Introduction to surveying (2).pdf

Introduction to Surveying and
Geoinformation Technology
7/11/2022
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Presented By:
Er. Nabaraj Subedi
Instructor
LMTC

Surveying
1 . 'Land surveying' has been defined as the art and science of
determining the position of natural and artificial features on, above or
below the earth's surface; and representing this information on paper
plans, as figures in report tables or on computer based maps.
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Surveying by Land Survey Act
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Geo-Information Technology
Geoinformation Technology is a science dealing with acquisition,
storage, management, analysis and delivery of geographic and spatially
referenced information.
Geoinformatics is the science and the technology which develops and
uses information science infrastructure to address the problems of
geography, cartography, geosciences and related branches of science
and engineering.
The term Geoinformatics and Geomatics are used interchangeably
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History of Surveying
 Surveying science has a very long and distinguished
history, dating back to the 'rope stretchers' of
Babylonia and the Egyptian dynasties.
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History of Surveying
• Around 4000BCE the Babylonians were already
making records of land ownership on clay tablets which
contained the measurements of the land and the
signature of the 'surveyor'.
• Around 2780BCE the pyramids were constructed using
standard units of measurement and simple devices for
setting out the constructions. Wall frescos in pyramids
depict the 'rope stretchers' re-measuring the Pharo's
lands after the annual Nile floods (for taxation purposes
naturally).
• Astronomy was practiced in Messopotamia, China, the
Pacific, South America.
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History of Surveying Contd…
• From around 600BCE to 400BCE there were major advances made in
philosophic/ scientific/mathematic thought.
• Many of the well known Greek philosopher /mathematicians make
contributions during this period: Pythagoras, Anaximander, Democritus
(600BCE±); Socrates, Plato, Aristoteles, (500-400BCE); Euclid, Archimedes,
Apollonius, Eratosthenes (300BCE±). Eratosthenes determined the radius of
the Earth by measuring shadows at Alexandria and Seyne, and was only about
320km off the radius we use today.
• Also around this period other major civil engineering works were constructed, a
six mile canal was constructed at Mt Athos during Xerxes time, the Romans
constructed aqua appia and via appia, as well as bridges and tunnels
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• Around 150BCE, a school of surveying was established
by the Romans .
• Around 120 BCE Ptolemaios (Ptolomy) produced maps,
and established the doctrine that if the earth was
spherical then a proper representation could be obtained
by a geometrical projection of that surface. He was also
an astronomer and instrument maker, and developed a
cartographic philosophy that lasted centuries.
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• Developments now moved from the Greeks and
Romans to the Arab world, where many of the terms
used in astronomy and navigation today originated
(nadir, azimuth, algebra for example).
• Developments continued in China and in India, regular
contact between these three regions ensured
dissemination of knowledge. Surveying developments
in Europe stagnated until Arab conquests revived
investigations in this area. European research was
generally confined to monasteries and religious orders.
Also during this epoch, there appeared the 'zero' , sine
tables, algebra, tangent functions.....
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• 1400-1700±, developments occurred in telescope design
and construction, measurement of magnetic declination,
measurement of time, standardization of units of
measurement, determination of longitude, surveying
instruments, and reference books written on surveying
methods. Da Vinci, Kepler, Napier, Dürer, Pascal,
Newton, Galileo, Coppernicus.
• Mercator invented the map projection known by his
name and still commonly used.
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• From 1700±, the new age of geodesy begins. Soon we
have differential calculus, logarithms, Descartes'
analytic geometry , sextants, octants, the Harrison's
ships chronometer , the spirit level, micrometer
theodolites, and many other products of the industrial
revolution.
• The 1800s saw the development of photography, then
aerial photography and architectural photography. In
the 1864 Aimé Laussedat made a map of Paris from
photographs taken from rooftops, building the
foundation for photogrammetric mapping as practiced
today. Instruments were designed to aid in the
measurement of photographs for map production.
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• The 1900s saw the rapid development of the mapping
sciences as a result of the two major wars. Aerial
photography and reconnaissance, mapping, radio, radar,
lasers, jet engines, space exploration, the establishment of
geodetic survey networks across the countries.
• The digital revolution is now in progress; satellite
position fixing, measurement by light and radio waves,
