site survey fieldwork 2 traversing
TRANSCRIPT
SCHOOL OF ARCHITECTURE, BUILDING AND DESIGN
BACHELOR OF QUANTITY SURVEYING (HONOURS)
[QSB 60203] SITE SURVEYING
FIELDWORK 2
Traversing
NAME STUDENT ID
NG SHENG ZHE 0323830
SEW YUE LING 0327032
LIEU XUE QI 0327523
PHON KIT POI 0328435
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CONTENTS
CONTENT PAGE NUMBER
Cover page 1
Contents 2
Objectives 3
Introduction to Traversing 4-5
Apparatus Used for Traversing 6-7
Field Data 8-10
Adjusted Data 11-18
Summary 19
References 20
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Objectives
● To allow us to have a better understanding or knowledge about the process of using the
instrument (Theodolite) rather than learning from a video in class.
● To enable us to have the experience in using theodolite such as setting up,
collaborating, calculating and recording data.
● To allow us to have the teamwork while carrying out the fieldwork.
● To apply the theories that had learnt in class.
● To learn how to analyse the data collected.
● To enable us to have a basic knowledge on how to set up the points.
● To determine the error of misclosure in order whether is it acceptable or not in the
traversing calculation.
● To enable us to know the precautions should be taken while using Theodolite.
● To allow us to experience and expose to the actual working environment in site such as
working under the hot weather.
● To allow us to understand how to distribute different types of error from the data
collected on field.
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Introduction to TraversingTraversing is a method of survey and establish and a method to carry out a survey plan. From
the framework, the direction and length of the survey line must have a few of connected survey
lines because it is provide help for the angle measure instrument. When the connected line
formed a loop is called closed traverse, if the connected lines that did not formed a loop called
open traverse.
Two Types of Traverse 1) Closed Traverse
2) Open Traverse
1) Closed Traverse Closed traverses are used extensively in control, construction, property, and topographic
surveys. The loop traverse starts and ends at the same points. To check a validity and accuracy
of field measurements can use closed Traverses methods.
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2) Open Traverse A traverse whose end point is different from the starting point or is at an unknown position.
Normally, Open Traverse is apply on underground surveys. In addition, repeated observation is
required to minimize error.
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Apparatus Used for Traversing
Theodolite
A theodolite is an instrument for measuring angles in the horizontal and vertical planes.
Theodolites are used mainly for surveying applications, and have been adapted for specialized
purposes in fields like meteorology and rocket launch technology.
Tripod
A surveyor's tripod is a gadget used to support any one of a number of surveying instruments,
such as theodolites, total stations, levels or transits. The surveyor will adjust on the legs'
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platforms to securely anchor the legs in soil or drive the feet to a low position on uneven, pock-
marked pavement.
Plumb Bob
A plumb bob is a weight, at the bottom has a pointed tip that suspended from a string and used
as a vertical reference line.
Barcode Level Rod for Site Survey
It is made by wood or steel. It is used to determine the height of different points.
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Field Data
Station Field Angles
A 89°06’00”
B 89°27’40”
C 89°05’40”
D 90°59’40”
SUM= 358°39’00”
