Kdul
Kdul
Kdul
Then the distance is measured with the help of time taken for the above process – time taken
by the wave for the emission and return. The wave is travelling along the x axis with a velocity
of 299,792.5 ± 0.4 km/s (in vacuum). The frequency of the wave is, the time taken for one
complete wavelength.
λ = c/f
λ = Wavelength in meters
c = velocity in km/sec.
f = frequency hertz (one cycle per
second)
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Traverse Survey
As per Figure 1.0 shows a modulated electromagnetic wave being emitted from
an EDM instrument and being reflected and being reflected back to the instrument
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Microwave Distance Measurement as illustrated Figure 1.1, the sending (master) instrument
transmits a series of modulated radio waves to the receiving (remote) instrument. The remote
instrument interprets these signals and sends them back to the master unit that measures the
time required for radio waves to make the round trip. The distance is computed based on the
velocity of the radio waves. Because this velocity is affected by atmospheric conditions,
corrections for temperature and barometric pressure are applied according to the operating
instructions provided with the equipment.
• Accuracy = ± 10mm
• Limited line of sight, rain, fog, other airborne particles
The important operations that can be performed using a total station can be listed as follows:
a. Measurement of Distance
An essential component of the total station is Electronic Distance Measuring (EDM)
which is responsible for the distance measurement.
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Traverse Survey
b. The measuring range of the EDM can vary from 2.8km to 4.2km.
• A typical EDM is capable of measuring the distance with an accuracy ranging
between 5mm to 10mm per km of measurement.
• The EDM is equipped with an automatic target recognizer. The distance measured
by the total station is always the sloping distance from the instrument station to
the object.
c. Measurement of Angle
• Another important operation performed by the total station is the measurement
of angle.
• Usually, any suitable direction must be taken as the reference direction for the
measurement of the horizontal angles.
• While, in the case of the vertical angles, the vertically upward direction i.e. the
zenith is taken as the reference direction.
d. Processing of Data
• The processing of data in the total station is done utilizing the microprocessor that is
inbuilt into it.
• The inbuilt microprocessor is capable of averaging the multiple observations taken.
• The microprocessor can compute the horizontal distance as well as the location
coordinates (X, Y, Z).
• In the modern total station, the microprocessor can apply even the pressure
corrections and the temperature corrections when the temperature and the
pressure values are provided.
e. Display of Output
• The output or the computed results are displayed in the total station utilizing the
electronic display unit.
• The display unit can display the computed horizontal distance, vertical distance,
horizontal and vertical angles, elevation differences between points, and the
location coordinates of the required points.
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Objective Lens:
It catches the object being sighted and magnifies the object.
Eyepiece:
It is located at the viewing end of the telescope, it can be turned to bring the crosshairs
into focus.
Focusing Knob:
It is to focus the target when seeing it from the eyepiece.
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Traverse Survey
Leveling Screws:
It allows adjustments to be made to ensure the instrument is level.
Nivo tube
Nivo tube used to determine the erectness of tool.
Base Plate/tribrach:
It is the area to which the instrument level attaches on the tripod.
Tripod:
A tripod is a three-legged stand, important in providing the foundation for auto levels
and other leveling instruments. It is usually made up of Aluminum for the sake
lightness.
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+ Vertical Angle
Horizontal
+ Horizontal Angle
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a. Setting up
It includes fixing the instrument and approximate levelling by leg adjustment
i. Fixing the instrument over tripod
• The clamp screw of the instrument is released.
• The total station is held in the right hand. It is fixed on the tripod by turning round
the lower part with the left hand and it is firmly screwed over the tripod.
Centering Screw
Focussing on the
survey point
Focussing on the
reticle
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Traverse Survey
Equal spacing
Firmly fixed
b. Levelling
The clamp is loosened and the upper plate is turned until the longitudinal axis of the
plate level is parallel to a line joining any two levelling screws, say A and B.
The two foot screws are turned uniformly towards each other or away from each
other until the plate bubble is central.
The telescope is rotated through 90o so that it lies over the third foot screw.
