Traversing final-report

TAYLOR’S UNIVERSITY | SABD | SITE SURVEYING (QSB 60103) | TRAVERSING REPORT

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SCHOOL OF ARCHITECTURE, BUILDING AND DESIGN

BACHELOR OF QUANTITY SURVEYING (HONOURS)

QSB 60103 – SITE SURVEYING

SEMESTER 2

FIELDWORK 1 REPORT

TRAVERSING

Name Student ID Marks

Hor Weng Lim 0319441

Felix Vong Zhi Wei 0318462

Kevin Lee Hee Xian 0315192

Jackson Ting Shii Hang 0324326


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Content Page

Cover Page 1

Table of Content 2

1.0 Introduction to Traversing 3

1.1 Open Traverse 3

1.2 Closed Traverse 4 - 5

1.3 Northing 6

1.4 Azimuths 7

1.5 Bearing 8

2.0 Objective 9

3.0 Outline of Apparatus 10

3.1 Theodolites 10

3.2 Tripod Stand 11

3.3 Optical Plummet 12

3.4 Ranging Rod 13

3.5 Spirit Bubble 14

3.6 Plumb Bob 15

4.0 Field Data 16

4.1 Compute the Angular Error and Adjust the Angles 17

4.2 Stadia Method 18 - 19

4.3 Compute Course Bearing and Azimuth 20

4.4 Compute Course Latitude and Departure 21

4.5 Determine the Error of Closure 22

4.6 Adjust Course Latitude and Departure 23

5.0 Discussion 24

6.0 Conclusion 25


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1.0 INTRODUCTION TO TRAVERSING

Traversing is a form of a control survey that requires the establishment of a series of stations that

are linked together by angles and distance. It can be open traverse and close traverse. The angles

are measured by theodolites and the distance can be measured by calculating the stadia’s reading

or using electronic distance measuring equipment. The use of theodolites in traversing survey is

one of the most common methods in engineering work to get the provision of control surveys,

angle measurement and detail mapping.

1.1 OPEN TRAVERSE

Figure 1.0: Open Traverse

Sources: http://mygeosurvey.blogspot.my/

Open traverse is a series of measured straight lunes and angles that do not geometrically close or

a surveying traverse that fails to terminate at the starting point and does not completely enclose a

polygon. It ends at a station whose relative position is not previously known. It is the least

desirable type of traverse because it provides no check on fieldwork or starting data.

http://mygeosurvey.blogspot.my/


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1.2 CLOSED TRAVERSE

Closed traverse is a series of connected line which end at the starting point. It is basically a

traverse proceed from one coordinate point to another. A closed traverse may be close back to its

starting point or whose relative position is known.

Closed traverse can be in two types:

Closed Loop Traverse

Figure 1.1: Closed loop Traverse

Sources: http://mygeosurvey.blogspot.my/

A closed loop traverse starts and ends on the starting point with assumed coordinates and azimuth

without affecting the area, computations or relative position of the stations. It usually need at least

4 point to conduct this survey. The coordinates must be tied to an existing grid system and the

traverse must start from a known station which is azimuth on that system. Closed loop traverse

provides some check upon fieldwork and computations, it does not provide for check of data that

may cause systematic error during the survey.

http://mygeosurvey.blogspot.my/


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Closed Connecting Traverse

Figure 1.2: Closed Connecting Traverse

Sources: http://www.globalsecurity.org/military/library/policy/army/fm/6-2/fig5-6.gif

A closed connecting traverse is almost looks like an open traverse, the only different between

closed loop traverse and closed connecting traverse is it begins and ends at points or lines of

known position and the direction at each of the particular traverse.

http://www.globalsecurity.org/military/library/policy/army/fm/6-2/fig5-6.gif


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1.3 NORTHING

There are 3 reference direction or datum meridian that are used as traverse reference. Which is

Magnetic North, Grid North and True North (Geodetic North).

Magnetic North

Angle are measured from magnetic north. Since magnetic fields fluctuate over time, this

meridian is time-dependent. The magnetic fields will orientate a free swinging magnetic

needle in a north or south direction.

Grid North

A grid of lines parallel to the true meridian of one point on the grid, usually the origin of

the grid. The angle is dependent on the map projection. Since the central meridian point

to true north, when we move east or west away from the meridian, the difference between

grid north and true north will increases.

True North

True North is the direction along the earth’s surface towards to the geographic North Pole

which all the lines of longitude converge. Historically south has occasionally been used.


