Site Surveying Traversing

SCHOOL OF ARCHITECTURE, BUILDING AND

DESIGN

BACHELOR OF QUANTITY SURVEYING (HONOURS)

SITE SURVEYING [QSB 60103]

FIELD WORK 2 REPORT

TRAVERSING

DARREN TAN QUAN WEN 0322662

YEAP PHAY SHIAN 0322243

LEE XIN YING 0322432

MICHELLE TUNG MAN KAYE 0324175

LOH MUN TONG 0323680

LECTURER: MR. CHAI VOON CHIET

SUBMISSION DATE: 8th DECEMBER 2016

1

TABLE OF CONTENT

NO. TOPIC PAGE

1. INTRODUCTION TO TRAVERSING 3 – 4

2. OBJECTIVES 5

3. APPARATUS USED 6 - 7

4. FIELD DATA 1

4.1 Unadjusted Field Data

4.2 Average Field Data

4.3 Angular error and angle adjustment

4.4 Course Bearings & Azimuths

4.5 Course Latitudes & Departures

4.6 Adjusted Latitudes & Departures

4.7 Table and Graph of Station Coordinate

8 - 16

5. FIELD DATA 2








17 - 25

6. FIELD DATA 3








26 - 33

2

7. AUTO LEVEL DISTANCE 34

8. ADJUSTED FIELD DATA

8.1.0 Adjusted Field Data 1

8.1.1 Compass rule correction to latitude and departure

8.1.2 Computation of station coordination

8.1.3 Graph of Station Coordinate









35 - 43

9. DISCUSSION 44

3

INTRODUCTION TO TRAVERSING

A traverse survey involves a connected sequence of lines whose length and directions

are measured. It is perhaps the most common type of control survey performed by surveyors in

private practice or employed by local government agencies. Precise traverse surveys are much

more practical nowadays with the use of electronic distance measuring (EDM) devices.

Traversing is a type of survey in which a number of connected survey lines from the

framework and the directions and lengths of the survey lines are measured with the help of an

angle measuring instrument and a tape or chain respectively. The angles are measured using

theodolites, or total stations, whereas the distances can be measured using total stations, steel

tapes or electronic distance-measurement instruments (EDMs).

There are two types of traverse:

(1) Open traverse: When the lines from a circuit ends elsewhere

(2) Closed traverse: When the lines from a circuit which ends at the starting point

4

(1) Open traverse

An open traverse is a series of measured straight lines that do not intersect or form a loop. This

lack of geometric closure means that there is no geometric verification possible with respect to

the actual positioning of the traverse stations. In route surveys, open traverse station positioning

can be verified by computation from available tied-in field markers as shown on property plans,

or through the use of global positioning system (GPS) receivers.

(2) Closed traverse

A closed traverse is connected lines that start at a point and ends at the same point or at a point

whose relative position is known. The errors during measurement are minimized and adjusted to

get accurate data. Closed traverse is the primary method used in checking surveying field work.

There are two types of closed traverse:

(a) Loop traverse – A loop traverse starts and ends at the same point, forming a closed

geometric figure called a polygon.

(b) Connecting traverse – A connecting traverse looks like an open traverse, however

the only difference is it begins and ends at points (or lines) of

known position (and direction) at each end of the traverse.

5

OBJECTIVES

● To enhance a better understanding of the traverse process.

● To determine the area encompassed within a boundary.

● To determine the angular error and closing error of traverse conducted.

● To make necessary adjustments in obtaining an accurate data.

● To experience the life of being as a Quantity Surveyor and experience the actual

working environment.

● To help them to understand the correct way to read the reading on the theodolite

and record the data.

● To give the students a chance to familiarize with the actual working atmosphere

on the site including uncertainty situations.

● To provide them the opportunity of hands on experience of setting up the

theodolite for angle measurements.