imaging from satellite and other spaceborne platforms,
map production from digital images, dynamic real-time
mapping, high speed computing and telecommunications,
3D Visulization, faster computers, network
communications. The list of innovations grows, further
changing the face of geomantic science.
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Nepalese History of Surveying
• Cadastral Surveying:
• Land tax was major income in lichhabi era
• Improved land information system in the period of Jay Sthiti Malla ( BS 1383-
1450)
• BS 1911- 1930 – Dangol Surveys
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• BS 1952 – Sarpat Napi
• Compass Survey from 1963
• Fauji Napi – BS 1980-1996
• Survey Department established in BS 2014
• Land reform programme in 2021, and land act 2019 –
Systematic Cadastral Survey
Nepalese History of Surveying...
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Topographical mapping
• Topographical mapping by Indian government in 1952 0n the scale 1
inch to 1 mile
• Topographical survey Branch – established in 2031
• Land resources maps of land utilization, land capability , land system
at the scale of 1:50000, geological map 1:125000, Climetological map
at 1:250000was prepared using 1:50000 aerial photo in assistance of
Canada.
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•1989- 91- Japan assisted to prepare 81 topographical
maps of Lumbini Zone on scale 1:25000
•Gov of Finland assisted to prepare topo maps of
remaining parts of Nepal in 1991-2001
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NGII in Nepal
• From 2001, EU assisted to prepare digital database of
the 706 topographic maps to prepare NTDB
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Geodetic Survey in Nepal
• Trigonometrical Survey Branch – 2026
• Fundamental station, Fundamental base line and astronomical
observatory in 2032 in Nagarkot
• From 2037 – gravity survey
• Czech Experts established 7 Laplace stations and 14 Azimuth Stations
in 2032 in assistance of UNDP
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• British Army Survey Team established 14 Doppler
stations in 2037 and 68 first order trig point.
• University of Colorodo and Massachusettts Institute of
Technology has established 29 GPS points
• Eastern Nepal and western Nepal Topo mapping project
aided by Government of Finland has established a total
of 101 GPS points.
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Objective of Surveying
• To determine the size and shape of the earth and to
measure the data needed to define the size, position,
shape and contour of any part of the earth and
monitoring any change therein.
• To position the objects in space and time as well as
position and monitor the physical features, structures
and engineering works on, above or below the surface of
the earth.
• To develop, test and calibrate instruments and systems
for the above-mentioned purposes and for other
surveying purposes.
• To acquire and use spatial information from close range,
aerial and satellite imagery and the automation of these
processes
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• To determine the position of the boundaries of public or private land,
including national and international boundaries, and to register those
lands with the appropriate authorities.
• To design, establish and administer geographic information systems
(GIS) and collect, store, analyze, manage, display and disseminate
data.
• To analyze, interpret and integrate spatial objects and phenomena in
GIS, including the visualization and communication of such data in
maps, models and mobile digital devices.
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• To study the natural and social environment, the measurement of
land and marine resources and the use of such data in the planning of
development in urban, rural and regional areas.
• To plan, develop and redevelop property, whether urban or rural and
whether land or buildings.
• To assess value and the manage property, whether urban or rural and
whether land or buildings.
• to plan, measure and manage construction works, including the
estimation of costs.
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Function(Uses) of Surveying
Some of the numerous functions of surveying are given below.
• Topographical maps showing hills, rivers, towns, villages, forests etc.
are prepared by surveying.
• For planning and estimating new engineering projects like water
supply and irrigation schemes, mines, railroads, bridges, transmission
lines, buildings etc. surveying is required.
• Cadastral Map showing the boundaries a field houses and other
properties are prepared by surveying.
• Engineering map showing the position of engineering works like
roads, railways, buildings, dams, canals etc. are prepared through
surveying.
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Function of surveying
• To set out a work and transfer details from map to ground, knowledge
of surveying is used.
• For planning navigation routes and harbors, marine and hydro-graphic
surveying are used.
• To help military strategic planning, military maps are prepared by
surveying.
• For exploring mineral wealth, mine survey is necessary
• To determining different strata in the earth crust, geological surveys
are required
• Archaeological surveys are used to unearth relics of antiquity..
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contd..

