MODULE 1- Chapter-1- Introduction to Surveying.ppt

Introduction to surveying

1. INTRODUCTION TO SURVEYING
H. NARENDRA KUMAR,
Associate Professor,
Department of Civil Engineering,
SJBIT
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2. Definition
Surveying is the art of making measurements of
objects on, above or beneath the ground to show
their relative positions on paper. The relative
position required is either horizontal or vertical.
PRIMARY DIVISIONS IN SURVEYING
The survey in which earth’s curvature is considered
is called geodetic surveying and the survey in
which earth’s curvature is neglected is called Plane
surveying.
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3. Differences between Plane
and Geodetic Surveying
PLANE

Effect of the curvature of
the earth surface is
ignored.

The earth surface is
assumed to be plane,
i.e. two dimensional.

Involves smaller areas less
than about 260 km
2
.

Lower degree of accuracy.

Done locally by the
individual organization
Geodetic

Effect of the curvature of the
earth surface is included.

The earth surface is
assumed to be spherical, i.e.
three dimensional.

Involves larger areas more
than about 260 km
2
.

Higher degree of accuracy.

Done by the concerned state
or government department.
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4. Plan and Map
The main Object of the survey is to develop a plan
and a map.
On a plan or a map only horizontal distances are
shown.
The plan or map is made according to chosen scale.
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5. The distinction between a plan and a map is rather arbitrary.
It is difficult to say definitely that when a plan becomes a map
PLAN
A Plan is graphical
representation of features
on or near the earth on a
horizontal plane and here the
scale is large.

Preferably the plans are
prepared for smaller areas to
avoid distortions due to
curvature of the earth.
MAP
A map is Orthographic
representation of features
but differs from plan and here
the scale is small.

Maps are prepared for larger
areas and give some
additional information such as
about the topography with
the help of contours.
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Plan and Map

6. CLASSIFICATION
Surveying may be classified based on the following Four
points:
1.Nature of the field of survey
2. Objects of survey
3. Instrument used
4. The methods employed
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7. On this basis field of survey may be
classified as
a. Land survey,
b. Marine or Hydraulic survey and
c. Astronomical survey.
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Classification Based on Nature
of the Field of Survey

8. Land survey
It involves measurement of various objects on land. This type
of survey may be further classified as given below:

Topographic surveys: They consist of measurement of
various points to plot natural features such as rivers, streams,
lakes, hill and forests as well as man – made features like
roads, railways, towns, villages and canals.

Cadastral survey: These surveys are for marking boundaries
of municipalities, states, etc. the surveys made to mark
properties of individual also come under this category.

City survey: The surveys made in connection with the
construction of streets, water supply and sewage lines fall
under this category.
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9. Marine or Hydrographic Surveys and
Astronomical Surveys
Marine or Hydrographic Surveys: The survey conducted to find
depth of water at various points in bodies of water like sea, river
and lakes fall under this category of surveying.
Finding depth of water at specified points is known as
soundings.
Astronomical Surveys: Observations made to heavenly bodies
like sun and stars to locate absolute position of points on the
earth and for the purpose of calculating local times is known as
astronomical survey.
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10. Classification Based on Object of Surveying
On the basis of objective of surveying, the
classification can be as
a. Engineering survey
b. Military survey
c. Mines survey
d. Geological survey
e. Archaeological survey.
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11. 1.Engineering survey: The objective of this type of surveying is
to collect data for designing roads, railways, irrigation, water
supply and sewage disposal projects.

These surveys may be further subdivided into:

Reconnaissance survey for determining feasibility ad
estimation of the scheme.

Preliminary survey for collecting more information to
estimate the cost o the project selected, and

Location survey to set the work on the ground.
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Classification Based on Object of Surveying

12. 2. Military Survey: This survey is meant for
working out points of strategic importance.
3. Mine survey: This is used for exploring mineral
wealth.
4. Geological survey: This survey is for finding
different strata in the earth’s crust.
5. Archaeological survey: This survey is for
unearthing relics of antiquity.
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Classification Based on Object of Surveying

13. Based on the instruments used
Surveying may be classified into the following:
1. Chain Survey
2. Compass Survey
3. Plane Table Survey
4. Theodolite Survey
5. Tacheometric Survey
6. Modern Survey using electronic equipment like
distance metres and total stations.
7. Photographic and Aerial Survey.
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14. Classification Based on the Methods Employed
Based on the methods employed,
Surveying may be classified as triangulation and
traversing.
1. Triangulation: In this method control points are
established through a network of triangles
2. Traversing: In this scheme of control points consist of
a series of connected points established through linear
and angular measurements. If last line meets the
starting point it is called as closed traverse. If it does
not meet, it is known as open traverse.
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15. PRINCIPLES OF SURVEYING

To get accurate results one should follow the two basic principles explained below:
1. Work from whole to part
In surveying large areas, a system of control points is identified
and they are located with high precision.
Then secondary control points are located using less precise
methods.
With respect the secondary control point’s details of the localized
areas are measured and plotted.
This is called working from whole to part.
This principle in surveying helps in localizing the errors.
If the surveying is carried out by adding localized areas, errors
accumulate.
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16. 1. Work from whole to part
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17. 2. Fixing positions of new control points
For fixing new control points with respect to already fixed
points, at least two independent processes should be
followed. IF A and B are two already located control points
and with respect to them new control point C is to be
located, apart from the minimum two measurements
required, one more reading should be taken. Fixing of check
lines and tie lines will also serve this purpose.