6

APPARATUS USED

Theodolite

Theodolite is a basic surveying instrument that is commonly used in traversing. It is used to

measure horizontal and vertical angle. Theodolite is a tool used in the land surveying and

engineering industry. Moreover, it has been adapted for other specialized purposes as well.

Modern theodolites consist of telescope mounted to swivel both horizontally and vertically. The

levelling is accomplished with the aid of a spirit level and crosshairs in the telescope allow

accurate alignment with the object sighted. When the telescope is set up and adjusted precisely,

the two accompanying scales, that are vertical and horizontal, are read.

Tripod

A tripod is a device which is used to support surveying instruments. These surveying instrument

include theodolite, auto-level and so on. The tripod’s head supports the surveying instrument

whereas the feet are spiked to anchor the tripod to the ground. The level base provided will

ensure that the instrument is held securely, thus allowing accurate readings.

7

Plumb bob

A plumb bob or a plummet is a weight with a pointed tip on the bottom that is suspended from a

string and used as a vertical reference line. This instrument used in surveying to sight a point on

the ground that is not readily visible. They are used to set the instrument exactly over a fixed

datum marker, prior to taking fresh readings.

Levelling Staff

The levelling staff is simply a large ruler, available in lengths of 3, 4, or 5 metres and usually

made of aluminium with telescopic sections. The levelling staff is sectional so that can be

adjusted in length to allow for easy storage and transport. The sections have locking buttons to

ensure accurate length is maintained.

The “E” pattern is designed to make it easy to read a small section of the scale when see

through a telescope.

8

FIELD DATA 1


Station Height of

instrume

nt (m)

Station

sight

Stadia Reading (m) Horizontal Vertical

Facing Top Middle Bottom

A 131.0 B L 143.2 131.0 118.5 94º18’00” 90º28’40”

R 143.2 131.0 118.0

D L 149.5 131.0 112.0 90º06’10”

R 149.5 131.0 112.0

B 125.0 A L 137.0 125.0 112.0 71º55’50” 89º30’50”

R 137.5 125.0 112.5

C L 151.0 125.0 99.0 89º56’50”

R 151.0 125.0 99.0

C 176.0 D L 184.5 176.0 167.5 61º01’40” 88º04’30”

R 184.5 176.0 167.5

B L 202.0 176.0 149.5 89º33’00”

R 202.0 176.0 149.5

D 176.0 A L 194.5 176.0 157.0 134º22’50

”

89º13’30”

R 194.5 176.0 157.0

C L 184.5 176.0 167.5 88º51’20”

R 184.5 176.0 167.5

9


Station Height of

instrument

(m)

Station

sight


Top Middle Bottom

A 131.0 B 143.2 131.0 118.3 94º18’00” 90º28’40”

D 149.5 131.0 112.0 90º06’10”

B 125.0 A 137.3 125.0 112.3 71º55’50” 89º30’50”

C 151.0 125.0 99.0 89º56’50”

C 176.0 D 184.5 176.0 167.5 61º01’40” 88º04’30”

B 202.0 176.0 149.5 89º33’00”

D 176.0 A 194.5 176.0 157.0 134º22’50” 89º13’30”

C 184.5 176.0 167.5 88º51’20”

10

Station Field Angles

A B C D

94° 18’ 00” 71° 55’ 50” 61° 01’ 40” 134° 22’ 50”

Sum = 360° 96‘ 140“

361° 38’ 20”

11

4.3 Angular Error and Angle Adjustment

(4-2)(180°) = (2)(180°) = 360°, the sum of interior angle of the traverse must be 360°.