Fig: Topographical map of United States
Fig: contour Map
Fig: Cadastral Map of Germany
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Different Terms in
Surveying
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Angle
Angular distance between two directions
Vertical or horizontal
vertical angle - If both rays of angle are in same
vertical plane
• Reference line may be horizontal or zenithal
Horizontal angle -If both rays of angle are in same
horizontal angle
• Reference line may be meridian
• Bearing and azimuth
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Meridian
• Fixed line of reference
• True meridian
• Magnetic meridian
• Grid meridian
• Arbitrary meridian
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Meridian
True Meridian
• True meridian at a point is the great circle passing through that
point and the geographical north and south poles of the earth.
• Or plane passing through that point on the surface of the earth
and containing the earth’s axis of rotation.
• Fixed and determined by astronomical observation
• are lines of longitudes and also called geographic meridian,
astronomic meridian N
S
True meridian
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Meridian
Magnetic meridian
• Direction indicated by freely suspended magnetic needle
• Not fixed , vary with time and location
Grid meridian
• Lines that are parallel to a grid reference meridian (central meridian/true)
Arbitrary meridian
• Meridian in arbitrary direction
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True, Grid North
• True north and grid north coincide along
the longitude of origin of a map but grid
north diverges from true north as we move
away from the origin.
• Grid convergence is the angle between
grid north and true north and thus also
varies depending on position and distance
from the chosen projection origin.
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Magnetic north
• Magnetic north is the direction sensed by a compass; the direction of the
horizontal component of the Earth’s magnetic fleld at a particular point on the
Earth’s surface.
• Magnetic north is a point located hundreds of kilometers from the North Pole
(Northern Canada, 2008) and it is not stationary. Declination is the horizontal
angle between magnetic north and true north.
• The declination in a given area will change slowly over time, possibly as much as
2-2.5 degrees every hundred years or so, depending upon how far from the
magnetic pole it is.
• For this reason when quoting any magnetic bearings, the date and declination used must be
quoted. For example, at 57° N, 3° E on the 12th September 2006 the declination = 1° 44’ W
changing by 0° 9’ E/year.
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True, Grid and Magnetic North
• True north is the direction
towards the geographic
North Pole and is the
direction of all meridians on
a geographic coordinate
reference system (see Figure
). Grid north, however, is
based on the chosen
projected coordinate
reference (‘grid’) system.
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Bearing
• Horizontal angle made by survey line with reference direction.
• True bearing
• Angle with true north
• Magnetic bearing
• Angle with magnetic north
• Grid bearing
• Angle with grid north
• Arbitrary bearing
• Angle with arbitrary north
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Declination and convergence
• Angle between true north and magnetic north is called Declination.
• Lines joining the points of equal declination are Isogonic lines
• Lines joining points of zero declination are called agonic lines
• Angle between true north and grid north is called convergence.
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Designation of bearing
•Bearing can be designated by two ways:
I. Whole circle bearing
II. Quadrantal Bearing (QB)/Reduced Bearing
(RB)
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Whole circle bearing, WCB
• horizontal angle measured in a clockwise direction
from the north line
Survey line WCB
OA 600
OB 1200
OC 2400
A
C
B
o
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Quadrantal Bearing or Reduced Bearing
• Acute angle which the line makes with the meridian.
• Measured from the north point or the south point, whichever is
nearer.
• Can not be greater than 900.
Survey line WCB
OA N600E
OB S450E
OC S600W
OD N400W
600
450
400
600
o
A
B
C
D
N
E
S
W
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Forward and backward bearing
• Bearing in the direction
of survey line is called
forward bearing (F.B.)
• Bearing of line AB,
measured from A toward
B
• Bearing in the opposite
direction of survey line is
called backward/reverse
bearing (B.B.)
• Bearing of line AB,
measured from B toward
A
• F.B – B.B = +-1800
A
B
Line F.B. B.B
AB 800 2600
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Quadrants in projected coordinate system
• Four quadrants
• 1st quadrant- North – East Quadrant ( NE)
• 2nd quadrant – South – East Quadrant (SE)
• 3rd quadrant – South – West quadrant (SW)
• 4th quadrant – North – West quadrant (NW)
E
NE
W
S
N
SE
SW
NW
+ +
- +
- -
+ -
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Coordinates and bearing
• Survey line AB with coordinates A(E1, N1)
and B(E2, N2) respectively.
• Then, β = angle ABX
Tan β = AX/BX
= (E2 – E1)/(N2 – N1)
β = tan-1(∆E/∆N)
E
W
S
N
A
B
X
β
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Coordinates and Quadrants
• In which quadrant does the line joining two points A (355701.234 m,
3054234.456 m) and B (355550.234 m, 3054034.456 m ) lie?
• What is WCB of line joining AB ?
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Bearing and azimuth
• Azimuth is the direction of a line as given by an angle measured
clockwise from the north end of the meridian
• Ranges from 0 degree to 360 degrees
• Bearing can be measured clockwise or counterclockwise from the
north or south end of the meridian.
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Geoid and Reference Ellipsoid
• The level surface which
optimally approximates mean
sea level is denoted as geoid. It
serves as a reference surface for
defining height systems.
Torge, Gravimetry (p. 32)
• The gravity equipotential
surface which best
approximates the (mean) sea
level over the whole Earth.

