SCHOOL OF ARCHITECHTURE, BUILDING AND DESIGN

BACHELOR OF QUANTITY SURVEYING

FIELDWORK 2

TRAVERSING

NAME STUDENT ID

STEVEN CHAN KAI TIONG 0319850

TAY SY MIN 0320813

VOON SZE LUN 0315032

WONG GENG SEN 0321690

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Content

Content Pages

Cover page 1

Content page 2

Introduction 3

Outline Apparatus 4 - 6

Objective 7

Tabulation Data 8

Adjustment Data 9 - 11

Conclusion 12

Reference s 13

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Introduction

Traverse survey

- Traversing is one kind of method that used in the field of surveying to establish control networks. A traverse is a series of straight lines that are used to connect a series of selected points. These selected points are called traverse stations where distance and angle measurements are made. The relative positions of the traverse stations are then computed using some coordinate systems.

2 types of traverse survey: closed traverse and open traverse.

1. Closed traverse: this traverse starts at a point and ends at the same point. Areas that are suitable for locating are lakes, woods, and for survey of large areas.

2. Open traverse: this traverse originates at a starting station, then proceeds to its destination, and then ends at a station whose relative position is not previously known. This traverse is suitable for surveying a long narrow strip of land.

The least desirable type of traverse is the open traverse because this traverse provides no check on fieldwork or starting data. Because of this, the planning of a traverse always provides for closure of the traverse. So, the traverses are closed in all cases where time permits. Those surveyors adjust the measurements by computations to minimize the effect of accidental errors made in the measurements and the large errors are corrected.

Source from: http://www.floridageomatics.com/publications/gfl/chapter-three.htm

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Outline Apparatus

Theodolite - is an instrument that used to measure angles and directions. It's mounted on an adjustable tripod and has a spirit level to show when it is horizontal.

Tripod

- is a device used to support any one of a number of surveying instruments, such as theodolites, total stations, levels or transits.

Horizontal bubble level

- is an instrument used to indicate the horizontal level. It is a slightly curved glass tube which is incompletely filled with alcohol.

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Plumb bob

- is a weight which is suspended from a string and used as a vertical reference line. Set the instrument exactly over a fixed survey marker, or to transcribe positions onto the ground for placing a marker.

Theodolite pole

- used as a stand to indicate the angle

between two or more points in an enclosed area.

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Theodolite

All theodolites have the same common features which can be described as follows:

1. Targeting sight

2. Objective lens

3. Horizontal clamp knob

4. Horizontal tangent screw

5. Display window

6. Operating keys

7. Levelling screws

8. Tripod base plate

9. Optical plummet

10. Instrument centre mark

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Objectives

1. To allow student to have a better understanding on the process of using theodolite rather

than listening to the lecture in class.

2. To allow student to gain experience on how to use theodolite, for example: setting up,

collaborating, calculating and recording data.

3. To enable student to know the methods of measuring the angles and lines.

4. To enable student to know the precautions that should be taken while using the

Theodolite.

5. To allow student to have the experience of doing fieldwork under actual working

environment in site such as working under the hot weather.

6. To allow student to understand the importance of teamwork while carrying out the

fieldwork.

7. To determine how to analyse the data collected from the fieldwork.

8. To allow student to understand how to distribute different types of error from the data

collected on field.

9. To enable student to learn how to read the positions on ranging rods.

10. To enhance the knowledge on how to set up the points for the fieldwork.

11. To allow student to have the ability to finish the site measurements and calculations

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Field Data

Station Field Angles

A 89°07’ 20”

B 92° 24’ 40”

C 88° 45’ 00”

D 89° 55’ 20”

Sum 360° 12’ 20”

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A89°07’ 20” B

92° 24’ 40”

D89° 55’ 20”

28.35 m

62.24 m

29.51 m

61.60 m

C88° 45’ 00’’

AUNGULAR ERROR AND ANGULAR ADJUSTMENTS

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

Hence, total angle errors = (360° 00’ 00’) - (360° 12’ 20’’) = -0° 12’ 20’’

Therefore, error per angle = (-0° 12’ 20’’)/4 = -0° 3’ 5’’

Station Field Angles Correction Adjusted Angles

A 89°07’ 20” -0° 3’ 5” 89° 4’ 15”

B 92° 24’ 40” -0° 3’ 5” 92° 21’ 35”

C 88° 45’ 00” -0° 3’ 5” 88° 41’ 55”

D 89° 55’ 20” -0° 3’ 5” 89° 52’ 15”

Sum 360° 12’ 20” 360° 00’ 00”

