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TAYLOR’S UNIVERSITY | SABD | BQS
SCHOOL OF ARCHITECTURE, BUILDING AND DESIGN
BACHELOR OF QUANTITY SURVEYING (HONOURS)
QSB 60103 - SITE SURVEYING
FIELDWORK REPORT 2
TRAVERSING
NAME STUDENT ID. MARKS LEE KAILYN 0320273
LIEW POH KA 0320424
DEONG KHAI KEAT 0320055
HUSNI NAIM BIN MOHD ZUHALI 0326126
TABLE OF CONTENT
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CONTENT PAGES NO.
COVER PAGE 1
TABLE OF CONTENT 2
INTRODUCTION OF TRAVERSING 3 - 5
APPARATUS USED 6 - 8
OBJECTIVE 9
FIELD DATA 10 - 11
ADJUSTED FIELD DATA 12 - 15
ADJUSTED COURSE LATITUDE & DEPARTURE
16 - 17
COMPUTATION OF STATION COORDINATES & GRAPH
18 - 19
DISCUSSION 20 - 21
REFERENCES 22
2
INTRODUCTION OF TRAVERSING Traverse Surveying is a popular method of surveying. This article includes
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definition of traverse surveying along with its classification, errors in traversing, checks, the completed method of traversing and plotting of traverse survey. A traverse is a series of connected lines whose lengths and directions of the survey lines are measured with the help of an angle measuring instrument and a tape or chain respectively. The lines connect a series of connected points called traverse stations. The angles and distances between points are measured using different types of measuring equipment. The angles are often measured using total station or theodolite while the distances are often measured using steel tape, total station or electronic distance measurement instrument. Traversing is used in control survey to determine a network of horizontal reference points called control points.
There are 2 type of Traversing
a) Open Traverse
An open traverse is a series of connected lines that do not intersect or form a loop. An open traverse is one which does not close on the point of the beginning. It ends at a station whose relative position is not known before. It is normally not used as there is no check on fieldwork or starting data.
3b) Closed Traverse
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A closed traverse is a series of connected lines whose lengths and bearings are measured off these lines (or sides), which enclose an area. A closed traverse can be used to show the shape of the perimeter of a fire or burn area. If you were to pace continuously along the sides of a closed traverse, the finishing point would be the same as the starting location.
There are two types of closed traverse:
i) Loop traverse:It starts and ends at the same point, forming a loop or a polygon.
ii) Connecting traverse:It looks similar to open traverse, however it starts and ends at points of known position at every end of traverse.
Bearing and AzimuthThe direction or angle of the lines can be described by its azimuth or bearing
AzimuthAn azimuth is the direction measured in degrees clockwise from north on an azimuth circle. An azimuth circle consists of 360 degrees. Ninety degrees corresponds to east, 180 degrees is south, 270 degrees is west, and 360 degrees and 0 degrees mark north.
4Bearing
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A bearing provides a direction given as the primary compass direction (north or south), degree of angle, and an east or west designation. A bearing describes a line as heading north or south, and deflected some number of degrees toward the east or west. A bearing, therefore, will always have an angle less than 90°. It can belong to one of four quadrants:
Compass Rule and Transit RuleThere are two ways of adjusting the course latitude and departures during traversing. This is to do correction to the data to enable accurate result.
The Compass rule is based on the assumption that all lengths we measured with equal care and all angles taken with approximately the same precision.
Transit rule is the method of adjusting a traverse by the transit rule similar to the method using the compass rule. The main difference is that with the transit rule the latitude and departure corrections depend on the length of the latitude and departure of the course respectively instead of both depending on the length of the course.
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5
APPARATUS USEDa) Theodolite
A theodolite consists of a telescope mounted on a base. The telescope has a sight on the top of it that is used to align the target. The instrument has a focusing knob that is used to make the object clear. A theodolite works by combining optical plummets (or plumb bobs), a spirit (bubble level), and graduated circles to find vertical and horizontal angles in surveying. The telescope contains an eyepiece that the user looks through to find the target being sighted. The theodolite's base is threaded for easy mounting on a tripod.
b) Adjustable leg-tripod
A sturdy tripod in good condition is essential for obtaining accurate measurement. They provide a level base to easily mount and securely hold your instrument. The legs of tripod are adjustable and are made of wood, fiberglass or aluminium are adjustable for use in different types of surveying equipment.
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6
c) Levelling Rod
Levelling rods can be one piece, but many are sectional and can be shortened for storage and transport or lengthened for use. Aluminum rods may be shortened by telescoping sections inside each other. It also a graduated rod used in measuring the vertical distance between a point on the ground and the line of sight of a surveyor's level.
d) Optical Plummet /Tribrach
In surveying, a device used in place of a plumb bob to center transits and theodolites over a given point, preferred for its steadiness in strong winds.