Geoid and Reference
Ellipsoid
• The geoid may be described as a
surface coinciding with mean
sea-level in oceans, and lying
under the land at the level to
which the sea would reach if
admitted by small frictionless
channels.
• More precisely, it is that
equipotential surface of the
Earth's attraction and rotation
which, on average, coincides
with mean sea-level in the open
ocean
Bomford's Geodesy (p.94),

Geoid and Reference Ellipsoid
• A geoid is a close
representation, physical model,
of the figure of the Earth. It is
the "mathematical figure of the
Earth", of her gravity field.
• But the geoid is not regular
shape that the mathematical
model can be developed to
determine the three
dimensional position of the
points on her surface

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Ellipsoid parameters
Primary ellipsoid parameters
Parameter Name Symbo
l
Description
semi-major axis a Length of the semi-major axis of the ellipsoid, the
radius of the equator.
semi-minor axis b Length of the semi-minor axis of the ellipsoid, the
distance along the ellipsoid axis between equator and
pole.
inverse flattening 1/f = a/(a – b)
a
b

Geoid and Reference
Ellipsoid
• The geoid surface is more
irregular that the ellipsoid of
revolution often used to
approximate the shape of the
physical Earth, but considerably
more smooth than the Earth's
physical surface.
• The ellipsoid of revolution has
excursions of roughly +8,000 m
(Mount Everest) and -11,000 m
(Marianas Trench), the geoid
varies by only approx. ±100 m
about the reference ellipsoid of
revolution.

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Everest Spheroid 1830
• Derived in 1830
• used in India and several adjacent countries
• Named after Sir George Everest
• Semi-major axis, a – 6377276.345 m
• Semi-minor axis, b = 6356075.413 m
• Inverse flattening= 300.8017

Geographical coordinates (latitude and
longitude)
The position of a point isgenerally expressed by
means of geographical coordinates:
latitude (φ) and longitude (λ).These are angular
expressions related to the equator and the
prime meridian, usually, the meridian passing
through Greenwich, London (these being
the 0° references for the N–S/E–W directions
respectively).For example, a typical position
would be expressed as Latitude57°30’15”N, Longitude
3°40’20”W.
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Spherical Triangle
If we wish to connect three points on a plane using the shortest
possible route, we would draw straight lines and hence create a
triangle.
For a sphere, the shortest distance between two points is a great
circle.
Similarly, if we wish to connect three points on the surface of a
sphere using the shortest possible route, we would draw arcs of
great circles and hence create a spherical triangle.
To avoid ambiguities, a triangle drawn on the surface of a sphere is
only a spherical triangle if it has all of the following properties:
 The three sides are all arcs of great circles.
 Any two sides are together greater than the third side.
 The sum of the three angles is greater than 180°.
 Each spherical angle is less than 180°.
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• Denoted as similar as in a plane Triangle
• Angles as A, B and C
• Sides respectively opposite to them are a, b and c
• The sides of spherical triangle are proportional to the angle
subtended by them at the centre of the sphere
• Therefore, the sides are also expressed in angular measure
• The spherical angle A is measured by the plane angle A between the
tangents at A to the arcs AB and AC
Spherical Triangle
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• Formulae in spherical trigonometry
• Sine formula
• Cosine formula
• Other formula
(Pls. Refer the book Higher Surveying, BC Punmia, Vol III)
Spherical Triangle
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Time
• The interval that elapses between any two events is known as time.
• The time is measured with respect to the position of the object in
periodic motion, the motion that occurs repeatedly.
• 1/60th of a complete rotation of the second arm of a clock is called
one second time.
62