Station Adjusted Angles Course Azimuths

A-B 89° 4’ 15” 89° 4’ 15”

B-C 92° 21’ 35” 89° 4’ 15” + 92° 21’ 35” - 180° = 1° 25’ 50’’

C-D 88° 41’ 55” 1° 25’ 50” + 88° 41’ 55” + 180° = 270° 7’ 45’’

D-A 89° 52’ 15” 270° 7’ 45” + 89° 52’ 15” - 180° = 180° 0’ 0’’

Computation for course azimuths

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Computations for Latitude and Departure

Length Cos β Sin β L cos β L sin βStation Azimuth, β L(m) Cosine Sine Latitude Departure

A89° 4’ 15” 61.60 +0.0162 +0.9999 +0.9989 +61.5919

B1° 25’ 50” 28.35 0.9997 +0.0250 +28.3412 +0.7078

C270° 7’ 45” 62.24 +0.0023 -1.0000 +0.1403 -62.2398

D180° 0’ 0” 29.51 -1.0000 0.0000 -29.5100 0.0000

APerimeter(P) = 181.70 m Sum of latitudes = ∑∆y = -0.0296 m

Sum of departures = ∑∆x = 0.0599m

Error in departure ∑∆x = 0.0599 m

Error in latitude

∑∆y = -0.0296 m

Accuracy = 1: (P/Ec)

Therefore, the accuracy = 1: (181.70/0.0668)

= 1: 2720.05988

= 1: 2700

For average land surveying an accuracy of about 1: 3000 is typical.

Hence, the accuracy of field is acceptable.

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Total Error = 0.0668m

Adjusted Course Latitudes and Departures

Unadjusted Corrections Adjusted

Station Latitude Departure Latitude Departure Latitude DepartureA

+0.9989 +61.5919 0.0101 -0.0203 +1.0090 +61.5716B

+28.3412 +0.7078 0.0046 -0.0093 +28.3458 +0.6985C

+0.1403 -62.2398 0.0101 -0.0205 +0.1504 -62.2603D

-29.5100 0.0000 0.0048 -0.0098 -29.5052 -0.0098A

Sum -0.0296 0.0599 0.0296 -0.0599 0.0000 0.0000

Computation of Station Coordinates

Assume that the coordinates of A is (100.000, 100.000)

Station Adjusted Latitude

Adjusted Departure

N Coordinate Latitude

E CoordinatesDeparture

A 100.000 100.000+1.0090 +61.5716

B 101.0090 161.5716+28.3458 +0.6985

C 129.3548 162.2701+0.1504 -62.2603

D 129.5052 100.0098-29.5052 -0.0098

A 100.00 100.000

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Correction in Latitude of AB = Total LatitudeMisclosureTraverse Perimeter

× Lengt hof AB

Correction in Departure of AB = Total Departure Misclosure

Traverse Perimeter× Lengthof AB

Summary

In this fieldwork, a theodolite is being used. There were only four theodolite in the campus hence we shared the theodolite with another group and used the pacing method to obtain our length of each course but we failed to get an accuracy of at least 1:3000. After that, we used the tape-measure the length of each course. In order to get the most accurate reading possible, our lecturer, Mr. Chai taught us to use the theodolite to guide our tape-measure to make it is in as straight line.

Our error in departure is 0.0599 and our error in latitude is -0.0274. The total error is 0.0659. Using the following formula, we calculated the accuracy of our traverse survey:

Accuracy = 1: Perimeter/ Error Closure

We obtained an accuracy of 1:2700. For average land surveying an accuracy of 1:3000 is typical. Therefore, our traverse survey is acceptable.

The result of this fieldwork is interesting and satisfying. Thank to our lecturer, Mr. Chai who taught us how to do the fieldwork and helped us to gain some knowledge on how to use a theodolite so we can do the fieldwork smoothly and successfully.

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Reference

Bob Vila (n.d.). The Plumb Bob. (Website). Retrieved on 20 November 2014 from

http://www.bobvila.com/articles/495-the-plumb-bob/#.VHbzzTGLUeoh

EngineerSupply, LLC © Copyright 1999-2015. (Website)

http://www.engineersupply.com/theodolites.aspx

Federal Geodetic Control Committee (1984). Standard Specifications for Geodetic Control Networks. Retrieved on 20 November form

http://www.ngs.noaa.gov/FGCS/tech_pub/1984-stda-specs-geodetic-control-networks.pdf

Farlex clipart collection. © 2003-2012 Princeton University, Farlex Inc.

http://www.thefreedictionary.com/ranging+rod

http://nptel.ac.in/courses/105107122/modules/module9/html/28-5.htm#

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