ONE MORE STEP TOWARD BETTER TOMORROW : November 2025

Thursday, 20 November 2025

study of total station

study of theodolite survey and ranging by theodolite

study of dumpy level and setting up of dumpy level in field

plane table surveying and different method of plane table survey

Study of compass survey , plotting an area and various type of compass used in survey

COMPASS SURVEY

1.Chain surveying can be used when the are to be

surveyed is comparatively smaller and is fairly flat.

2.But when the area is large in such cases chain

surveying is not possible

3.In Traversing the frame work consists of number of

connected lines

4.The lengths are measured by using tape or chain

and angles are measured by using compass

Type of traverses

1) Open traverse

2) Closed traverse

Principle of compass surveying involves a series of connected lines the magnetic

bearing of the lines are measured by prismatic compass and distance are measured by

using chain surveying

Compass surveying is not recommended for areas where local attraction is suspected

due to local attraction like steel structures, magnetic e..t..c .

Types of compass

1. Prismatic compass surveyor

2.Surveyor compass

Prismatic compass

Prismatic compass is a magnetic compass which consist of following parts

Cylindrical metal box having diameter 8-12cm.

It is protected from dust and rains e .t. c

Pivot

Pivot is provided at the centre of compass and support freely suspended magnetic needle

over it .

Lifting pin and lever arm

lifting arm is provided just below the sight vane

When the sight vane is folded it press the lifting pin

Magnetic needle

Magnetic needle is the heart of the instrument

This needle measures angle of a line from magnetic meridian a the needle always pointed the

north and south at the two ends of the needle when freely suspended on any support

Graduated circle

This is a aluminum graduated ring marked from 0 to 360 to measure all the possible angles of

a line

Prism

Prism is used to read graduations on a ring and to take exact reading by compass

Object vane

Object vane is diametrically opposite to the prism and eye vane the object vane carries a horse

vane to sight the object by eye vane

Eye vane

Eye vane a fine slit is provided with eye hole at the bottom to bisect the object from the slight

and to take reading simultaneously from the eye hole

Glass cover

It covers the instrument from dust and wind e. t. c

Working of prismatic compass
when the needle of compass suspended freeely .its always points towards north ,there fore all
the angles measured now are said to north oriented (magnetic meridian)
The horizontal angle made by a survey line with reference to magnetic meridian in clockwise
direction is called bearing of the line
Temporary adjustments of compass
Centering
Leveling
Focusing
Centering : it is the process of placing the compass exactly over the station where the
bearing is to be determine .
The centering is checked by dropping a small pebble or plum bob
Leveling :leveling of the compass is done aim to free swimming the graduated circular
ring of the prismatic compass
If not ball and socket is should be adjusted
Focusing:
Prism is move up and down in its slide till the graduations of the aluminum ring are clear and
sharp

