site surveying report 2
TRANSCRIPT
SCHOOL OF ARCHITECTURE, BUILDING AND DESIGN
BACHELOR OF QUANTITY SURVEYING (HONOURS)
QSB60103103946-M - SITE SURVEYING
Fieldwork Report 2 TITLE: Traverse
GROUP MEMBERS: ID1. Yeo Dor Een 0316224
2. Welson Lum Wei Jiunn 0319514
3. Yap Jia En 0319550
4. Yong Sing Yew 0318766
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Table of Content
Content PagesCover Page 1
Table of Content 2Introduction to Traverse 3-5
Introduction of Apparatus 6-7Data and Results 8-14
Reference 15
Introduction to TraversingWhat is Traversing?
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Traversing is a survey which involves a connected sequences of line whose
length and direction are measured. It involves placing survey points along a
line or path of travel, and then using back the previously surveyed points as a
base for observing next point. It is a common method of control surveys
performed by surveyors in the field.
Objectives
The objectives of this field work 2 (Traverse) is to:
a) To give a proper understanding of traversing
b) To understand the method used in traversing
There are two type of traverse which are:
(a) Open Traverse:
An open traverse start on a known point and finished on an unknown
point. This lack of geometric closure means that there is no geometric
verification possible with respect to the actual positioning of the traverse
stations. An open traverse is commonly used for exploratory purpose such as
mine surveying. It should generally not be used in civil engineering works
unless situation needed.
Figure 1: Example of Open Traverse
(b) Closed traverse:
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A closed traverse is one enclosing a defined area and having a
common point for its beginning to end. It starts and ends at the same point,
forming a closed geometric figure called a polygon. This type of traverse was
the type that we doing for our field work.
Figure 2: Example of Closed Traverse
Selection of Station
i. The select station positions should be as close as possible to the
objects to be located.
ii. The selected station should be mark out clearly by anything which is
suitable.
iii. The chosen point should not be blocked by anything so that we can get
the reading from the other point.
iv. Too many points will increase the time and cost of the survey. However
too less points may provide a not sufficient control for the project.
Bearings
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A bearings are never greater than 90 °. It is referenced from north or south and the angle to the east or west from the north-south meridian.
Azimuths
An azimuths range from 0 to 360°. It is an angle measured clockwise from any reference meridian.
Figure 3: Bearings and Azimuths
Acceptable Misclosure
Commonly for land surveying, an accuracy of about 1:3000 is typical. An accuracy of at least 1:5000 would be required for third-order control traverse surveys. The acceptable misclosure can be measured by:
Accuracy = 1: (P/EC)
P= Perimeter of the Entire Traverse
Ec= The Total Error
Introduction of Apparatus
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Theodolite
A theodolite is a surveying instrument with a rotating telescope for measuring
horizontal and vertical angles. Theodolite are mainly used for surveying and
have been adapted for specialized purposes in fields
like meteorology and rocket launch technology. When the telescope of the
theodolite is pointed at a target object, the angle of each of these axes can be
measured with great precision, typically to seconds of arc.
Figure 1: Theodolite
Tripod
A surveyor’s tripod is an instrument used to support any surveying instrument
for example theodolite and others. The head of the tripod supports and lock
the instrument while the feet are spiked to anchor the tripod to the ground. It
provides stability against downward forces and horizontal forces and
movements about horizontal axes. We need to set up the theodolite on the
tripod.
Figure 2: Tripod
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Leveling Rod
A levelling rod also called levelling staff. It is a graduated wooden or
aluminium rod, used with a levelling instrument to determine the different in
height between points or heights or points above a datum surface. The
levelling rod we used in fieldwork was aluminium rod. We get the height of the
theodolite after set up everything and mark the height of it on the levelling rod
with rubber band. In this fieldwork we used 2 levelling rod.