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1.4 AZIMUTHS

Figure 1.3: Azimuths

Sources: http://www.engr.mun.ca/~sitotaw/Site/Fall2007_files/TP_Lecture9_CloseTravers-

ENGI3703.pdf

Azimuths defined as horizontal angles turned clockwise from the reference line. Which is

between the ranges from 0° to 360°. For example: 128°, 239° and 351°. Generally, the angles

should be measured only from the north.

http://www.engr.mun.ca/~sitotaw/Site/Fall2007_files/TP_Lecture9_CloseTravers-ENGI3703.pdf



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1.5 BEARINGS

Figure 1.4: Bearings

Sources: http://www.engr.mun.ca/~sitotaw/Site/Fall2007_files/TP_Lecture9_CloseTravers-

ENGI3703.pdf

Bearings is defined as an acute angle which is less than 90°. It is a horizontal angles measured

from the meridian either east or west. Usually required two letter with an acute angle which is

North (N), South (S), East (E) & West (W). The different between azimuths and bearing is

bearing can be measured both either clockwise or counter clockwise. It can be measured from

North or South axis of the meridian.




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2.0 OBJECTIVE

To learn the principles of running a closed field traverse.

To enhance students’ knowledge in traversing procedure.

To establish ground control for photographic mapping.

To enable students to get hands-on experience in setting up and working with the

theodolites, leveling rod, tripod stand as well as other instruments and collect the data of

the relevant fieldwork.

To allow students to learn the correct method in doing traversing,

To allow students to apply the theories that had been taught in classes to a hands-on

situation.

To enable students to identify the error and make adjustment to the data by using the

correct formula.

Learn how to compute a traverse and properly adjust the measured values of a closed

traverse to achieve mathematical closure.

Determine the error of closure and compute the accuracy of work.


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3.0 OUTLINE OF APPARATUS

3.1 THEODOLITE

Figure 1.5: Theodolite

Sources: http://www.visurveyinstruments.co.za/image/cache/data/DT-209-500x500.jpg

Theodolite is a precision instrument for measuring angles in both horizontal and vertical planes. It

is used to identify the ground level and the ways to construct super structure or sub structure. A

theodolites consists of a small sized movable telescope mounted within two perpendicular axis

which are horizontal and vertical axis. It also able to rotate 360 degree on a tripod stand that’s

where we get angles from it. When the telescope is pointed at a target object, the angle of each

axis can be measured with great precision. It is commonly used to measure horizontal and vertical

angles, ranging and leveling as well as controlling verticality.

http://www.visurveyinstruments.co.za/image/cache/data/DT-209-500x500.jpg


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3.2 TRIPOD STAND

Figure 1.6: Tripod Stand

Sources: http://www.toolup.com/product-images/2161_1.jpg

A tripod stand is a three-legged support platform for the level. The main function of the tripod

stand is to ensure a stable instrument setup for reliable measurements. The legs of the tripod can

be adjust to get the vertical height that required. Once the instrument is moved, then it must be set

up again which is to loosen the screw and adjust again and lock it back tight. It usually has a flat

tip and a mounting screw for instrument attachment. It is also to make sure that the leveling tripod

placed horizontally.

.

http://www.toolup.com/product-images/2161_1.jpg


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3.3 OPTICAL PLUMMET

Figure 1.7: Optical Plummet

Sources: https://www.hayesinstrument.com/accs_TopconTribrachOP.jpg

Optical Plummets is a device that used to center the instrument over a ground station. It is used in

place of a plumb bob to center transits and theodolites over a given point, preferred for its

steadiness in strong winds. The procedure speeds up the setting up process as well as protect the

instrument from accident, because it has a lock below the optical plummet to lock the devices that

used in fieldwork. Sometimes, the optical plummet can be used to perform angular or distance

measurements from the survey point.

https://www.hayesinstrument.com/accs_TopconTribrachOP.jpg


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3.4 RANGING ROD

Figure 1.8: Ranging Rod

Sources: http://3.imimg.com/data3/JA/BD/MY-2853543/steel-ranging-rods-500x500.jpg

Ranging rod is used to mark areas and to set out straight lines on the field. It is also used to mark

points that must be seen from a distance. The length of the ranging rod is either 2m or 3m. It is

made up of wood or metal. Ranging rod usually painted with alternate red-white or black-white

bands.

http://3.imimg.com/data3/JA/BD/MY-2853543/steel-ranging-rods-500x500.jpg


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3.5 SPIRIT BUBBLE

Figure 1.8: Spirit Bubble

Sources: http://g02.a.alicdn.com/kf/HTB1nZ8OJXXXXXaZXpXXq6xXFXXXw/34-20-12mm-

Metal-Bullseye-Level-Circular-vials-Bubble-Spirit-Level-with-Mounting-holes-Accuracy-8.jpg

The spirit bubble is used for maintaining both level rods and sighting poles in a vertical position.