surveying assignment

Multiple Choice Questions and Answers :-

1. A metallic tape is made of

a) steel

b) invar

c) linen

d) cloth and wires

Ans: d

2. For a well-conditioned triangle, no angle should be

less than

a) 20°

b) 30°

c) 45°

d) 60°

Ans: b

3. The angle of intersection of the two plane mirrors of

an optical square is

a) 30°

b) 45°

c) 60°

d) 90°

Ans: b

4. The allowable length of an offset depends upon the

a) degree of accuracy required

b) method of setting out the perpendiculars and nature of

ground

c) scale of plotting

d) all of the above

Ans: d

5. The permissible error in chaining for measurewith chain on rough or hilly ground is

a) 1 in 100

b) 1 in 250

c) 1 in 500

d) 1 in 1000

Ans: b

6. The correction for sag is

a) always additive

b) always subtractive

c) always zero

d) sometimes additive and sometimes subtractive

Ans: b

7. Cross staff is an instrument used for

a) measuring approximate horizontal angles

b) setting out right angles

c) measuring bearings of the lines

d) none of the above

Ans: b

8. Contour interval is

a) the vertical distance between two con-secutive contours

b) the horizontal distance between two consecutive contours

c) the vertical distance between two points on same contour

d) the horizontal distance between two points on same contour

Ans: a

9. Benchmark is established by

a) hypsometry

b) barometric levelling

c) spirit levelling

d) trigonometrical levelling

Ans: c

10. The type of surveying which requires least office work is

a) tacheomefry

b) trigonometrical levelling

c) plane table surveying

d) theodolite surveying

Ans: c

11. Intersection method of detailed plotting is most suitable for

a) forests

b) urban areas

c) hilly areas

d) plains

Ans: c

12. Three point problem can be solved by

a) Tracing paper method

b) Bessels method

c) Lehman’s method

d) all of the above

Ans: d

13. The size of a plane table is

a) 750 mm x 900 mm

b) 600 mm x 750 mm

c) 450 mm x 600 mm

d) 300 mm x 450 mm

Ans: b

14. The process of determining the locations of the instrument

station by drawing re sectors from the locations of the known

stations is called

a) radiation

b) intersection

c) resection

d) traversing

Ans: c

15. The instrument used for accurate centering in plane table

survey is

a) spirit level

b) alidade

c) plumbing fork

d) trough compass

Ans: c

16. After fixing the plane table to the tripod, the main

operations which are needed at each plane table station are

i) levelling

ii) orientation

iii) centering

The correct sequence of these operations is

a) (i), (ii),.(iii)

b) (i), (iii), (ii)

c) (iii), (i), (ii)

d) (ii), (Hi), (i)

Ans: b

17. Bowditch rule is applied to

a) an open traverse for graphical adjustment

b) a closed traverse for adjustment of closing error

c) determine the effect of local attraction

d) none of the above

Ans: b

18. If in a closed traverse, the sum of the north latitudes is more

than the sum of the south latitudes and also the sum of west

departures is more than the sum of the east departures, the

bearing of the closing line is in the

a) NE quadrant

b) SE quadrant

c) NW quadrant

d) SW quadrant

Ans: b

short answer questions

1. Describe the principle of surveying.

The fundamental principles upon which the surveying is being carried out are

Working from whole to part.

After deciding the position of any point, its reference must be kept from at least two permanent objects or stations whose positions have already been well defined.

2. What do you mean by reciprocal ranging?

When the end stations are not intervisible due to high ground or a hill or if the ends are too long. In such cases, intermediate points can be fixed on the survey line by a process known as Reciprocal ranging or Indirect ranging.

3. What do you mean by scale in surveying?

Scale is a fixed ratio that every distance on the plan bears with corresponding distance on the ground. For example: 1cm = 10m

4. Define and distinguish between plane and geodetic surveying.

5. Name the different methods adopted in scale of a plan/map.

Plain Scale

Diagonal Scale

Vernier Scale

Scale of chords

6. What are arrows?

Arrows are also called marking or chaining pins, and are used to mark the end of each chain

during the process of chaining.

7 What is plumb Bob?

Plumb Bob is used to locate points directly below or above another point. It is also used for

accurately centering of compass or level or theodolite over a station mark, and for testing the

verticality of ranging poles.

8 Define surveying.

Surveying is defined as the science of making measurements of the earth specifically the

surface of the earth.

9 What are the works of a surveyor in office?

In office work, converting field measurements (also called reducing) involves the process of

computing, adjusting, and applying a standard rule to numerical values.

10 What are the types of corrections to be applied?

Correction for Length.

Correction for Temperature.

Correction for Pull.

Correction for Sag.

Correction for Slope.

direct and indirect ranging during chain surveying

Ranging : In measuring the length of a survey line, it is necessary

that the chain should be laid on the ground in a straight line between the end

stations. If the line is short, it is easy to put the chain in true alignment. But if the

line is long, it is necessary to place intermediate ranging rods to maintain the

direction. Fixing of intermediate points in a straight line between the two end

stations is known as ranging.

Ranging is of two types: a) Direct ranging b) Indirect ranging.

(a) Direct Ranging

Direct ranging is adopted when the two end stations are mutually visible.

The ranging is carried out by an eye or a line ranger.

Ranging by Eye

The ranging by eye is done by the following steps.

1) Fix ranging rods at each end of the line.

2) Stand about 1.5m beyond the first ranging rod.

3) Direct the assistant to hold the ranging rod vertically where the intermediate

point to be fixed.

4) Direct the assistant to move left or right using code of signals until the

three ranging rods are in straight line.

5) Check the verticality of the rods by sighting the lower ends of the rods.

6) As and when the intermediate point is in straight line, signal the assistant

to fix the ranging rod.

The following code of signals may be used in directing the assistant into

line.

Rapid sweep with right hand – move rapidly to the right.