Total angular error = 360° - 361° 38’ 20’ = -1° 38’ 20”

Therefore, error per angle = -1° 38’ 20”/4 = -5900”/4 = -24’ 35” per angle

Station Field Angles Correction Adjusted Angles

A B C D

94° 18’ 00” 71° 55’ 50” 61° 01’ 40” 134° 22’ 50”

- 24’ 35” - 24’ 35” - 24’ 35” - 24’ 35”

93° 53’ 25” 71° 31’ 15” 60° 37’ 05” 133° 58’ 15”

Sum = 360° 96‘ 140“ 360° 0’ 0”

361° 38’ 20”

12


AB BC

Azimuth N: 180° - 93°53’25” = 86°06’35” 180° + (90° - 03°53’25” - 71°31‘15“) =

194°35’20”

Bearing: N 86°06’35” E 90° - 03°53’25” - 71°31’15” = S 14°35’20” W

CD DA

Azimuth N: 270° + (90°- 46°01’45”) = 313°58’15” 360°

Bearing: 60°37’05” - 14°35’20” = N 46°01’45” W 0°

13


Cos β Sin β L cosβ L sinβ

Station Bearing, β Length, L Cosine Sine Latitude Departure

A

B

C

D

A

N 86°06’35” E

S 14°35’20” W

N 46°01’45” W

0°

24.950

52.250

16.990

37.495

0.0678

0.9678

0.6943

1.000

0.9977

0.2519

0.7197

0.000

+ 1.69161

- 50.56755

+ 11.79620

+ 37.49500

+ 24.8926

- 13.1618

- 12.2277

0.0000

Sum = 131.685 + 0.41526 - 0.4969

Accuracy = 1: (P/Ec)

For average land surveying, an accuracy is typically about 1:3000.

Ec = [(Error in Latitude)2 + (Error in Departure)

2]

1/2

= [(0.41526)2 + (-0.4969)

2]

1/2

= 0.6476

P = 131.685

Accuracy = 1: (131.685 / 0.6478)

= 1: 203.28

∴ The traversing is not acceptable.

14


The Compass Rule

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

Where

∑∆y and ∑∆x = the error in latitude or in departure

P = the total length or perimeter of the traverse

L = the length of a particular course

Compass rule correction to latitude and departure

Unadjusted Correction Adjusted

Latitude Departure Latitude Departure Latitude Departure

A

+1.8418 +24.9225 0.0214 0.02230 +1.8632 +24.9448

B

-51.1381 -12.5647 0.0452 0.04697 -51.0929 -12.51773

C

+11.5328 -12.4758 0.0146 0.01515 +11.5474 -12.46065

D

+37.65 0 0.0323 0.03358 +37.6823 +0.03358

A

-0.1135 -0.118 0.1135 0.118 0.0 0.0

Check Check

15


Compute station coordinates

N2 = N1+ Lat1-2

E2 = E1+ Dep1-2

Where

N2 and E2 = the Y and X coordinates of station 2

N1 and E1= the Y and X coordinates of station 1

Lat 1-2 = the latitude of course 1-2

Dep 1-2 = the departure of course 1-2

Computation of station coordination

N coordination

*Latitude

E coordinate

*Departure

N(Y) E(X)

A 1037.6823 1000.00

+1.8632 +24.9448

B 1039.5455 1024.9448

-51.0929 -12.51773

C 988.4526 1012.42707

+11.5474 -12.46065

D 1000.00 999.96642

+37.6823 +0.03358

A 1037.0823 1000.00

16

Graph of Station Coordinate

17

FIELD DATA 2


Station Height of

instrume

nt (m)

Station

sight



A 176.0 B L 188.8 176.0 163.8 94º12’30” 89º30’20”

R 188.8 176.0 163.8

D L 194.8 176.0 157.2 89º27’20”

R 194.7 176.0 157.0

B 176.0 A L 188.7 176.0 163.7 71º57’20” 88º34’50”

R 188.8 176.0 163.8

C L 202.5 176.0 149.8 88º32’20”

R 202.5 176.0 149.8

C 176.0 D L 184.8 176.0 167.8 61º02’10” 88º04’20”

R 184.8 176.0 167.8

B L 202.5 176.0 149.8 88º06’10”

R 202.5 176.0 149.8

D 176.0 A L 194.8 176.0 157.2 132º44’00

”

