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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= 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


= 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

http://www.state.nj.us/transportation/eng/documents/survey/Chapter5.shtm

http://surfcivil.blogspot.my/2010/05/traverse-surveying.html

Site survey Fieldwork 2 traversing

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