Time
• The period that elapses in making one complete revolution by the
stars round the celestial pole is called sideral day.
• The time interval in completing one revolution is equal to 23 hrs 56
min 4 sec.
• The instrument that measures the time is called the clock, watch or
chronograph.
• The clock that keeps the sidereal time is called astronomical clock.
• It records 00 0'0" when  just crosses the meridian, after the interval
of one sidereal day again returns to the meridian.
• The hours in the clocks are reckoned form o hours to 24 hours
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Time
• The passage of heavenly body across the meridian is called its transit
or culmination.
• The rotation of the earth causes the heavenly body to transit or
culminate in succession across the meridian.
• The interval between to consecutive transit of the sun across the
meridian at any place is called Solar Day.
Note:
A sideral day is the time it takes for the earth to rotate about its axis
sothat the distant stars appear in the same position in the sky.
A solar day is the time it takes for the Earth to rotate about its axis so
that the sun appears in the same position in the sky
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Principle of Surveying
The techniques of land surveying are founded on five basic
principles:
Working from whole to the part
Location of the point by measurement from two point of
references
Consistency of work
Economy
Independent check
“Up to date” is aslo considered as one of the fundamental
components in surveying.
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Principles of Surveying
• The first is that of “working from the whole to the part” that is establishing an
initial framework of control points (seemed to be free from error after being
established and adjusted) that is then “broken down” into smaller networks
with points closer together.
• subsequent work is based on this framework by using less elaborate methods,
and adjusted to it
• Errors in small frameworks are localized and are not magnified and the accumulation of
errors is controlled to achieve consistency and accuracy.
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Location of the point by measurement from two point of
references
According to this principle, the relative position of a point to be
surveyed should be located by measurement from at least two points
of reference, the positions of which have already been fixed.
Principles of Surveying contd..
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• The third principle is that of consistency in work.
• Relative standard of accuracy of the linear and angular measurements should
be consistent.
• Precision of angular and linear measurements ( or instruments) should be consistent.
• Methods and instruments for same type of surveys should be of similar
standard.
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• Consistency also refer to
• the precision of different parts of a survey within a properly controlled
framework should be consistent
• final accuracy of a survey is dependent upon the accuracy of the overall
controlling framework together with the precision to which the various parts
have been measured
• subsequent survey can never exceed the accuracy of the controlling framework
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• The fourth and related principle is that of economy,
namely that since higher accuracy in general costs
more money the surveyor should seek no higher
accuracy than is necessary and sufficient for the task
in hand
• Standard of accuracy achieved < the specified  useless
• Accuracy attained > the specified  wastage of time,
money and effort because high accuracy requires very
costly precise instruments, more field work and more
extensive computations.
• So, prior to any survey project, it is essential to weigh the
accuracy which it is hope to attain against the time and
money available
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• The fifth principle is that of applying an
independent check on the data wherever
possible - for example by measuring all three
angles of a triangle even though the third
angle measurement is redundant. This has
the effect of providing built-in quality
control.
• Survey should be conducted so that errors do not pass
undetected – should be suitable provision of checks or survey
work should be self checking.
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• since changes take place over time, mechanisms must be established to
ensure that the survey (data) is kept up to date if it is to be of
continuing use.
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Divisions and
Methods of Surveying

74
Contents
• Primary division of surveying
• Size and shape of earth
• Methods of surveying
• Branches of surveying
• More classifications of surveying