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7
e) Spirit Bubble
A spirit level, bubble level or simply a level is an instrument designed to indicate whether a surface is horizontal (level) or vertical (plumb). It is used in different types of instrument by the surveyor.
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8
OBJECTIVE
To enhance the student knowledge learn in class about traversing procedure and apply it in the field work.
To learn the principles of running a closed field traverse.
To let students have experience in setting up and working with the instruments such as theodolite.
To enable us to learn how to analyze data collected.
To increase team working skills among the group members.
To allow us to have the ability to undertake site measurements and calculations.
To determine the error of closure and compute the accuracy of the work.
To determine the area encompassed within a boundary.
To establish the positions of boundary lines.
To determine and adjust the course of latitude and departures.
To be familiar with the various types and methods of traversing surveying for detailing.
To determine the adjusted independent coordinates of the traverse stations so that they can be plotted at the graph.
To enable us to know the precautions should be taken while using theodolite.
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9
FIELD DATA
Station A B C D
Sighted Station D B A C B D C A
StadiaReading
Top 1.600 1.450 1.538 1.690 1.725 1.570 1.650 1.600
Middle 1.382 1.382 1.470 1.470 1.505 1.505 1.580 1.580
Bottom 1.163 1.315 1.403 1.253 1.285 1.435 1.515 1.165
Difference between Top and
Bottom0.437 0.135 0.135 0.437 0.440 0.135 0.135 0.435
Vertical Angle
90˚06’00’
’
90˚08’20’
’
89˚50’20’
’
90˚04’20’
’
89˚55’50’
’
89˚54’40’’
90˚04’20’
89˚53’40’’
269˚54’00’
’
259˚51’20’
’
270˚09’40’
’
269˚55’20’
’
270˚05’00’
’
270˚04’20’’
268˚55’40’
270˚07’40’’
Average Vertical Angle
90˚06’00’
’
90˚08’30’
’
89˚50’20’
’
90˚04’30’
’
89˚55’25’
’
89˚55’10’’
90˚34’20’
89˚53’00’’
Average of Elevation/
Depression
-06’00’
’
-08’30’
’
09’40’’
-04’30’
’
04’35’’ 04’50’’ -
34’20’ 07’00’’
Interior Angle85˚18’30’’ 94˚12’45’’ 84˚16’14’’ 96˚14’38’’
85˚19’30’’ 94˚12’11’’ 84˚15’18’’ 96˚15’34’’
Average Interior Angle 85° 19’ 00” 94° 12’ 28” 84° 15’ 46” 96° 15’ 06”
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10
FIELD DATA
Station Field Angles
A 85° 19’ 00”B 94° 12’ 28”
C 84° 15’ 46”D 96° 15’ 06”
Total 360° 02’ 20”
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(Not to scale)
B
C
A
D84˚15’46’’
94˚12’28’’
95˚15’06’’
85˚19’00’’
Raw Data Unadjusted
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11 ANGULAR ERROR AND ANGLE ADJUSTMENTS
Total Angular Error = 360°02’20” - 360° = 02’ 20”
Therefore, error per angle = 0° 02’ 20” ÷ 4 = 0°0’35” per angle
Station Field Angles Correction Adjusted Angles
A 85° 19’ 00” 0° 0’ 35” 85° 18’ 25”
B 94° 12’ 28” 0° 0’ 35” 94° 11’ 53”
C 84° 15’ 46” 0° 0’ 35” 84° 15’ 11”
D 96° 15’ 06” 0° 0’ 35” 96° 14’ 31”
Total 360° 02’ 20” 360° 0’ 0”
SITE SURVEYING | QSB 60103(Not to scale)
B
C
A
D84˚15’11’’
94˚11’53’’
96˚14’31’’
85˚18’25’’
Raw Data Adjusted
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12 CALCULATION OF HORIZONTAL DISTANCE
D = K × s × cos²(θ) + C × cos(θ)
Station Distance Average Distance
A-DD = 100 × 0.437 × cos²(-6’00’’) + 0 × cos(-
6’00’’) =43.6999 43.6999+43.4998
2=¿43.5999
D-AD = 100 × 0.435 × cos²(7’00’’) + 0 × cos(7’00’’)
=43.4998
B-AD = 100 × 0.135 × cos²(9’40’’) + 0 × cos(9’40’’)
=13.4999 13.4999+13.4999
2=¿ 13.4999
A-BD = 100 × 0.135 × cos²(-8’30’’) + 0 × cos(-
8’30’’) =13.4999
C-BD = 100 × 0.440 × cos²(4’35’’) + 0 × cos(4’35’’)
=43.9999
43.9999+43.69992
=¿
43.8499B-CD = 100 × 0.437 × cos²(-4’30’’) + 0 × cos(-
4’30’’) =43.6999
D-CD = 100 × 0.135 × cos²(-34’20’’) + 0 × cos(-
34’20’’) =13.4987 13.3987+13.5000
2=¿13.4994
C-DD = 100 × 0.135 × cos²(4’50’’) + 0 × cos(4’50’’)
=13.5000
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13 COMPUTING COURSE AZIMUTHS AND BEARINGS
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85˚18’25’’
D
BA
84˚15’11’’
00˚29’42’’
?