The relative position of any point C can be measured with
reference to the points A and B by one of the following
methods, Linear measurement Angular
■ ■
measurement Both
■
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18. 2. Fixing positions of new control points

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19. SURVEY OF INDIA AND
TOPOLOGICAL MAPS
The survey of India is the oldest scientific department of
Government of India.

It was established in 1767 by the East India Company which was ruling
India at that time.

It works under the Department of Science and technology.

It is assigned the role of a principal mapping agency of the country.

The survey of India ensures that the countries domain is explored and
mapped suitably and provides base maps for expeditions and
integrated development.

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20. SURVEY OF INDIA AND
TOPOLOGICAL MAPS
Bit by bit of Indian terrain was completed by painstaking efforts
of batches of surveyors appointed by East India Company.
Efforts of batches lead by Lambton and Sir George Everest are
noteworthy.
The topological maps prepared by the survey of India are
continuously updated adding more features and more
precision by using better equipment and mapping techniques.
The maps prepared meet the needs of defense forces, planners
and the scientists in the field of geosciences, land and
resource management.
The survey of India had five directorates in 1950.
Presently the number has grown to eighteen.
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21. Numbering of Topo Maps of India
The entire area covered by India is divided into A 4
0
* 4
0
longitude
and latitude and each grid is numbered as shown in Fig.
Each grid is further divided in 4 * 4 grid of size 1
0
*1
0
longitude
and latitude and they are numbered as shown in Fig.
The scale used for 4
0
* 4
0
grid map is 1:25000 and
The scale used for 1
0
*1
0
grid maps is 1:50,000 the 1
0
*1
0

longitudinal and lateral grids are further divided in 15’ * 15’
grids and are numbered.
These maps are available in 1:50,000 to 1:25000 scales.
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23. 09/16/25 23
A map corresponding to 55
th
A of 6
th
grid is
referred to as NH 55 A – 6, where NH refers
to Northern Hemisphere.

24. CHARACTER OF WORK
The character of work of a surveyor may
be divided into three distinct parts:
1.Adjustment and Care of the instruments
2.Field Work and recording Field Notes
3.Office Work
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25. 1. Adjustments and care of instruments:

The adjustment of a surveying instrument means the bringing of
fixed parts of the instrument into proper relation with one another.

For this, a surveyor should understand the principles on which
adjustments are based, the process by which a faulty adjustment is
discovered, the effect or the adjustment on the instrument and the
order of the adjustments.

Keeping the instruments in adjustment is logical for accurate field
work.

This necessitates that some parts of the surveying instruments
should be adjustable.

A proper care of the instrument keeps it in a fit condition for its
usage.
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26. Following are a few suggestions to be kept in mind while using the
surveying instruments:
(a) The chain should be checked for its links, rings and length before its use. All
the knots and kinks should be removed by giving gentle jerks while laying it
on the field.
(b) Tape should be kept straight when in use.
(c) The staff and rod should be either placed upright or supported for the entire
length when in use.
(d) The instrument should be removed from and placed gently in the box.
(e) The instrument should be protected from vibration and impact.
(f) The tripod legs should not be set too close together and should he planted
firmly on the ground.
(g) During observation, the surveyor should see to it that the tripod is not
disturbed.
(h) The various clamping and adjusting screws should not be tightened far more
than necessary.
(i) The objective and eye piece lens should not be touched with fingers.
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27. 2. Field Work
The field work consists of the measurement of angles and
distances and the keeping of a record of what has been done in
the form of field notes.
Field notes are the written records of field work made at the time
the work is done. The field notes must be complete and accurate
as far as possible.
The importance, accuracy, legibility, integrity, arrangement and
clarity that the field notes should have must be over emphasized.
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28. Field Book
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29. Leveling Book
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30. 3. Office Work
The office work of a surveyor consists of
1.Drafting
2.Computing
3.Designing
The drafting mainly consists of preparations of the plans
and sections ( or plotting measurements to some scale)
and to prepare topographic maps. The computing is of
two kinds: i. that done for purposes of plotting and ii. That
done for determining areas and volumes. The surveyor
may also be called upon to do some design work specially
in the case of route surveying.
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31. SCALES
The area that is surveyed is vast and therefore, plans are
made to some scale.
Scale is the fixed ratio that every distance on the plan bears

with corresponding distance on the ground.
Scales can be represented by the following methods:
1.One cm on the plan represents some metres on the ground, such
as 1 cm = 10 m, 1 cm = 50 m, etc. This type of scale is called
Engineer’s Scale.
2.One unit of length on the plan represents some number of same
units of length on the ground, such as 1/100, 1/1000 etc. The ratio
of map distance to the corresponding ground distance is
independent of units of measurement and is called
Representative Fraction.
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32. Representative Fraction
The Representative Fraction (R.F) can be very easily found for a given
Engineer’s Scale.
For eg., if the scale is 1 cm = 50 m.
R.F = 1 cm = 1/5000
(50 X 100) cm
3. An alternative way of representing the scale is to draw on the plan a
Graphical Scale. A graphical scale (diagonal scale) is a line sub-divided into
plan distance corresponding to convenient units of length on the ground.
If the plan or map is to be used after few years, the numerical scales may not
give accurate results if the sheet or paper shrinks. However, if a graphical
scale is also drawn, it will shrink proportionately and the distances can be
found accurately. That is why, scales are always drawn on all survey maps.

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33. SHRUNK SCALE
Shrinkage Ratio or Shrinkage Factor is the ratio of the shrunk
length to the actual length.
Shrunk Scale = Shrinkage Factor X Original Scale
For eg., if the shrinkage factor is equal to 15/16 and if the
original scale is 1/1500, the shrunk scale (will have a R.F) =
(15/16) X (1/1500) = 1/1600
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