75
Primary division of surveying
Made on the basis whether the curvature of the earth is considered or
not
• Plane surveying
• Geodetic surveying

76
Plane Surveying
• refers to the surveys of small
extent where it is assumed
that the mean surface of the
earth is a horizontal plane for
the area concerned
• The curvature of the earth is
neglected
• Gravity direction is
considered parallel through
out the survey region.
• Shortest distance between
points is straight line
A + B + C = 1800

77
Geodetic surveying
• refers to surveys of larger
areas where the above
assumption of the earth as a
horizontal plane is invalid
and allowance must be made
for the curvature of the
earth.
• Gravity lines are not parallel
and concentric toward centre
of earth.
• Shortest distances are
curved lines.

78
Plane and geodetic … comparison
• For small area plane and
geodetic surveying are
similar ( < 250 sq. km).
18.5 km – L < 10 mm
A’+B’+C’-(A+B+C) = 1 sec

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Plane Surveying
• A+B+C = 180°; A,B,C are plane angles
• Sine Rule
• Plumb lines parallel
• Cosine rule
• For small area
• Surveys for the location and construction of
highways, railways, canals
C
B Sin
c
Sin
b
SinA
a


bc
a
c
Cos
2
b
A
2
2
2




80
Geodetic survey
• A+B+C = 180°+ Spherical excess; A,B,C – Spherical
angles
• Sine Rule
• Plumb lines not parallel; level lines- curved
• Cosine rule
• For large area
C
sin
B Sin
c
Sin
Sinb
SinA
Sina


c
sin
sin
cos
cos
A
b
c
b
Cosa
Cos


a
C
B A
c
b

81
Geodetic Surveying
The object of the geodetic survey is to determine the precise position
the surface of the earth, of a system of widely distant points which
form control stations to which surveys of less Precision may be
referred.

82
Geodetic and plane surveying
• Field measurements for geodetic surveys are usually
performed to a higher order of accuracy than those of
plane surveys.
• Geodetic surveying, the curved surface of the earth is
considered by performing the computations on an
ellipsoid.
• It is now becoming common to do geodetic
computations in a three-dimensional, earth-centered
Cartesian coordinate systems.
• Geodetic methods : to determine relative positions of
widely spaced monuments and to compute lengths and
directions of the long lines between them.

83
Methods of surveying
• From two known
points of reference, the
location of a point to
be surveyed can be
surveyed by the
following methods
1. By measuring the two
distances from that
point to the known
reference points.
• very much applied in
chain surveying.
• Basis of control
surveying “Trilateration”

84
Trilateration
• Method of control
surveying where points
are established by
measuring all three sides
of triangle.

85
Method of surveying
2. By measuring
• perpendicular distance
from a point to be
surveyed to that line of
joining two known
reference known points
and
• Distance of foot of
perpendicular from one
of two points.
• The length of
perpendicular is called
offset.

86
Methods of Surveying
3. By measuring
• The distance of point
from one of two known
points and
• Angle made by this
distance with line
joining these known
points.
• Used for detailing
and
• Equally applicable
for control points
extension as well –
Traversing

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Method of Surveying
• Traversing
• Directions and distances
of serially connected lines
are measured.

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Method of Surveying
4. By measuring two
angles made by lines
joining point and
known reference points
with line joining the
two known points.
• Basis for control point
fixing by triangulation
and intersection method
• Extensively used for
detailing by intersection
method.

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Triangulation
• Method of control points establishing where three
angles of triangle are measured

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Methods of surveying
• There exits one more
method but different
from above methods as it
uses at least three known
reference points instated
of two as above.
• Measurement of angles at
the point to be surveyed
between the known
points
• Used for control point
fixing rather than
detailing & called
Resection.

91
Branches of Surveying
• Control surveying
• Topographic surveying
• Cadastral surveying
• Engineering surveying
• Hydrographic surveying
• Photogrammetric surveying
• Remote Sensing
• Geographical Information System (GIS)
• Global Positioning System

92
• measurements for the provision
of the main framework of survey
control marks which covers a
wide area and from which all
topographical, cadastral and
engineering surveys are based on.
Control Surveying

93
Control Surveying
• The framework of a survey is usually fixed by employing one of the
following methods:
– Triangulation
– Resection
– Intersection
– Trilateration
– Traversing
– levelling
– Global Positioning System
– Combination of the above.