The third screw is turned until the plate bubble is central.
The telescope is rotated through 900 to its original position and the above procedure
is repeated till the bubble remains central in both the positions.
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Traverse Survey
The telescope is now rotated through 1800. The bubble should remain central if the
instrument is in proper adjustment.
c. Elimination of Parallax
It is consists of focussing the eyepiece and objective of the level.
a. Focussing the eyepiece
The operation is done to make the cross-hairs appear distinct and clearly visible.
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Traverse Survey
For this study it is appropriate to know only the basic requirements for permanent adjustments.
The steps in carrying out the adjustments should be handled by the qualified person at the
laboratory.
Even when carefully following established surveying procedures, observations may still contain
errors. Errors, by definition, are the difference between a measured value and its true value.
The true value of a measurement is determined by taking the mean value of a series of
repeated measurements. Surveyors must possess skill in instrument operation and knowledge
of surveying methods to minimize the amount of error in each measurement.
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Traverse Survey
All blunders must be found and eliminated prior to submitting a survey for inclusion in
the project mapping. The surveyor must remain alert and constantly examine
measurements to eliminate these mistakes. Blunders can be detected and eliminated by
reacting to “out-of-tolerance” messages by the data collector when they occur. They can
also be detected by carefully examining a plot of the collected survey points while in the
office.
b. Systematic Errors
Systematic errors are caused by the surveying equipment, observation methods, and
certain environmental factors. Under the same measurement conditions, these errors
will have the same magnitude and direction (positive or negative). Because systematic
errors are repetitive and tend to accumulate in a series of measurements, they are also
referred to as cumulative errors.
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Traverse Survey
Although some systematic errors are difficult to detect, the surveyor must recognize the
conditions that cause such errors. The following list includes several examples of
systematic errors:
• Using incorrect temperature and/or pressure observations.
• Not applying curvature and refraction constants.
• Using incorrect instrument heights and/or target heights.
• Using an incorrect prism offset.
• Using an imperfectly adjusted instrument.
If appropriate corrections are not made, these errors can accumulate and cause
significant discrepancies between measured values. By keeping equipment in proper
working order and following established surveying procedures, many of the systematic
errors can be eliminated.
c. Random Errors
Random (or accidental) errors are not directly related to the conditions or circumstances
of the observation. For a single measurement or a series of measurements, it is the
error remaining after all possible systematic errors and blunders have been eliminated.
As the name implies, random errors are unpredictable and are often caused by factors
beyond the control of the surveyor. Their occurrence, magnitude, and direction (positive
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or negative) cannot be predicted. Errors of this type are compensating and tend to at
least partially cancel themselves mathematically. Because the magnitude is also a
matter of chance they will remain, to some degree, in every measurement.
Random errors conform to the laws of probability and are therefore equally distributed
throughout the survey. Because of their random nature, correction factors cannot be
computed and applied as they are with some systematic errors. However, they can be
estimated using a procedure based on the laws of probability known as the least-
squares method of adjustment. This method computes the most probable adjusted
values and the precision of the survey. The least-squares method may also reveal the
presence of large blunders.
a. Instrument Error
This error is occure due to some faulty in the instruments. There are many types of error cause
by the instrumental faulty.
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b. Personal Error
The error is happening due to manipulation, error in reading and sighting, due to Parallax and
Mistakes in reading and recording. The following list includes several examples of personal
error:
• Instrument not set up exactly over point
• Bubbles not cantered perfectly
• Improper use of clamps and tangent screws
• Poor focusing
• Overly careful sights
• Careless plumbing and placement of rod.
c. Natural Error
Natural error is not due to human error or instrumental error. Although, instrumental error
seems to be natural error but it is already mentioned in the first category. While conducting
theodolite surveying a natural condition should be considered.
Otherwise the following are the error cause for the natural error.
• Error due equal atmosphere temperature which expand the various parts unequally.
• Error due unequal refracted
• Error due to high wind producing vibration
• Error due to unequal settlement of the tripod
Natural error cannot be eliminated, we should take the observation when the situation is
favorable.