An out of adjustment of spirit bubble level will cause accumulative error in level lines. It can used

in traversing and leveling measurements in fieldworks. In order to get an accurate measurement

for both, the spirit bubble level must be inside the middle of the black circle. It is located on the

optical plummet and leveling rod.

http://g02.a.alicdn.com/kf/HTB1nZ8OJXXXXXaZXpXXq6xXFXXXw/34-20-12mm-Metal-Bullseye-Level-Circular-vials-Bubble-Spirit-Level-with-Mounting-holes-Accuracy-8.jpg

http://g02.a.alicdn.com/kf/HTB1nZ8OJXXXXXaZXpXXq6xXFXXXw/34-20-12mm-Metal-Bullseye-Level-Circular-vials-Bubble-Spirit-Level-with-Mounting-holes-Accuracy-8.jpg


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3.6 PLUMB BOB

Figure 1.9: Plumb Bob

Sources: https://www.pinterest.com/pin/537687642987491772/

Plumb bob is used to check if the object are vertical. A plumb bob consist of a piece of metal

pointing downwards, which is attached to cord. It is normally tie on the optical plummet by using

the string. When the plumb bob is hanging free and not moving, the cord is vertical. It is used to

mark a point directly under theodolite as well.

https://www.pinterest.com/pin/537687642987491772/


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4.0 Field Data

Station Field Angles

A 86° 44’ 20’’

B 92° 39’ 40’’

C 86° 46’ 20’’

D 93° 46’ 40’’

Total 357° 175’ 120’’

359° 57’ 00’


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4.1 COMPUTE THE ANGULAR ERROR AND ADJUST THE ANGLES

The sum of the interior angles in any loop traverse must equal to 360°.

Total angular error = 360° - 359° 57’ 00’’

= 00° 03’ 00’’

Error per angle = 00° 03’ 00’’ / 4

= 00° 00’ 45’’ / 45’’ per angle

Station Field Angle Correction Adjusted Angles

A 86° 44’ 20’’ + 00° 00’ 45’’ 86° 45’ 05’’

B 92° 39’ 40’’ + 00° 00’ 45’’ 92° 40’ 25’’

C 86° 46’ 20’’ + 00° 00’ 45’’ 86° 47’ 05’’

D 93° 46’ 40’’ + 00° 00’ 45’’ 93° 47’ 25’’

Total 357° 175’ 120’’ 357° 179’ 60’’

359° 57’ 00’ 360° 00’ 00’’


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4.2 STADIA METHOD

We can use stadia method to calculate the distances between the points. The horizontal and

vertical distances between the survey points and the theodolites can be calculated using the

equation.

The differences between the top stadia readings and the bottom stadia readings must be the same

while conducting the survey.

Equation

D = K x S x Cos2 (θ) + C x Cos

D = Horizontal distance between survey point and instrument

S = Difference between top stadia and bottom stadia

θ = Vertical angle of telescope from the horizontal line when capturing the stadia readings.

K = Multiplying constant given by the manufacturer of the theodolite, normally 100

C = Addictive factor given by the manufacturer of the theodolite, normally 0


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We can calculate the distance by using stadia method which is use top stadia and bottom stadia

readings.

The calculation of the stadia method is below follow by the distance:

Dab = 100 x (0.4887) x Cos2 (0) + 0 x Cos (0) = 48.8626m

Dbc = 100 x (0.29355) x Cos2 (0) + 0 x Cos (0) = 29.3505m

Dcd = 100 x (0.4795) x Cos2 (0) + 0 x Cos (0) = 47.9427m

Dda = 100 x (0.2989) x Cos2 (0) + 0 x Cos (0) = 29.8854m


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4.3 COMPUTE COURSE BEARING AND AZIMUTH

A – B

Azimuths Bearings

00° 00’ 00’’ N 00° 00’ 00’’

B – C

Azimuths Bearings

180° 00’ 00’’ – 92° 40’ 25’’ N 87° 19’ 35’’ W

= 87° 19’ 35’’

C – D

Azimuths Bearings

92° 40’ 25’’ + 86° 47’ 05’’ S 00° 32’ 30’’ W

= 179° 27’ 30’’

180° 00’ 00’’ – 179° 27’ 30’’

= 00° 32’ 30’’

D – A

Azimuths Bearings

93° 47’ 25’’ + 00° 32’ 30’’ S 85° 40’ 05’’E

= 94° 19’ 55’’

180° 00’ 00’’ – 94° 16’ 15’’

= 85° 40’ 05’’


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4.4 COMPUTE COURSE LATITUDE AND DEPARTURE