94
Triangulation
• Traditional means for establishing control principle behind which is
that of simple trigonometry to find precise size and shape of the
triangle.
• Measurements of angles are made using a theodolite while distances
which in the past had to be measured very laboriously with metal
tapes are now recorded using electronic distance measuring devices.
• Primary network of control points in turn were used as the basis for
determining a series of second order networks; these in turn were
used to establish third order and fourth order points with local detail
being fixed in relation to the overall network.

95
Triangulation
• Triangulation using AB
as a base line
The distance AB is
measured precisely
Then C, D, E, F, G, H, I,
J and K can be fixed by
angular measurement
only.

96
Control surveying
• Given an initial framework of horizontal control points, additional
points can be established either by further
• triangulation, or by
• trilateration (that is measuring the sides rather than the angles of triangles),
or by
• traversing.
• In addition, satellite position fixing methods or photogrammetric techniques
can be used.

97
Traversing
• Traversing is a method frequently used for surveying perimeters, or for defining
an area for subsequent more detailed survey, or for plotting the course of a road,
railway, stream or other feature.
• The method starts at a known point from which there is a known direction - for
example a point already established by triangulation from which another known
point is visible to provide the necessary orientation.
• Traversing then proceeds by measuring the angle and linear distance to the next
point on the traverse; from there the bearings can be oriented from the previous
point and a further control point established in a forward direction.
• .

98
Traversing
• The traverse proceeds in this way until either it can be closed back on
to the point from which it started, or preferably on to a different
previously established control point thus providing the necessary
independent check against any gross error in the measurements.
• The angles are normally measured with a theodolite although a
prismatic compass or a plane table can be used for elementary
surveys. Distances should either be measured by tape with a steel
band, by optical distance methods such as the subtense bar, or by
electronic distance measurement. The data are either recorded in
field notebooks or else electronically for subsequent computation

99
Traversing
• Traversing between
known points A and B
using known points C
and D for orientation and
fixing E, F, G and H by
measuring angles and
distances

100
Closed Traverse: Geometrically Closed
A
H
G
F
E
D
C
B
Control station
Traverse station

101
Closed Traverse: Geometrically Open
A
H
G
F
E
D
C
B
Control station
Traverse station

102
Levelling
• Control survey for height control
• uses a spirit level and two graduated staves
• very precise measures of the difference of height between successive
points.
• by starting at points of known height, the levels can be transferred
successively until another known point is reached which can be used
to check that no gross error has occurred.

103
Topographical Surveying
• Measurements of natural
and artificial features of
the earth surface, and
their relative positions
and the fixing of heights
and contours above a
fixed datum, usually in
order that a map of these
features may be made -
topographical map.

104
Cadastral
Survey
• process of defining,
marking, measuring and
recording the boundaries
of properties.
• Cadastral work is usually
more precise than
topographical surveying.

105
Engineering Surveying
• Work done for engineering
projects, before, during and after
construction.
• The methods ranges from those
used for topographical surveys
to those used for surveys where
a very high order of accuracy is
required.

106
Hydrographic Surveying
• concerned with the bodies of
water, such as harbours, lakes,
rivers and the sea.
• Includes all surveys made to
determine the depth of water,
the characteristics of an
underwater surface, changes in
water level or the discharge of
a river or stream.

107
Photogrammetric Surveying
• Utilization of the science of measurement from stereoscopic
photography to determining the relative position of the natural and
artificial features of the earth's surface' and obtaining elevations
above a given datum.

108
Aerial Photography
• Photographs taken from
cameras mounted on aircraft
(analogue/digital nowadays)
• Oldest and yet most
commonly applied Remote
Sensing technique
• Stereo capability
• Most commonly used for
topographic mapping
• Wide range of applications in
different types of thematic
mapping
108
Beechcraft King Air C90A

109
Aerial photography
109
60% forward overlap 20 - 30% side lap
Flight strip 1
Flight strip 2

110
Remote Sensing
• The process of detecting
and/or monitoring the
chemical or physical
properties of an object
without physically
contacting the object

112
Geographic Information System
• designed to accept large
volume of spatial data, derived
from a variety of sources, and
to efficiently store, retrieve,
manipulate, analyze and
display these data according to
user-defined specifications.