89º09’00”

R 194.8 176.0 157.2

C L 184.8 176.0 167.8 89º09’00”

R 184.8 176.0 167.8

18


Statio

n

Height of

instrument

(m)

Station

sight


Top Middle Bottom

A 176.0 B 188.8 176.0 163.8 94º12’30” 89º30’20”

D 194.8 176.0 157.1 89º27’20”

B 176.0 A 188.8 176.0 163.8 71º57’20” 88º34’50”

C 202.5 176.0 149.8 88º32’20”

C 176.0 D 184.8 176.0 167.8 61º02’10” 88º04’20”

B 202.5 176.0 149.8 88º06’10”

D 176.0 A 194.8 176.0 157.2 132º44’00” 89º09’00”

C 184.8 176.0 167.8 89º09’00”

19


A B C D

94° 12’ 30” 71° 57’ 20” 61° 02’ 10” 132° 44’ 00”

Sum = 358° 115‘ 60“

359° 56’ 00”

20



Total angular error = 360° - 359° 56’ 00’ = 0° 04’ 00”

Therefore, error per angle = 0° 04’ 00”/4 = 0° 01’ 00” per angle


A B C D

94° 12’ 30” 71° 57’ 20” 61° 02’ 10” 132° 44’ 00”

+ 01’ 00” + 01’ 00” + 01’ 00” + 01’ 00”

94° 13’ 30” 71° 58’ 20” 61° 03’ 10” 132° 45’ 00”

Sum = 358° 115‘ 60“ 360° 0’ 0”

359° 56’ 00”

21


AB BC

Azimuth N: 180° - 94°13’30” = 85°46’30” 180° + (90° - 04°13’30” - 71°58’20”) =

193°48’10”

Bearing: N 85°46’30” E 90° - 03°53’25” - 71°58’20” = S 13°48’10”

CD DA

Azimuth N: 270° + (90°- 47°15’00”) = 312°45’00” 360°

Bearing: 61°03’10” - 13°48’10” = N 47°15’00” W 0°

22




A

B

C

D

A

N 85°46’30” E

S 13°48’10” W

N 47°15’00” W

0°

24.990

52.660

16.990

37.650

0.0737

0.9711

0.6788

1.000

0.9973

0.2386

0.7343

0.000

+ 1.8418

- 51.1381

+ 11.5328

+ 37.650

+ 24.9225

- 12.5647

- 12.4758

0.0000

Sum = 132.290 - 0.1135 - 0.1180


For average land surveying, an accuracy is typically about 1:3000.

Ec = [(Error in Latitude)2 + (Error in Departure)

2]

1/2

= [(-0.1135)2 + (-0.1180)

2]

1/2

= 0.1637

P = 132.290

Accuracy = 1: (132.290 / 0.1637)

= 1: 808.12


23


The Compass Rule


Where




Compass rule correction to latitude and departure



A

+1.69161 +24.8926 -0.078678 0.09415 +1.612932 +24.98675

B

-50.56755 -13.1618 -0.164767 0.19716 -50.732317 -12.96464

C

+11.7962 -12.2277 -0.053577 0.06411 +11.74262

3

-12.16359

D

+37.495 0 -0.118238 0.14148 +37.37676

2

+0.14148

A

0.41526 -0.4969 -0.41526 0.4969 0.0 0.0

Check Check

24



N2 = N1+ Lat1-2

E2 = E1+ Dep1-2

Where






N coordination

*Latitude E coordinate *Departure

N(Y) E(X)

A 1037.376762 1000.00

+1.612932 +24.98675

B 1038.989694 1024.98675

-50.732317 -12.96464

C 988.257377 1012.02211

+11.742623 -12.16359

D 1000.00 999.85852

37.376762 +0.14148

A 1037.376762 1000.00

25


26

FIELD DATA 3


Station Height of

instrument

(m)