Cos β Sin β L cos β L sin β

Station Bearing, β Length, L Cosine Sine Latitude Departure

A N 00° 00’ 00’’ 48.8626 1.0000 0.0000 + 48.8626 + 0.0000

B N 87° 19’ 35’’ W 29.3505 0.0466 0.9989 + 1.3691 - 29.3186

C S 00° 32’ 30’’ W 47.9427 0.9999 0.0095 - 47.9406 - 0.4532

D S 85° 40’ 05’’ E 29.8854 0.0755 0.9971 - 2.2574 + 29.8000

A

Total Perimeter (P) = 156.0412 Sum of

Latitude

∑∆y

= 0.0337

Sum of

Departure

∑∆x

= 0.0282


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4.5 DETERMINE THE ERROR OF CLOSURE

Error in Departure

A ∑∆x = 0.0282m

Error in Latitude

Ec ∑∆y = 0.0337m

Total Error

= 0.0439m

A’

Accuracy = 1 ; (P/Ec)

For average land surveying an accuracy of about 1:3000 is typical

Ec = [ (sum of latitude)2 + (sum of departure)2 ] 1/2

= [ (0.0337)2 + (0.0282)2 ] 1/2

= 0.0439m

P = 156.0263m

Accuracy = 1 : (156.0412/0.0439)

= 1 : 3554

Therefore, the traversing is acceptable.


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4.6 ADJUST COURSE LATITUDE AND DEPARTURE

The Compass Rule

Correction = - [ ∑∆y ] / P x L or – [ ∑∆x ] / P x L

Where,

∑∆y and ∑∆x = The error in latitude and departure

P = Total length of perimeter of the traverse

L = Length of a particular course

Station Unadjusted Corrections Adjusted

Latitude Departure Latitude Departure Latitude Departure

A + 48.8626 + 0.0000 - 0.0106 - 0.0088 + 48.8520 - 0.0088

B + 1.3691 - 29.3186 - 0.0063 - 0.0053 + 1.3628 - 29.3239

C - 47.9406 - 0.4532 - 0.0104 - 0.0087 - 47.9510 - 0.4619

D - 2.2574 + 29.8000 - 0.0064 - 0.0054 - 2.2638 + 29.7946

Total + 0.0337 + 0.0282 - 0.0337 -0.0282 0.00 0.00

Check Check


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5.0 DISCUSSION

From this fieldwork, we learnt to conduct a traverse survey by using a theodolite and

several formulas that we learnt during traversing class. Throughout this survey, we can be able to

applied the technique and knowledge thought by our lecturer, Mr. Chai.

From this survey, we know that point A, B, C and D are laid out on the site respectively.

The theodolite will be placed on point A which is our starting point and started to conduct our

survey. The angles that we get from the theodolite must be read from left to the right in order to

obtain a more accurate reading.

The zero angle will be set on point A as well and turned the theodolite to point D and

measure to get the stadia reading as well as the horizontal and vertical angles. After we get the all

the readings and the angles from one point, we switch the theodolite to another point and repeat

the same procedure again to get another point of readings.

What we found out that was really hard for us is we couldn’t get the spirit bubble into the

black circle. But after Mr. Chai had taught us, finally we can measure ourselves very fast and

accurately.

At the end of the process, the total angles must be 360°. However, in our report from the

table of the field data, the total angle was 357° 57’ 00’’. Thus, we knew that there was a

misclosure error occurred as there is a difference of 3’ 00’’. Means in every angle we measured,

there is a 45’’ of error. Therefore, we used the trigonometry traversing calculation technique to

solve it.

Lastly, at the end, we found that the latitude and departure also have a minor error of

0.0337 (Latitude) and 0.0282 (Departure). We solved it by using the compass rule. After compile

everything, the report is finally done.


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6.0 CONCLUSION

In conclusion, this is our second fieldwork which is traversing. In this fieldwork, we were

required to carry out a closed loop traverse survey that is located at the car park. A special

characteristic of a closed loop traverse is it starts and ends at the same point, forming a closed

geometric figure called a polygon. My fellow group mates and I conduct the survey together at

the car park. Two of them is holding the leveling staff, one of a group mate is recording down the

data while one of the group member is taking the readings for the traverse survey.

As we taught in class that the horizontal reading must be taken twice which is the first

reading is taken, then turn back again to take the second reading. We also did recorded the top

stadia, middle stadia and bottom stadia readings to calculate the length of the perimeter of the

traverse since we didn’t have a measuring tape.

The angles are usually obtained through the usage of equipment provided by our lecturer.

However, we were unable to obtain the exact reading of 360°, therefore, some adjustment was

made in order to achieve 360° in our traverse survey completely.

Although the formula was really hard for us to understand and apply compare to leveling,

but we try hard to learning with a spirit of not giving up. We really do likes site surveying

because we can actually feel that we are working together.

In a nutshell, we thanks our lecturer Mr. Chai for giving us an opportunities to learn and

hands on in leveling. We hope that next time we can have a chance to conduct a survey like this

again.

Traversing final-report

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