taking linear and angular measurement.

Description : Define surveying & state its objectives

Last Answer : Surveying- It is branch of civil engineering in which relative positions of ground points are determined by taking linear and angular measurement. Objectives: 1. To determine the relative positions of ... quantities 4. To prepare a topographical map showing details of hills, valleys and rivers.

Description : State any four classification of surveying based on instrument uesd. 

Last Answer : i) Chain survey ii) Plane table survey iii) Theodolite survey, iv) Tachometric survey v) compass survey vi) photographic survey, vii) Aerial survey 

Description : State any two uses of Plane Surveying. 

Last Answer : 1) Plane surveying is used for measuring small distance. 2) When area is less than 260 km2, plane survey is normally done. 3) When desired accuracy is less, plane survey is done.

Description : State the use of alidade in plane table surveying

Last Answer : 1) It is used for sighting the objects to be located.  2) It is used for drawing the rays. 

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.

Description : Write-four uses of surveying.

Last Answer : Uses of surveying are: 1) Surveying is useful to plot ground details in various maps like topographic and cadastral maps. 2) It is useful in navigational movement planning through military survey. ... beneficial in collecting details of water bodies on earth like lake, pond, river, sea etc.

Description : State the limitations of plane table surveying.

Last Answer : 1) It is not suitable for work in wet climate 2) Several accessories are required to be carried hence possibility lost. 3) Replotting of survey work to different scale is difficult in absence of ... ) It is not intended for accurate work. 6) The plane table is essentially a tropical instrument.

Description : Describe in brief resection method of plane table surveying.

Last Answer : This method is used for establishing the instrument stations only. After fixing the stations, details are located either by radiation or intersection. The characteristic feature of resection is that the point ... of resection are (1)The Two Point Problem, and (2)Three Point Problem.

Description : Describe in brief primary classification of surveying

Last Answer : Primary Classification Geodetic Survey The geodetic surveying is that type of surveying which takes into account the curvature of earth's surface. It is generally adopted for large area (more than ... large scale such as Bridges, Dams, Location and Construction of canals, highways, railways etc.

Description : State the principles of surveying. 

Last Answer : Main principles of surveying are: 1) To work from whole to part. 2) To locate a point at least by two independent processes

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'. 

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 .  

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°.  

Description : What consideration would you have while selecting survey stations and survey lines in a chain survey?

Last Answer : Following points to be considered while selecting survey stations and survey lines 1) Main survey station should be mutually visible. 2) All triangles should be well conditioned. 3) The survey line should lie ... of the area so as to form the frame work of triangles on it to cover maximum area. 

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.

Last Answer : Given : Line ABC, AB=1059m, AC=1985m  L= 20m, No error at start, 0.06m too long at B,  0.09m too short  Find : True distance of AC = ? Solution : For part AB L = Length of chain= 20 m e = Average ... Total true distance of AC = True distance of (AB + BC)  = 1060.59 m + 922.52 m  = 1983.11 m

Description : Describe method of measuring distances on ground using chain and arrows.

Last Answer : Method of measuring distances on ground. 1. Mark the position of survey stations whose distance is to be measured using wooden peg. (say A and B) 2. now, ranging is done if distance ... station B. Thus total horizontal distance will be equal to addition of distances measured of each parts.

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

Last Answer : neat labeled sketch of 30m chain

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

Last 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 ... the ranging rod at B. 3. The point P1 vertically under the instruments is required point. 

Description : State the uses of following instruments in survey: i)Cross staff ii) Chain iii) Pegs iv) Arrows

Last Answer : i) Cross-Staff: To set up perpendicular or right angle to given chain line OR to find foot of perpendicular from given object to a chain line. ii) Chain: Chains are used for measuring distances. iii) ... on survey lines. iv) Arrows : They are used to mark the end of each chain during chaining. 

Description : State the situations under which chain survey is most suitable

Last Answer : Situations under which chain survey is most suitable 1) It is suitable for moderately small areas 2) When the ground is fairly level with simple details ( free from obstructions such as trees, building, poles etc ) 

Description : The length of line measured by 20 m chain was found to be 751 m. The chain was tested before start of measurement and was found correct. The chain was again tested after measurement and was found 6 cm too short. What shall be the correct length of line ?

Last Answer : Given Data: Standard length of chain (L)= 20m Measured Length (M.L.) = 751 m Error before start of measurement = 0.0 Error after measurement = 6 cm = 0.06 m To Find: Actual length or Correct length Solution: ... (L'/L)  = (751) x (19.97/20)  = 749.87 Correct length of line is 749.87 m

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.

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.  

Last Answer : Average error in chain for 1000 m length = (0 + 10) / 2 = 5 cm = 0.05 m too short True length up to 1000 m = (20 - 0.05) x 1000 / 20 = 997.5 m. Average error in chain from 1000 m to 1800 m length = (10 ... 1800 m length = (20 - 0.15) x 800 / 20 = 794.0 m. True distance = 997.5 + 794 = 1791.5 m.

Description : Draw a "well labelled diagram of 30 m metric chain & state the function of swivel joint & oval rings.

Last Answer : Swivel joint: To turn the handle without twisting the chain. Oval ring: To provide flexibility and fold the chain.

Description : Enlist the factors affecting on selection of survey station or survey line in chain survey.

Last Answer : Following are the factors affecting on selection of survey 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 ... level ground. 9) The survey lines should run as far as possible nearer to object.

Description : The length of line measured with a chain was found to be 250m. Calculate the true length of line if i) The length was measured with 30 m chain and the chain was 10cm too long and ii) The length of chain was 30 m in the beginning and 30.10 m at the end of the work. 

Last Answer : Given Data: L = 30 m Measured Length = 250 m Solution: Case i) The length was measured with 30 m chain and the chain was 10cm too long L' = 30 + 0.1 = 30.1 m Correct Distance = (L'/L) x Measured Length ... = 30.05 m Correct Distance = (L'/L) x Measured Length  = (30.05/30) x 250  = 250.42 m

Description : Define orientation and principle of plane tabling. 

Last Answer : Orientation: The orientation of plane table means keeping the plane table at all stations parallel to the position it occupied at first station. Principles of plane table survey: 1. The rays drawn from ... same as that of previous station i.e. orientation should be done at each changed station.  

Description : State the principle of plane table survey. 

Last Answer : Principle of plane table survey 1. The rays drawn from different points should pass through a single point i.e. position of station point.  2. The position of table should be same as that of previous station i.e. orientation should be done at each changed station.

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.

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.

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. 

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

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.

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.

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 

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

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.

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

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.

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

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. 

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.