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Traverse Survey
Robotic Total Station or Robotic Tachometry System (RTS) widely used for surveying
purpose and solution. From surveyor to archeologist, professional used RTS to solve many
problems in collecting data such as to mapping the land use, archeology excavation site or used
in construction field. Latest technology adopted in modern total station is servo motors to drive
both the horizontal and vertical motion of the instruments. This technology designed special to
search automatically for prism target known as Automatic Target Recognition (ATR). Robotic
total stations allow the operator to control the instrument from a distance via remote control.
This eliminates the need for an assistant staff member as the operator holds the reflector and
controls the total station from the observed point.
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• prepare contour maps which help to determine the capacity of the reservoir, to find the
best possible transportation routes and so on.
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Traverse Survey
• plan and execute engineering projects like bridges, buildings, irrigation canal, and so on.
This field uses highest application of surveying in civil engineering.
• set out and transfer details from map to realistic view to ground
• Detail survey i.e., data collection.
• Control Survey (Traverse).
• Height measurement (Remove elevation measurement- REM).
• Resection.
• Area calculations,
• Missing line measurement (MLM).
The survey procedure known as traversing is fundamental to much survey measurement. The
procedure consists of using a variety of instrument combinations to create polar vectors in
space, that is 'lines' with a magnitude (distance) and direction (bearing). These vectors are
generally contiguous and create a polygon that conforms to various mathematical and
geometrical rules (which can be used to check the fieldwork and computations). The equipment
used generally consists of something to determine direction like a compass or theodolite, and
something to determine distance like a tape or Electromagnetic Distance Meter (EDM).
A traverse, in general, is to locate the features already existing in the area to be survey or in
accordance with predetermined measurements. Travers is classification as both closed and
open.
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Traverse Survey
(a)
(b)
Figure 1.21 : Examples of closed traverses
Closed traverse begins on a point of known position and closes to another point of known
position (often a closed loop on the initial point). (Figure 1.19 (a)) When closing to a different
point of known position, it is called a connecting traverse. (Figure 1.19 (b)) A closed traverse is
employed for locating the boundaries of lakes and woods across which tie lines cannot be
measured, for area determination, control for mapping, and for surveying moderately large
area.
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Traverse Survey
Open traverse begins at a known point and goes to another point whose location is uncertain.
This point cannot be checked for error except by another traverse. It is employed for surveying
long narrow strips of country. E.g.: the path, a highway, railway, canal, pipeline, coastline,
transmission line, etc.
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Traverse survey divide to 4 standard orders. It is used for decided the field procedure and
ensure the required survey equipment and for ensure the survey accuracy before start the
fieldwork of survey. The different classes of traverse have different accuracy.
Each Standard class survey has the accuracy value. Generally, the have four types:
1. General order Traverse
2. First order survey
3. Second order survey
4. Third order survey
Table 1.2: The criteria of standard order survey
Linear Observation Observation Plotted Crossing
Class Closer error
misclosure Distance Bearing Bearing observation
Standard 1:25000 0.001m 1” 10” 1’15”@ 10ps 2
h) The line of sight should be at least 1 m above the ground surface to reduce the
effect of shimmering due to refraction
Nail
Wooden peg
If the traverse stations are to be permanently fixed, the stations mark of concrete block
wit steel bolt indicating the centre of block, should be (fig: 1.24(i)). The station mark is
etched on the bolt. In the mountainous area, the stations mark usually cut in the nature
solid rocks, after marking the stations, their distances from at the least three permanent
reference points around the station should be measured and recorded marking sketch to
relocate the stations at a later stage (fig: 1.24(ii)).
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Traverse Survey
Bolt
Bolt
Solid rock
Concrete
block
(i) (ii)
v. Mark distance
Distance between traverse stations are measured directly by chaining which is a more
reliable method except in rough ground. Each distance must be measured independent
deftly by a 30-meter chain and 20-meter chain separately. Both chains are tested
regularly against standard tapes. When better accuracy is required, steel tape are used
for measuring the traverse legs. In case, measurements by two chains differ by more
than 1 in 1000 in between two stations, the line must be premeasured by both of chain.