Rapid sweep with left hand – move rapidly to the left.

Slow sweep with right hand – move slowly to the right.

Slow sweep with left hand – move slowly to the left.

Right arm extended – move continuously to right.

Left arm extended – move continuously to left.

Right arm up and moved to the right – plumb the rod to the right.

left arm up and moved to the left – plumb the rod to the left.

Both hands up and brought down – correct.

Both arms extended forward

horizontally and the hands depressed – fix the ranging rod in position.

briskly.

Ranging by Line Ranger

Line ranger is an optical instrument used for fixing intermediate points on a

chain line. It consists of two right angled isosceles triangular prisms placed one

above the other.

For fixing an intermediate station P on the line AB, the observer stands as

near P as possible and holds the instrument at his eye level. Rays of light coming

from the ranging rods at A and B are reflected by the upper and lower prisms

respectively and reach the eye. If the images of A and B are in separate lines as

shown in fig (b), the observer moves a little perpendicular to AB such that both

images will be in the same line as in fig(c).

The required position of P will be then exactly below the center of the

instrument. One of two prisms can be adjusted by a screw. To test the instrument

it is held at the mid point of a line and the ranging rods at the end station observed.

If both rods appear in the same line, the instrument is in adjustment. Otherwise,

the fixing screw of the movable prism is slackened and the prism slightly rotated

so that both ranging rods appear in one line. Then the prism is fixed by tightening

the fixing screw.

Indirect Ranging

Indirect ranging is adopted when the ends of the line are not mutually visible

due to high intervening ground or the distance is too long. The process is also

known as reciprocal ranging.

Let A and B are the ends of a chain line which has a rising ground intervening between them. Two chainmen with ranging rods take the position M such that they are as nearly is line with A and B as they could judge and such that the chainman at M1 could see N1 and B and chainman at N1 can see M and A. First chainmen at N1 direct M1 to M2 so that he comes in line with A and N1 Then the chainman at M2directs N1 to N2 such that he comes in line with B and M1

This process is repeated so that they align each other successively directing each other until they are in the line AB.

study on various type of chain used in chain survey and its component and study of error in surveying

principle of chain surveying: Chain surveying is the type of surveying in

which only linear measurements are made in the field. The main principle of

chain surveying or chain triangulation is to provide a framework consist of

number of well-conditioned triangles or nearly equilateral triangles. It is used

to find the area of the field.

Suitability of Chain Survey

Chain survey is suitable in the following cases

1. Area to be surveyed is comparatively small

2. Ground is fairly level

3. Area is open and

4. Details to be filled up are simple and less.

5. Survey Station

6. Survey stations are of two kinds

7. Main Stations

8. Subsidiary or tie

Main Stations

Main stations are the end of the lines, which command the boundaries of the

survey, and the lines joining the main stations re called the main survey line or

the chain lines.

Subsidiary or the tie stations are the point selected on the main survey lines,

where it is necessary to locate the interior detail such as fences, hedges,

building etc.

Tie or subsidiary lines

A tie line joints two fixed points on the main survey lines. It helps to checking

the accuracy of surveying and to locate the interior details. The position of each

tie line should be close to some features, such as paths, building etc.

Base Lines

It is main and longest line, which passes approximately through the center of

the field. All the other measurements to show the details of the work are taken

with respect of this line.

Check Line

A check line also termed as a proof line is a line joining the apex of a triangle to

some fixed points on any two sides of a triangle. A check line is measured to

check the accuracy of the framework. The length of a check line, as measured

on the ground should agree with its length on the plan.

Well - conditioned triangle: A well conditioned triangle is a triangle in which

no angle is less than 30 degrees. One of the way to survey the area is to divide

the entire area is smaller triangles and then take the measurement of sides of

the triangles.

A well conditioned triangle will have its edges far enough and vertex will be

clearly identified. Ill-conditioned triangle can have ambiguity in vertex position

and so, it can lead to wrong measurements. Compare two triangles below:

ERRORS IN CHAINING:

Errors in chaining may be classified as:

1. Personal errors

2. Compensating errors, and

3. Cumulative errors

Personal errors: Personal errors like wrong reading, wrong recordings, reading

from wrong end or chain and miscounting of the chains are serious errors. It is

not easy to detect unless they are too big. Hence, care should be taken to avoid

such errors.