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D = K x s x cos²(θ) + C x cos (θ)
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 =
additive factor given by the manufacturer of the theodolite, (normally = 0)
Distance A-B = 100 x (1.493-1.324) x cos²((90°−90 °15' 00 )+(270° - 269° 43 ' 20 )
2) + ( 0 x
cos((90 °−90 °15' 00 )+(270° - 269° 43 ' 20 )
2) )
= 100 x 0.169 x cos²(0°00’50”) + 0
= 16.90
Distance B-A = 100 x (1.492-1.324) x cos²((90°−89 °17' 00 )+(270° - 270° 45 ' 00 )
2) + ( 0 x
cos((90 °−89 °17' 00 )+(270° - 270° 45 ' 00 )
2) )
= 100 x 0.168 x cos²(-0°01’00”) + 0
= 16.80
Average distance = (16.90 + 16.80)/2
= 16.85
Distance B-C = 100 x (1.560-1.269) x cos²((90 °−89 °54 ’ 40”) + (270°−270°04’40”)
2) + ( 0 x
cos((90 °−89 °54 ’ 40”) + (270°−270°04’40”)
2) )
= 100 x 0.291 x cos²(0°00’20”) + 0
= 29.10
Distance C-B = 100 x (1.555-1.265) x cos²((90 °−89 ° 41' 40 )+(270 ° - 270 °17 ' 00 )
2) + ( 0 x
cos((90 °−89 ° 41' 40 )+(270 ° - 270 °17 ' 00 )
2) )
= 100 x 0.290 x cos²(0°00’40”) + 0
= 29.00
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Average distance = (29.10 + 29.00)/2
= 29.05
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Distance C-D = 100 x (1.492-1.327) x cos²((90 °−89 °15' 00 )+(270 ° - 270 ° 45 ' 00 )
2) + ( 0 x
cos((90 °−89 °15' 00 )+(270 ° - 270 ° 45 ' 00 )
2) )
= 100 x 0.165 x cos²(0°) + 0
= 16.50
Distance D-C = 100 x (1.494-1.330) x cos²((90 °−89 °56' 20 )+(270 ° - 270 ° 02' 40 )
2) + ( 0 x
cos((90 °−89 °56' 20 )+(270 ° - 270 ° 02' 40 )
2) )
= 100 x 0.164 x cos²(0°00’30”) + 0
= 16.40
Average distance = (16.50+16.40)/2
= 16.45
Distance D-A = 100 x (1.545-1.256) x cos²((90 °−89 °39 ' 20 )+(270 ° - 270 ° 21' 00 )
2) + ( 0 x
cos((90 °−89 °39 ' 20 )+(270 ° - 270 ° 21' 00 )
2) )
= 100 x 0.289 x cos²(-0°00’10”) + 0
= 28.90
Distance A-D = 100 x (1.555 - 1.267) x cos²((90 °−90 °02' 20 )+(270 ° - 269 ° 59' 00 )
2) + ( 0 x
cos((90 °−90 °02' 20 )+(270 ° - 269 ° 59' 00 )
2) )
= 100 x 0.288 x cos²(-0°00’40”) + 0
= 28.80
Average distance = (28.90 + 28.80)/2
= 28.85
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Angular Error & Angle AdjustmentsAs known the sum of the interior angles in only loop traverse is equal to (n-2)(180°)for
geometric consistency,therefore
(4-2)(180° ¿= 2(180° ¿= 360
Total angular error = 360°00’00” - 358°39’00”
= 1°21’00”
Error per angle = 1°21’00”/4
= 0°20’15”
Station Field Angles Corrections Adjusted Angles
A 89° 06 ' 00 +0°20’15” 89°26’15”
B 89°27’40” +0°20’15” 89°47’55”
C 89°05’40” +0°20’15” 89°25’55”
D 90° 59' 40 +0°20’15” 91°19’55”
SUM= 358°39’00” 360°00’00”
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Computation for Course Azimuths
Station Adjusted Angles Course Azimuths Course Bearing
A-B 89°26’15” 89° 26 ' 15 N 89° 26 ' 15 E
B-C 89°47’55”89° 26 ' 15 +89°47’55”+180°=359°14’10”
N 0°45’50” W
C-D 89°25’55”359°14’10”+89°25’55”-180°=268°40’05”
S 88°40’05” W
D-A 91°19’55”268°40’05”+91°19’55”-180°=180°00’00”
S 0°00’00” E
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Computation for Latitude and Departure
Cos B Sin B L Cos B L Sin BStatio
n Bearing,B Length,L Cosine Sine Latitude Departure
A
N 89°26’15”E 16.85 0.0098 0.9999 +0.1651 +16.8483
B
N 0°45’50”W 29.05 0.9999 -0.0133 +29.0471 -0.3864
C
S 88°40’05”W 16.45 -0.0232 -0.9997 -0.3816 -16.4451
D
S 0°00’00” 28.85 -1.0000 0.0000 -28.8500 0.0000
A Perimeter(P)=91.20 Sum of latitudes=∑ΔY=-0.0194 Sum of departures=∑ΔX=+0.0168
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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
Accuracy = 1: (P/Ec)
Therefore, the accuracy = 1: (91.20/0.0257)
= 1: 3548.6
= 1: 3549
For average land surveying, an accuracy of about 1:300 is typical.
Thus, the accuracy of field is acceptable.