C
B
D
Azimuths Bearings
85˚18’25’’ N 85˚18’25” E
85˚18’25’’ + 180˚00’00’’
+ 94˚11’53’’359˚30’18’’
359˚30’18’’
180˚00’00’’‒ 85˚18’25’’‒ 94˚11’53’’ 00˚29’42’’
N 00˚29’42’’ W
359˚30’18’’– 180˚00’00’’ 179˚30’18’’+ 84˚15’11’’ 263˚45’29’’
263˚45’29’’
84˚15’11’’‒ 00˚29’42’’ 83˚45’29’’
S 83˚45’29’’ W
263˚45’29’’‒ 180˚00’00’’ 83˚45’29’’+ 96˚14’31’’ 180˚00’00’’
180˚00’00’’
180˚00’00’’ ‒ 83˚45’29’’ ‒ 96˚14’31’’ 00˚00’00’’
S 00˚00’00’’ E
A - B
B - C
C - D
D - A
Line
85˚18’25’’
?
94˚11’53’’
C
BA
83˚45’29’’
96˚14’31’’
C
A
D
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14
Station Length Bearing Cosine,
Cos β
Sin e, Sin β
Latitude, L Cos β
Departure, L Sin β
A-B 13.4999 N 85°18’ 25” E 0.0818 0.9966 1.1043 13.4540
B-C 43.8499 N 0° 29’42” W 1.0000
0.0086
43.8499 -0.3771
C-D 13.4994 S 83°45’ 29”W 0.1087
0.9941
-1.467 -13.4198
D-A 43.5999 S 0°00’00” E 1.0000 0 -43.5999 0
Total 114.4491 -0.1127 -0.3429
Accuracy calculation:Accuracy = 1: (P/Ec) , typical 3000Ec = [(sum of latitude)² + (sum of departure)²]1/2
= [ (-0.1127)² + (-0.3429)² ] 1/2
= 0.3609
Calculation :
Accuracy = 1: (114.4491 /0.3609) = 1: 317
Error in departureA ∑Δx= - 0.3429
Error in latitude Ec ∑Δy = - 0.1127
Total Error 0.3609 ft A’
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Therefore, the traversing is not acceptable. 15 ADJUSTED COURSE LATITUDE AND DEPARTURE
The compass rule : Correction = - [∑Δy] ÷ P x L or - [∑Δx] ÷ P x L
LATITUDE CORRECTION
The correction to the latitude of course A-B is[-0.1127÷ 114.4491] x 13.4999 = -0.01329
The correction to the latitude of course B-C is[-0.1127÷ 114.4491] x 43.8499 = -0.04318
The correction to the latitude of course C-D is [-0.1127÷ 114.4491] x 13.4994 = -0.01329
The correction the latitude of course D-A is [-0.1127÷ 114.4491] x 43.5999 = -0.04293
DEPARTURE CORRECTION
The correction to the departure of course A-B is [-0.3429÷ 114.4491] x 13.4999 = -0.04045
The correction to the departure of course B-C is[-0.3429÷ 114.4491] x 43.8499 = -0.13138
The correction to the departure of course C-D is[-0.3429÷ 114.4491] x 13.4994 =-0.04045
The correction to the departure of course D-A is [-0.3429÷ 114.4491] x 43.5999 = -0.13063
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16
17
Station Unadjusted Correction Adjusted
Latitude Departure Latitude Departure Latitude Departure
A
B
C
D
+1.1043
+43.8499
-1.467
-43.5999
+13.4540
- 0.3771
-13.4198
0
0.0133
0.0432
0.0133
0.0429
0.0404
0.1314
0.0405
0.1306
+1.1176
+43.8931
-1.4537
-43.5570
+13.4944
-0.2457
-13.3793
+0.1306
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A
Check -0.1127 -0.3429 0.1127 0.3429 0.0000 0.0000
COMPUTE STATION COORDINATES
18
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Station N coordinate* Latitude E coordinate* Departure
A
B
C
D
A
1000.0000
+ 1.1176 1001.1176
+ 43.8931
1045.0107
- 1.4537 1043.5770
- 43.5570
1000.0000
1000.0000 + 13.4944 1013.4944
- 0.2457
1013.2487
- 13.3793
999.8694
+ 0.1306
1000.0000
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DISCUSSION This report is for our second field work. For this field work, each group is required to have 4 people to complete the field work. This field work is to do a traversing which is closed loop traverse. Closed loop traverse is a loop traverse starts and ends at the same point, forming a closed geometric figure called a polygon which is the boundary lines of a tract land. The equipment that we utilized requires theodolite, tripod and measuring rod. The main activity we have to conduct is to setup the measuring rod at different points and use the auto level machine to calculate the angle between the measuring rods. Before we start our field work, we are required to mark four points of stations which are station A, B, C and D. After that, we are required to setup the instrument. We have to level the theodolite before we took the measurement. There’s an air bubble inside the boundary of the circle is to ensure the theodolite is on the flat surface.