The distances given by a 20-meter chain serves only a check on measurement. The
distances measured by a 30 meter, chain is only used in computation. The means of
distances measured by long and short chains should never accept for computation.
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Traverse Survey
Where α is the bearing or azimuth of the traverse course, and distance (H) is the horizontal
distance of the traverse course.
Latitudes (lats) and departures (deps) can be used to calculate the precision of a traverse by
noting the plus/minus closure of both latitudes and departures. If the survey has been perfectly
performed (angle and distance), the plus latitudes will equal the minus latitudes, and the plus
departures will equal the minus departures.
00
Latit (+ve) Latit (+ve)
270 90
180
Figure 1.25 Latitude and departure quadrant
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Traverse Survey
The figure 1.26 is the summary value of Latitudes (lats) and departures (deps) depends to the
value of bearing line.
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Traverse Survey
throughout the traverse instead of being isolated in one or two lines. This only makes a bad job
worse.
There are two procedures commonly used to distribute the misclosure, one based on
experience and knowledge of the survey, the other based on the theory that the misclosure is
proportional to the distance measured.
The two procedures are:
i. Bowditch Method – proportional to line distances.
ii. Transit Method- proportional to ∆E ∆N values
After the latitudes and departures are balanced, the length and bearing of the sides of a
traverse will be slightly changed. The corrected length of each side can be now calculated
LAB = (Dep AB )2 + (Lat AB )2
Adjusted Departure
tan (Bearing) =
Adjusted Latitude
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Traverse Survey
In for all this method, the correction value (positive and negative) refers the total value for
latitude and departure. If the total for latitude is positive (NORTH) grater from total value
latitude (negative (South), then correction value for all latitude (NORTH) is negative and all
latitude negative (SOUTH) is positive. The same process for get Departure correction. Refer
table 1.3 and 1.4.
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Traverse Survey
Table 1.3: Bowditch Method
Latitude Departure Final Final Coordinate
Station Bearing Distance
N S E W Latitude Departure N/S E/W
1 + 0.053 + 0.048
2 16 38 12 252.230 241.672 72.214
+ 0.060 + 0.054
3 73 19 12 284.210 81.576 272.251
- 0.081 - 0.074
4 195 17 30 384.730 371.109 101.466
+ 0.052 - 0.047
1 281 04 36 247.840 47.616 243.223
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3.4.1 Coordinate
Origin point is for refer different values of coordinates from each state in Malaysia. The origin
value for North and East is zero (0). This point is use for reference for all survey work in that
state. The second coordinate point be found depend the calculation of latitudes and
departures value. Therefore, to calculate the next coordinate, you must start from known
coordinate point.
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Table 1.6: The calculation coordinates for closed traverse.
The coordinates for all station reference to station 1 when the values are N1000.000, E1000.000.
Latitude Departure Final Final Coordinate
Station Bearing Distance
N S E W Latitude Departures N/S E/W
1 1000.000 1000.000
Example
Calculate by: ………………………………… Date: ……………………… No. Survey layout: …………………….. No. Sheet : …………….
Diluluskan oleh : ………………………………… Tarikh : ……………………… Buku kerja Luar & Halaman : ………. Mukim : …………….
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3.4.2 Area computation
DMD method – Double Meridian Distance
The best known procedure for calculating a land area with a calculator is the Double Meridian
Distance (DMD) method. This method also uses at Jabatan Ukur dan Pemetaan Malaysia
(JUPEM) to measure the traverse. The meridian distance of a line is the distance; parallel to the
east-west direction, from the midpoint of the line to the reference meridian (usually the north
arrow placed at the most easterly point of the traverse).
To facilitate the calculation, a reference meridian line drawn on the most western point where
it is vertical lines parallel to the north-south. In this case, the meridian through the westerly
point is taken as the reference meridian. The distance between two lines dividing point of two
traverse points and reference meridians called the meridian distance.