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A
A’
Error in departure∑∆ x=+0.0168m
Error in latitude∑∆ y=−0.0194m
Ec, Total Error91.20 m
Adjusted Course Latitude & Departure
The compass rule:
Correction = -[y]P x L or - [x]P x L
Latitude CorrectionThe correction to the latitude:
Course A-B is
[-0.0194÷ 91.20] x 16.85 = -0.00358
Course B-C is
[-0.0194÷ 91.20] x 29.05 = -0.00618
Course C-D is
[-0.0194÷ 91.20] x 16.45 = -0.00350
Course D-A is
[-0.0194÷ 91.20] x 28.85 = -0.00614
Departure CorrectionThe correction to the departure:
Course A-B is
[0.0168÷ 91.20] x 16.85 = 0.00310
Course B-C is
[0.0168÷ 91.20] x 29.05 =0.00535
Course C-D is
[0.0168÷ 91.20] x 16.45 = 0.00303
Course D-A is
[0.0168÷ 91.20] x 28.85 =0.00531
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Adjust Course Latitudes and Departures
Unadjusted Corrections Adjusted
Station Latitude Departure Latitude Departure Latitude Departure
A
+ 0.1651 + 16.8483 0.0036 - 0.0031 + 0.1687 + 16.8452
B
+ 29.0471 - 0.3864 0.0062 -0.0054 + 29.0533 -0.3918
C
-0.3816 -16.4451 0.0035 -0.0030 -0.3781 -16.4481
D
-28.8500 0.0000 0.0061 -0.0053 -28.8439 -0.0053
A
Check -0.0194 + 0.0168 0.0194 -0.0168 0.00 0.00
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Computation of Station Coordinates
Assume that the coordinates of A is (100.000, 100.000)
Station N Coordinate* Latitude E Coordinate* Departure
A 100.000 (Assumed) 100.000 (Assumed)
+ 0.1687 + 16.8452
B 100.1687 116.8452
+ 29.0533 -0.3918
C 129.2220 116.4534
-0.3718 -16.4481
D 128.8439 100.0053
-28.8439 -0.0053
A 100.000 (Checked) 100.000 (Checked)
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00
N 128.84E 100.00
N 129.22E 116.45
N 100.00E 100.00
N 100.17E 116.85
z
D
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100
110
120
130
z120110100
A B
C
NORTH
EAST
SummaryIn this second fieldwork, we are required to do a closed loop traverse by using a theodolite at
the carpark in Taylor’s University Lakeside Campus. The first thing we did is to set up the
instrument and to mark four points for station which are station A, B, C and D. Before we took
the measurement, we levelled the theodolite.
First of all, we know that the point A, B, C and D are laid out on the site respectively. The
theodolite is placed at station A which is our starting point and adjust it until it is in horizontal
level. Besides, the other stations (A, B, C, D) must be stated on the site to form a loop traverse
by using liquid ink. After that, we used theodolite to measure the angles of four stations as our
field data. 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. The angles of the theodolite
must be read from left to right in order to obtain a more accurate reading.
In order to obtain the angles form each point, the process is repeated at each of the points on
the site. During the measurement, the vertical and horizontal angles will be shown on the digital
readout panel. Everything went well but the readings were imperfect so we had to do the
distribution error.
Our total angular for the loop traverse is 358°〖39〗^' 00'' and the total error angular is about
1°〖21〗^' 00''. Therefore, it has 0°20'15'' error in angle for each angle.
Our error in latitude is -0.0194 and our error in departure is +0.0168. Thus, the total error is
0.0257. Using the following formula, we calculated the accuracy of our traverse survey:
Accuracy = 1: (P/EC), 1: [Perimeter/ Error Closure]
We obtained an accuracy of 1:3549. For average land surveying an accuracy of 1:3000 is
typical. Therefore, our traverse survey is acceptable.
In conclusion, we faced a lot of obstacles during the fieldwork. One of obstacles is we have to
ensure that the spirit bubbles have to be exactly at the centre point. We took a lot of time to set
up the theodolite at the first time because we have to make sure the spirit level is always in
middle in every position. Although the formula was really hard for us to apply compare to
levelling, but we try hard to learning with a spirit of not giving up.
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Referenceshttp://surfcivil.blogspot.my/2010/05/traverse-surveying.html
http://www.state.nj.us/transportation/eng/documents/survey/Chapter5.shtm
Photo of group members:
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Phon Kit Poi Ng Sheng Zhe
Sew Yue Ling Lieu Xue Qi