Station

sight



A 176.0 B L 188.8 176.0 163.8 94º12’30” 89º30’20”

R 188.8 176.0 163.8

D L 194.8 176.0 157.2 89º27’20”

R 194.7 176.0 157.0

B 136.5 A L 149.0 136.5 123.5 71º55’50” 89º31’10”

R 148.5 136.5 124.0

C L 162.5 136.5 110.0 89º49’40”

R 162.5 136.5 110.0

C 176.0 D L 184.8 176.0 167.8 61º02’10” 88º04’40”

R 184.8 176.0 167.8

B L 202.5 176.0 149.8 88º06’10”

R 202.5 176.0 149.8

D 176.0 A L 194.8 176.0 157.2 132º44’00

”

89º09’00”

R 194.8 176.0 157.2

C L 184.8 176.0 167.8 89º09’00”

R 184.8 176.0 167.8

27


Station Height of

instrument

(m)

Station

sight


Top Middle Bottom

A 176.0 B 188.8 176.0 163.8 94º12’30” 89º30’40”

D 194.8 176.0 157.1 89º27’20”

B 136.5 A 148.8 136.5 123.8 71º55’50” 89º31’10”

C 162.5 136.5 110.0 89º49’40”

C 176.0 D 184.8 176.0 167.8 61º02’10” 88º04’40”

B 202.5 176.0 149.8 88º06’10”

D 176.0 A 194.8 176.0 157.2 132º44’00

”

89º09’00”

C 184.8 176.0 167.8 89º09’00”


A

B

C

D

94° 12’ 30”

71° 55’ 50”

61° 02’ 10”

132° 44’ 00”

Sum = 359° 54‘ 30“

28



Total angular error = 360° - 359° 54’ 30’ = 0° 05’ 30”

Therefore, error per angle = 0° 05’ 30”/4 = 0° 01’ 22.5” per angle


A

B

C

D

94° 12’ 30”

71° 55’ 50”

61° 02’ 10”

132° 44’ 00”

+ 01’ 22.5”

+ 01’ 22.5”

+ 01’ 22.5”

+ 01’ 22.5”

94° 13’ 52.5”

71° 57’ 12.5”

61° 03’ 32.5”

132° 45’ 22.5”

Sum = 359° 54‘ 30“ 360° 0’ 0”

29


AB BC

Azimuth N: 180° - 94°13’52.5” = 85°46’7.5” 180°+(90°-04°13’52.5”-71°57‘12.5“) = 193°48’55”

Bearing: N 85°46’7.5” E 90° - 04°13’52.5” - 71°57’12.5” = S

13°48’55”

CD DA

Azimuth N: 270° + (90°- 47°39’44.5”) = 313°20’15.5” 360°

Bearing: 61°03’32.5” - 13°48’55” = N 46°39’44.5” W 0°

30




A

B

C

D

A

N 85°46’7.5” E

S 13°48’55” W

N 46°39’44.5”

W

0°

24.99

52.25

16.99

37.65

0.0738

0.9711

0.6863

1.000

0.9973

0.2388

0.7273

0.000

+ 1.844

- 50.738

+ 11.660

+ 37.650

+ 24.922

- 12.477

- 12.357

0.0000

Sum = 131.88 0.416 0.088


For average land surveying, accuracy is typically about 1:3000.

Ec = [(Error in Latitude) 2 + (Error in Departure)

2]

1/2

= [(0.416) 2 + (0.088)

2]

1/2

= 0.421

P = 131.88

Accuracy = 1: (131.88 / 0.421)

= 1: 313.25


31


The Compass Rule


Where




Correction to latitude and departure



A

+ 1.844 + 24.922 -0.0788 -0.0167 + 1.7652 +24.9053

B

-50.738 -12.477 -0.1648 -0.0349 -50.9028 -12.5119

C

+ 11.660 -12.357 -0.0536 -0.0113 +11.6064 -12.3683

D

+ 37.650 0.000 -0.1188 -0.0251 +37.5312 -0.0251

A

+ 0.416 + 0.088 -0.4160 -0.0880 0.0000 0.0000

Checked Checked

32



N2 = N1+ Lat1-2

E2 = E1+ Dep1-2

Where






N Coordinate

*Latitude

E Coordinate

*Departure

N (Y) E (X)