Figure 3: Levelling Rod
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Data and ResultsField Data
Point
Stadia Reading 1:
Stadia Reading 2: Horizontal Angle:
A T - 148.5 T - 157 168°44’40” /2M - 143.0 M - 143 =84°22’20”B - 137.5 B - 130
V - 89°25’00” V - 9
0°01’20”
B T - 160 T - 151.5 144°44’40” /2M - 147 M - 147.0 =72°22’20”B - 133 B - 141.5
V - 89°56’00” V - 8
9°42’00”
C T - 147.5 T - 154.0 224°34’20” /2
M - 142.5 M - 142.5 =112°17’10”
B - 137.5 B - 131.0
V - 90°14’20” V - 8
9°47’40”
D T - 153.5 T - 147.5 181°51’40” /2M - 142.0 M - 142.0 =90°55’50”B - 130.5 B - 136.0
V - 90°11’40” V - 9
0°32’00”
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Compute The Angular Error & Adjust The AnglesSum of interior angles :
(n-2) x 180 °= (4-2) x 180°
= 360°
Total angular error = 360°- 359°57’40”= 0°2’20”
Therefore, error per angle = 4 = 0°0’35”
Station Field Angles Correction Adjusted angles
A-B 84°22’20’ 0°0’35” 84°22’55’’
B-C 72°22’20’’ 0°0’35’’ 72°22’55’’
C-D 112°17’10’’ 0°0’35’ 112°17’45’
D-A 90°55’50’’ 0°0’35’’ 90°56’25’’
Sum 359°57’40’’ 0°2’20” 360°00’00’’
DistanceD= K s sin2(θ)
Distance A-B = 100 (157-130) sin2 (90°01’20”) = 27.00m
Distance B-C = 100 (151.5-141.5) sin2 (89°42’00”) = 10.00m
Distance C-D = 100 (154-131) sin2 (89°47’40”) = 23.00m
Distance D-A = 100 (147.5-136.0) sin2 (90°32’00”) = 11.50m
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B
10m
C 72°22’55”
112°17’45”
23m 27m
90°56’25” 84°22’55’’
D A
11.5m
(Not to scale)
Azimuth
Station D - A : 90°56’25’’
Station A - B : 270° + 84°22’55” + 0°56’25” = 355°19’20”
Station B - C: 180° + (72°22’55”- 4°40’40”) = 247°42’15”
Station C - D: 180°
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Computations For Latitude and Departure
Figure 1.1: Algebraic sign convention for latitude and departure
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Computations For Latitude and Departure
Length
Cos Sin Latitude Departure
Station
L(m) Bearing Cos θ
Sin θ L Cos θ L Sin θ
A-B 27 N 4°40’40” W 0.997 0.082 +26.919 -2.214
B-C 10 S 67°42’15’’ W 0.379 0.925 -3.790 -9.250
C-D 23 S 0° 00’00” E/W
1.000 0.000 -23.000 0.000
D-A 11.5 S 89°03’35’’ E 0.016 1.000 -0.184 +11.500
Total 71.5 -0.055 0.036
Accuracy = 1 : (P/Ec)
P = Total Length
Ec = [ (sum of latitude)2 + (sum of departure)2 ]1/2
Accuracy = 1 : (71.5 / 0.0657) = 1 : 1088.
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Adjusted Course Latitudes and Departures
The Compass Rule
Correction = – [ ∑∆y ] / P x L or – [ ∑∆x ] / P x L
Where,
∑∆y and ∑∆x = The total error in latitude and departure
P = Total length of perimeter of the traverse
L = Length of a particular course
Unadjusted Correction Adjusted
Station
Latitude Departure
Latitude Departure Latitude
Departure
A
+26.919 -2.214 0.020 -0.014 26.939 -2.228
B
-3.790 -9.250 0.008 -0.005 -3.782 -9.255
C
-23.000 0.000 0.018 -0.012 -22.982 -0.012
D
-0.184 +11.500 0.009 -0.005 -0.175 11.495
A
SUM -0.055 0.036 0.055 -0.036 0.000 0.000
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Computation of Station Coordinates
Station Adjusted Latitude
Adjusted Departure
N Coordinate Latitude (y-axis)
E Coordinates Departure(x-axis)
A 100.000 (Assumed)
100.000 (Assumed)
26.939 -2.228
B 126.939 97.772
-3.782 -9.255
C 123.157 88.517
-22.982 -0.012
D 100.175 88.505
-0.175 11.495
A 100.000 100.000
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Discussion
In this fieldwork, we were required to carry out a closed loop
traverse survey. The location was at the car park as well. 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 used for this fieldwork is theodolite,
tripod and plumb bob. Before starting the fieldwork, we roughly marked
four points of stations which are station A, B, C and D by using masking
tape.
After set up of theodolite, we used it to measure the angles of four
stations (A, B, C and D) as our field data. The theodolite is placed at
point A, and the horizontal angle of point A is achieved by reading the
theodolite through point D to B. The angles of the theodolite must be read
from left to right in order to obtain an accurate reading. This process is
repeated at each of the points. Horizontal and vertical angles are
recorded. We also have to record the top, middle and bottom stadia
readings. After the fieldwork is done, calculation of data is carried out to
obtain results.
Our group has faced some problems in this project. We carried out
two attempts in this fieldwork since the first attempt has failed to get an
accurate result. With the help from our lecturer in the second attempt, we
were able to solve the problems and get the result efficiently.
Furthermore, we also learnt that group work is very important in
the fieldwork. The survey could not be done smoothly by the absence of
any one of our group members. Participation of every group members is
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much appreciated that we were able to finish the fieldwork and obtain the
result on time.
Last but not least, thank to our lecturer, Mr. Chai who has taught us
on how to use a theodolite. This fieldwork has been completed
successfully by us with the patience and guidance from Mr. Chai.
Overall, this fieldwork has taught us a lot of hands-on knowledge about
the surveying.
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Reference
1. http://www.hbp.usm.my/hilmy/traverse.pdf
2. http://www.globalsecurity.org/military/library/
policy/army/fm/5-233/ch7.pdf
3. http://ecology.lifescience.ntu.edu.tw/
course_932_ecology/Lab/TraverseMeasurement.pdf
4. https://engineering.purdue.edu/~asm215/topics/
bearings.html
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