Compensating errors: These errors can be positive or negative. Hence, they

are likely to get compensated when a large number of readings are taken. The

following are the examples of such errors: 1) Incorrect marking of the end of

chain

2) Fractional parts of the chain may not be correct when the chain is corrected

by adding or removing a ring.

3) Graduation in the tape may not be exactly of same length throughout

4) In the method of stepping for measuring sloping ground, method of

plumbing may be crude.

Cumulative errors: These are the errors which occur always in the same

direction. Hence, as more number of chain lengths is required while measuring

a line they go on accumulating. Hence, even if each one of such errors are

small they are considerable when longer lengths are measured.

Examples of such errors are: 1. Bad ranging ( +ve)

2. Bad straightening

3. Non – horizontality

4. Sag in the chain

5. Erroneous length of chain

6. Temperature variation

7. Variation in pull.

First four errors are always + ve since they make measured length more than

actual. Last three errors may be +ve or –ve.

Wednesday, 19 November 2025

study of linear measurements using different instruments and use of field book

Surveying is the science and art of determining the relative positions of the points on, above (or) beneath the earth surface.

Primary divisions of surveying: Surveying may primarily be divided into two divisions

1. Plane surveying

2. Geodetic surveying

Plane surveying: The surveys in which earth surface is assumed as plane and the curvature of the earth is ignored, are known as Plane surveys.

Geodetic surveying: The surveys in which curvature of the- earth is taken into account and higher degree of accuracy in linear and angular observations, is achieved, are known as Geodetic surveys.

Liner measurements and equipment's:

In engineering survey, the linear horizontal distance is to be measured to complete a survey. The measurement of this linear horizontal distance between two points on the earth surface is known as linear measurement. Linear measurement can be achieved by various instruments.

The following instruments are used while chaining:

1. Chains

2. Tapes

3. Arrows

4. Ranging rods and offset rods

5. Pegs

6. Plumb-bob

Chain

The chain is composed of 100 or 150 pieces of galvanized mild steel wire called links, joined together with oval rings and handles at both ends. The end of each link are bent into a loop and connected together by means of three oval rings. The ends of the chain are provided with brass handles for easy handling. The length of chain is measured from one handle to other handle.

Tapes

Tapes are used for more accurate measurements. The tapes are classifiedbased on the materials of which they are made of such as:

1. Cloth or linen tape

2. Fibre tape

3. Metallic tape

4. Steel tape

5. Invar tape

Arrows or chain pins

They are also called as marking or chaining pins and are used to mark the end of chain during the process of chaining. They are made up of good quality hardened and tempered steel wire of 4mm in diameter. The arrows are made400 mm in length. The one pointed part of an arrow is inserted into ground and the other is attached with ring.

Ranging rods or offset rods or ranging poles

Ranging rods or offset rods are round poles made up of wood or metal. These rods are used to range intermediate points of a survey and to set out straight lines on the field when the surveying length is long. The only difference between ranging rods and poles is the length. Ranging rods and offset rods are commonly occurs in 3m length but the ranging poles are available up to 8mlength. The rods possess a metal point at its bottom and the rod or pole is painted with red & white or black & white successive combination. When the survey lines are too lengthy a flag with red/white/yellow colour will be attached to the top of the pole for easy identification.

Pegs

The pegs are made up with wood and they used to mark the survey positions or terminals. The size of the pegs (40 to 60 cm) depends on the type of survey work they are used for and the type of soil they have to be driven in. Although the pegs are driven into the ground 1/5 of its part should be visible on the ground surface.

Plumb-bob

A string suspended with a weight at the bottom will be both vertical and perpendicular to any level plane through which it passes. The plumb consists of a specially designed weight and coarse string or special threads. At one end of the string the weight is affixed. Precisely machined and balanced bobs have pointed tips, and can be made of brass, steel, or other materials, including plastic.

FIELD BOOK

All observations and measurements taken during chain surveying are to be recorded in a standard field book. It is a oblong book of size 200 mm × 120mm, which can be carried in the pocket. There are two forms of the book (i)single line and (ii) double line. The pages of a single book are having a red line along the length of the paper in the middle of the width. It indicates the chain line. All chain-ages are written across it. The space on either side of the line is used for sketching the object and for noting offset distances. In double line book there are two blue lines with a space of 15 to 20 mm is the middle of each book. The space between the two lines is utilized for noting the chain-ages.

Figure shows typical pages of a field books.