A 1037.5312 1000.0000

+ 1.7652 +24.9053

B 1039.2964 1024.9053

-50.9028 -12.5119

C 988.3936 1012.3934

+11.6064 -12.3683

D 1000.0000 1000.0251

+37.5312 -0.0251

A 1037.5312 1000.000

33


34

AUTO LEVEL DISTANCE

Switching from using vertical angle taken from site. Using auto level to have a more

accurate distance over our 4 points. Advised from Mr. Chai Voon Chiet.

Station Station

Sighted

Levelling Reading (m) Distance

Top Bottom

A B 1.6110 1.3600 0.251

D 1.4890 1.1116 0.3774

B A 1.221 0.970 0.251

C 1.7300 1.2020 0.528

C B 1.5300 1.0020 0.528

D 1.3900 1.2107 0.1703

D A 1.4890 1.1116 0.3774

C 1.5505 1.3803 0.1702

Station Average Distance Distance x 100

A - B 0.251 25.10

B - C 0.528 52.80

C -D 0.1703 17.03

D - A 0.3774 37.74

Total 132.67

35

ADJUSTED FIELD DATA




A

B

C

D

A

N 86°06’35” E

S 14°35’20” W

N 46°01’45” W

0°

25.10

52.80

17.03

37.74

0.0678

0.9678

0.6943

1.000

0.9977

0.2519

0.7197

0.000

+ 1.703

- 51.098

+ 11.824

+ 37.740

+ 25.042

- 13.299

- 12.256

0

Sum = 132.67 + 0.169 - 0.513




2]

1/2

= [(-0.513) 2 + (0.169)

2]

1/2

= 0.540

P = 132.67

Accuracy = 1: (132.67 / 0.540)

= 1: 245.69


36




A

+ 1.703 + 25.042 -0.03197 + 0.09706 +1.67103 +25.13906

B

-51.098 -13.299 -0.06726 + 0.20416 -51.16526 -13.09484

C

+ 11.824 -12.256 -0.02170 + 0.06585 +11.80230 -12.19015

D

+ 37.740 0.000 -0.04807 + 0.14593 +37.69193 +0.14593

A

+ 0.169 - 0.513 -0.16900 + 0.51300 0.00000 0.00000

Checked Checked


N Coordinate *Latitude

E Coordinate *Departure

N (Y) E (X)

A 1037.69193 1000.0000

+1.67103 +25.13906

B 1039.36296 1025.13906

-51.16526 -13.09484

C 988.19770 1012.04422

+11.80230 -12.19015

D 1000.0000 999.85407

+37.69193 +0.14593

A 1037.69193 1000.000

37


38




A

B

C

D

A

N 85°46’30” E

S 13°48’10” W

N 47°15’00” W

0°

25.10

52.80

17.03

37.74

0.0737

0.9711

0.6788

1.000

0.9973

0.2386

0.7343

0.000

+ 1.849

- 51.275

+ 11.560

+ 37.74

+ 25.032

- 12.587

- 12.506

0.0000

Sum = 132.67 - 0.126 - 0.061




2]

1/2

= [(-0.126) 2 + (-0.061)

2]

1/2

= 0.140

P = 132.67

Accuracy = 1: (132.67 / 0.140)

= 1: 947.64


39




A

+ 1.849 + 25.032 +0.02384 + 0.01154 +1.87284 +25.04354

B

-51.275 -12.587 +0.05015 + 0.02428 -51.22485 -12.56272

C

+ 11.560 -12.506 +0.01617 + 0.00783 +11.57617 -12.49817

D

+ 37.740 0.000 +0.03584 + 0.01735 +37.77584 +0.01735

A

- 0.126 - 0.061 +0.12600 + 0.061 0.00000 0.00000

Checked Checked




N (Y) E (X)