The meridian distance for line 1-2, 2-3, 3-4, 4-5 and 5-1 is AA’, BB’, CC’, DD’ and EE’. The
calculations to get the distance meridian for line 2-3 are as below:
Jarak Meridian
Meridian distance
Meridian
Rujukan
Reference
Meridian
Therefore:
Area 123451 = Trapezium 2’233’ + Trapezium 3’344’ + Trapezium 4’450
- 2’21 - 150
= JM2-3 x Latit2-3 + JM3-4 x Latit3-4 + JM4-5 x Latit4-5
- JM1-2 x Latit1-2 – JM5-1 x Latit5-1
The value of meridian distance is half from the value of Final departure, so replace the
value for final departure to formula:
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Table 1.7: The calculation the area use the DMD method – Double Meridian Distance
Start
calculation
43
Coordinate method
Another method to determine the area is to use Coordinate Geometry, often called the COGO
method. This method can use when the traverse station have the coordinate value. The X and
Y coordinates for each point on the traverse are determined using a reference point and adding
the latitudes and departures to the next point as you go around the traverse. Once each point’s
coordinates are determined, the area can be calculated.
Calculation method,
AREA = AREA A23B + AREA B34D + AREA D45E – l AREA A21C – AREA C15E
2 AREA = (T2 + T3)(U2 – U3) + (T3 + T4)(U3 – U4) + (T4 + T5)(U4 – U5) – (T2 + T1)(U2 –
U1) – (T1 + T5)(U1 – U5)
EVALUATE;
2 AREA = (U1T2 + U2T3 + U3T4 + U4T5 + U5T1) – (U2T1 + U3T2 + U4T3 + U5T4 + U1T5)
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Calculation application in practical:
a) Arrange the coordinate:
NORTH EAST
U1 T1
U2 T2
U3 T3
U4 T4
U5 T5
U1 T1
b) Then, cross multiplication the NORTH and East value (left side) and add the total.
Repeat the same process for right side.
c) The area value must get positive. Ignore the negative value.
d) Following is the calculation using this method: (Refer Table 7.4)
= ½ (5339345.817) – (5184365.237)
= ½ (154980.580)
= 77490.290 m2
= 7.749 ha
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EXERCISE
1. A 2nd class traverse survey fieldwork has been formatted at FIVE (5) station. The
observation data from the theodolite are recorded in table below. Calculate the bearing
adjustment and determine the final bearing for each line of the traverse.
Bearing Min
Stn From Stn Final Bearing To Stn
Face Left Face Right Bearing
0
Datum from PC 120 30’ 00’’ 2 1200 30’ 00’’ 1
1 1200 30’ 00’’ 3000 30’ 00’’
2
3 3230 52’ 27’’ 1430 53’ 08’’ 2 3
2
3
4 360 44’ 58’’ 2160 44’ 56’’ 3 4
3
4
5 1320 03’ 49’’ 3120 05’ 22’’ 4 5
4
5
1 2250 21’ 21’’ 450 20’ 00’’ 5 1
5
1
2 3000 30’ 40’’ 1200 30’ 60’’ 1 2
2. Table below shows data for theodolite booking at site. Based on this information, solve:
i. Latitude and departure for each line
ii. Calculate the Arithmetical sum of departure and latitude
iii. Calculate the closing error
46
REFERENCE
Jerry Nathanson (2011), Surveying Fundamentals and Practices. New Jersey: Pearson Education
Inc.
Barry F. Kavanagh, S.J. Glenn Bird (2008), Surveying: Principles and Applications. New Jersey:
Prentice Hall.
Barry F. Kavanagh, Dianne K. Slattery (2015) Surveying with Construction Applications. England.
Pearson education inc.
Jasmee Jaafar, Redzwan Misran, Adli Redzuan Shaary, Roslina Idris, Mohd Nasri Md Rani (2016),
Asas Ukur Kejuruteraan. Shah Alam Malaysia: UiTM.
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