CEVB 211 SURVEYING PRACTICAL TRAINING

LABORATORY EXPERIMENT NO. 5

THE APPLICATION OF DIGITAL THEODOLITE – CONTROL TRAVERSE

SECTION: 03

NAME IDMUHAMMAD FIKRIL AZIM BIN ABDUL SANI CE094946

DATE OF LABORATORY SESSION : 10 DECEMBER 2015

DATE OF REPORT SUBMISSION : 17 DECEMBER 2015

LAB INSTRUCTOR : DR. AL MAHFOODH ALI NAJAH AHMED

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TABLE OF CONTENT

CONTENT PAGE

Table of Content 2

Summary/Abstract 3

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Introduction & Objective 3-4

Materials or Equipments 4-5

Procedure 5-7

Results & Calculations 8

Discussion 9

Conclusion 9

References 9

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PROBLEM STATEMENT

As a civil engineer, I am required to apply the knowledge of traversing for a new project site.

ABSTRACT/SUMMARY

The contour is the relative position of points in a plan that is represented by a map.

Contouring is defined as a contour line joining points of equal heights or altitude. The vertical distance between successive contours is known as the vertical interval.

Contour lines are continuous lines and cannot meet or cross any other contour line, nor can any one line split or join any other line, except in the case of a cliff.

The height between the successive contours is called the vertical interval or contour interval and is always constant over a map or plan.

INTRODUCTION

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Theodolite Target

It is an instrument for measuring directions, can be ‘optical’ where glass circles are used to measure direction and usually these days they are digital.

A theodolite is an instrument which is capable of measuring angles to the nearest whole second. This can be done for both vertical and horizontal angles. Vertical angles are required for the calculation of the elevation of points for example, the reduction of slope distance to the horizontal. It also eliminates the manual reading of scales on graduated circles.

OBJECTIVE

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To apply the knowledge of using digital theodolite, establish control traverse and adjust the observation of data.

Apparatus

1. Digital Theodolite (1 unit) + A1 size batteries (6 units)2. Traversing Target (2 unit)3. Tripod (3 units)4. Hammer, nails and spray

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Station Angle Adjusted Angle

Length Whole Circle Bearing

∆E ∆N Correction Adjusted Coordinates

∆E ∆N ∆E ∆N East North

A 93°25’30” 93°24’41.25” 6.5 264°00’00” -6.464 -0.680 -0.599 +0.080 -7.063 -0.600 100.000 100.000

B 65°46’55” 65°46’6.25” 7.3 149°46’6.25” 3.676 -6.307 -0.672 +0.089 +3.004 -6.218 92.937 99.400

C 131°35’25” 131°34’36.2” 6.9 101°20’42.4” 6.765 -1.357 -0.635 +0.085 +6.130 -1.272 95.941 93.182

D 69°15’25” 69°14’36.25” 8.1 350°35’18.6” -1.325 7.991 -0.746 +0.099 -2.071 +8.090 102.071 91.910

Sum 360°03’15” 360°00’00” 28.8 +2.652 -0.353 -2.652 +0.353 0 0

Results

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Sample Calculation

Total angle in polygon

= (n-2) x 180

= (4-2) x 180

= 360°

Error of sum of angles:

= 360°03’15” - 360°00’00”

= 0°03’15”

Angles correction:

= 0°03’15” / 4

= 0°0’48.75”

Adjusted Angle A

= 93°25’30” - 0°0’48.75”

= 93°24’41.25”

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Whole Circle Bearing for station B

= (264°00’00” + 65°46’6.25”) - 180°00’00”

= 149°46’6.25”

∆E for station A

= L sin (WCB)

= 6.5 sin 264°00’00”

= -6.464

∆N for station A

= L cos (WCB)

= 6.5 cos 264°00’00”

= -0.679

Correction for ∆E for station A

= - [Total ∆E x (Length/Total length)]

= - (+2.652) x (6.5/28.8)

= -0.599

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Correction for ∆N for station A

= - [Total ∆N x (Length/Total length)]

= - (-0.353) x (6.5/28.8)

= +0.080

Adjusted ∆E for station A

= Original ∆E + Correction

= -6.464 + -0.599

= -7.063

Adjusted ∆N for station A

= Original ∆N + Correction

= -0.680 + 0.080

= -0.600

East Coordinates for station B

= 100.000 + Adjusted ∆E

= 100.000 + (-7.063)

= 92.937

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North Coordinates for station B

= 100.000 + Adjusted ∆N

= 100.000 + (-0.600)

= 99.400

Area of closed traverse

= 12|x1 x2 x3 x 4 x 5y 1 y 2 y 3 y 4 y5|

= 12|100.000 92.937 95.941 102.071 100.000

100.000 99.400 93.182 91.910 100.000|

= 37625.093 – 37532.415 = 92.678

= 12

x (92.678)

= 46.339 m2

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Table 2: Traverse Form

Sample calculation:

1. Horizontal angle B and C

360°00’00” - 313°00’35” = 46°59’25”

Mean = (46°59’25” + 46°59’25”)/2 = 46°59’25”

2. Point B Vertical Distance

Face Right = 360°00’00” - 269°10’00” = 90°50’00”

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Mean = (90°49’55” + 90°50’00”)/2 = 90°49’57.5”

Discussion

The main objective is from this experiment is understand more about the setting up and calculation of the Theodolite. From the data obtained, the difference for horizontal angle is 00°00’00” and vertical angle is 00°04’05”. We need to transit from the face left to face right for about two or more times for more accurate reading. By transiting, the mean value is used as the actual angle.

Errors for this experiment includes the prism are not pointed towards the theodolite and even exhausted batteries. To eliminate the error, we just take new batteries and for the prisms problems, the prisms is set up and adjusted carefully. So, to reduce the error, tripod’s leg is anchored firmly. The bubble level also needed to be checked before and after each reading. EDM errors could be exist when carry out the reading of the theodolite and the targets.

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Conclusion

I am able to know how to measure the horizontal and vertical angles of theodolite and gain knowledge of how to handle the equipment during the field work .Theodolite must be centred on the point using plum bob. The mean horizontal between point B and C is both 46°59’25” while the mean vertical angle of B is 90°49’57.5” and C is 90°15’2.5”. We also know how to adjust the reading system of the theodolite angle at the right plane. Centring and levelling the instrument was to ensure the horizontal angle that was measured. I also know what types of theodolite are classified which are Vernier theodolite, Optical theodolite, Electronic theodolite. We also know now about that a modern theodolite consists of a movable telescope mounted within two perpendicular axes-horizontal axis and vertical axis.

References

http://www.slideshare.net/x3HwaN/site-surveying-report-ii

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