A 1037.77584 1000.0000

+1.87284 +25.04354

B 1039.64868 1025.04354

-51.22485 -12.56272

C 988.42383 1012.48082

+11.57617 -12.49817

D 1000.0000 999.98265

+37.77584 +0.01735

A 1037.77584 1000.000

40


41




A

B

C

D

A

N 85°46’7.5” E

S 13°48’55” W

N 46°39’44.5”

W

0°

25.10

52.8

17.03

37.74

0.0738

0.9711

0.6863

1.000

0.9973

0.2388

0.7273

0.000

+ 1.852

- 51.273

+ 11.688

+ 37.740

+ 25.032

- 12.608

- 12.386

0.0000

Sum = 132.67 + 0.007 +0.038




2]

1/2

= [(0.007) 2 + (0.038)

2]

1/2

= 0.039

P = 132.67

Accuracy = 1: (132.67 / 0.039)

= 1: 3401.79

∴ The traversing is Acceptable.

42




A

+ 1.852 + 25.032 -0.00132 - 0.00719 +1.85068 +25.02481

B

-51.273 -12.608 -0.00279 - 0.01512 -51.27579 -12.62312

C

+ 11.688 -12.386 -0.00090 - 0.00488 +11.68710 -12.39088

D

+ 37.740 0.000 -0.00199 - 0.01081 +37.73801 -0.01081

A

+ 0.007 + 0.038 -0.00700 - 0.03800 0.00000 0.00000

Checked Checked




N (Y) E (X)

A 1037.73801 1000.0000

+1.85068 +25.02481

B 1039.58869 1025.02481

-51.27579 -12.62312

C 988.31290 1012.40169

+11.68710 -12.39088

D 1000.0000 1000.01081

+37.73801 -0.01081

A 1037.73801 1000.000

43


44

DISCUSSION

Traversing is a closed loop traverse. The equipment that we utilized overall are

the theodolite, tripod and plumb bob. The fieldwork was carried out at Taylor’s

University Lakeside Campus staff’s car park, near Academic Block E.

Each group was required to mark at least four points so that the traversing work

can be done. Furthermore, we were required to measure the horizontal and vertical

angles at the four points which are then labelled as point A, B, C and D.

One of the apparent obstacles in doing the fieldwork was to balance the air

bubble in the spirit level in order to get accurate results. We realised that the 5 person

count in each group is the optimal head-count to get our job done quickly and smoothly,

as each person was assigned to one specific task throughout the fieldwork.

In addition, with guidance from our lecturer, Mr Chai, we were able to identify the

important steps of the fieldwork and also the proper way to operate the theodolite.

However, after repeating the fieldwork 3 times, we were still unable to obtain an

accurate and acceptable result. We realised that even the slightest error in taking the

readings can result in final readings that stray off too much from the acceptable error.

We took our second set of readings which is more accurate than the first set, but still not

closed to the acceptable error. Mr. Chai then asked another group and my group, which

was using the same instrument number to do together. Since both of our group could

not get the accuracy. We went down and took the 3rd reading, due to raining condition, it

was very hard to mark down what was the top and bottom reading. Mr. Chai told us that

3 problems will arise such as human error, instrument error and random error such as

heavy wind, raining, and others.

Even so we manage to take all 4 points. However, the result was still the same,

we could not get the accuracy we wanted. Therefore, Mr. Chai advised us again to try

using the auto level to measure the distance, because the auto level can measure much

accurate. In order to see if our angle has problem or the distance or even both, we went

down and take the distance. Thankfully we managed to close it with our 3rd data after

using the auto level distance.

In conclusion, practical experience in surveying is very important aside from

everything we have learnt in the classroom.

Education

Site Surveying Traversing