113
Global Positioning
System
• GPS uses satellites in the sky,
the signals from which are
picked up by the GPS
receiver.
• The signals are marked with
pulses at known times so that
the instant at which three
signals are received provides
information on how far away
the satellites were at that time
• measurement to a fourth
satellite is needed to establish
the difference in time
between the clock in the GPS
receiver and the time being
recorded by the satellite
system.

114
Global Positioning System
• The system overall allows the relative positions of nearby points on
the ground to be determined to within a few centimetres in latitude,
longitude and height.
• Since a good all-round view of the sky is necessary, the technique is
not suitable for forest or jungle areas or within city centers where
there are many high-rise buildings.
• In open countryside it is, however, extremely useful and cost
effective for establishing dense networks of control points.

116
Classification of surveying Based on instrument used
 Chain survey
– Using chain and tape used
– Simplest type
– Only linear measurements
are taken
 Compass Survey
– Use of compass for
measuring Bearing
– Use of Tape for distance
measuring

117
Classification of….
 Levelling
• Level is used to determine
height difference
 Plane table survey
• Plane table are used to
measure and plot
simultaneously

118
Classification of…..
• Tacheometric survey
• Tacheometer (theodolite fitted with stadia hair) is used to find relative
positions between points on earth.
• Extensively used in engineering survey

Classification of…..
 Theodolite Survey
• Traverse
• Triangulation
 Photogrammetric Survey
 Use of aerial photograph for
making map
 Total Station Survey
 Use of Total Station Instrument.
 GPS Survey
119

FIG Definition of the Functions of the Surveyor
Who is surveyor?
A surveyor is a professional person with the academic qualifications
and technical expertise to conduct one, or more, of the following
activities;
 to determine, measure and represent land, three-dimensional objects,
point-fields and trajectories;
 to assemble and interpret land and geographically related information,
 to use that information for the planning and efficient administration of
the land, the sea and any structures thereon; and,
 to conduct research into the above practices and to develop them.
7/11/2022 120

7/11/2022 121
Detailed Functions (FIG)
•
The surveyor’s professional tasks may involve one or more of the following
activities which may occur either on, above or below the surface of the land
or the sea and may be carried out in association with other professionals.
1. The determination of the size and shape of the earth and the measurement of all data
needed to define the size, position, shape and contour of any part of the earth and
monitoringanychange therein.
2. The positioning of objects in space and time as well as the positioning and monitoring
of physical features, structures and engineering works on, above or below the surface
oftheearth.
3. The development, testing and calibration of sensors, instruments and systems for the
above-mentionedpurposesandforothersurveying purposes.
4. The acquisition and use of spatial information from close range, aerial and satellite
imageryandtheautomationof theseprocesses.
5. The determination of the position of the boundaries of public or private land,
includingnational and international boundaries, and the registration of thoselands with
theappropriateauthorities.

6) Thedesign,establishmentandadministrationofgeographicinformationsystems(GIS)andthe
collection,storage,analysis,management,displayanddisseminationofdata.
7) Theanalysis,interpretationandintegrationofspatialobjectsandphenomenainGIS,includingthe
visualisationandcommunicationofsuchdatainmaps,modelsandmobiledigitaldevices.
8) Thestudyofthenaturalandsocialenvironment,themeasurementoflandandmarineresourcesand
theuseofsuchdataintheplanningofdevelopmentinurban,ruralandregionalareas.
9) Theplanning,developmentandredevelopmentofproperty,whetherurbanorruralandwhetherland
orbuildings.
10)Theassessmentofvalueandthemanagementofproperty,whetherurbanorruralandwhetherland
orbuildings.
11) Theplanning,measurementandmanagementofconstructionworks,includingtheestimationof
costs.
Intheapplicationoftheforegoingactivitiessurveyorstakeintoaccounttherelevantlegal,economic,
environmentalandsocialaspectsaffectingeachproject.
7/11/2022 122

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