Next, we used the theodolite to measure the angles of the four stations as our field data. The theodolite will be placed on point A which is our starting point and started to conduct our survey. One person is assigned to hold measuring rod and required to stand at the point we fixed. One person is assigned to record down the data and the others are taking the readings for the traverse survey. The angles of the theodolite must be read from the left to the right to obtain an accurate reading. In the vision through the theodolite, we are able to receive 3 horizontal line act as marking which are top stadia, middle stadia and bottom stadia readings. This process is repeated at each of the point on the site. During measurement, the horizontal and vertical angles will be shown on the digital readout panel. We are able to get the length of the field work by subtracting the top and bottom.
The total angle must be 360°. Our total angular for loop traverse is 360°02’20” and the total angular error is about 0°02’20”. Thus, we had to adjust it. There is a 0°0’35” of error in every angle we measured. Besides, we are able to calculate the error by determining the bearing. Our error in latitude is -0.1127 while our error in departure is -0.3429. The total error is 0.3609. Before we adjust our readings we get, the accuracy should be at least 1:3000 is important to be calculated to ensure the error of closure and the accuracy are acceptable. However, after carry out the second attempts for this field work, we are still unable to obtain the accurate and acceptable result. The accuracy we calculated is 317 which are unacceptable. There are some possible errors that affecting the results which caused us unable to obtain accurate and acceptable result. There might be instrument errors while doing the field work such as 20
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non-adjustment plate bubble. This happens when the axis of plate bubble may not be perpendicular to vertical axis. When the plate level is centered, the vertical axis may not be truly vertical. If the horizontal circle would be inclined, the angle will be measured in an inclined plane. This would cause an error. Some of the instruments have long time never send to calibrate will also cause error to the reading when obtaining. Other than that, personal error may be the possible error. The centering may not be done perfectly due to carelessness. The leveling may not be done carefully according to usual procedure. If the clamp screws are not properly fixed, the instrument may slip easily. Therefore, error would be result when obtaining the reading. Besides personal error, natural errors will also affecting the result. Natural errors might come from high temperature environment and strong wind. Hot temperature can causes error due to irregular refraction and high wind can causes vibration in the instrument and this may lead to wrong readings while doing the field work. To adjust the error exist in the latitude and departure, we are required to use the formula of the compass rule. The compass rule:
Correction = - [∑Δy] ÷ P x L or - [∑Δx] ÷ P x L
After the field data are adjusted, we are required to compute stations coordinates using their coordinates at a graph with assuming the coordinates of station A is (1000.000, 1000.000).
Throughout this field work, it is a great experience for us to explore and to have a better understanding about the traversing. We are able to apply the technique and knowledge that we learnt during lecture class. By carry out this field work, we find out that the formula is much harder for us to understand compared to levelling. Our group has faced some problems during the field work. We carried out two attempts in this field work since the first attempt has failed to get the accurate result. However, after repeating this field work twice, we are still failed to get the accurate result. Furthermore, we have learnt the team work is very important in this field work. Through this field work, we are able to gain a lot hands on knowledge about the surveying. Thanks to our lecturer Mr. Chai for giving us the opportunity to learn and experience the hands on in levelling. We appreciate to have the opportunity to have a practical experience in site surveying.
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References
1) (Dictionary of Construction, n.d.)http://www.dictionaryofconstruction.com/definition/optical-plummet.html
2) (Ben Meadow’s, n.d.)https://www.benmeadows.com/refinfo/techfacts/techpdf/survey_equipment_1360.pdf
3) (Surveying & Measurement, n.d.)http://moodle.najah.edu/pluginfile.php/47169/mod_resource/content/0/Angles_Azimuths_Bearings.pdf
4) (Open & Closed Traverse, n.d.)http://cms.cerritos.edu/uploads/dmussaw/open%20and%20closed%20traverse.pdf
5) (Fire Fighter Math, n.d.)http://www.firefightermath.org/index.php?option=com_content&view=article&id=58&Itemid=72
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