SCHOOL OF ARCHITECTURAL,

BUILDING &

DESIGN

BACHELOR OF QUANTITY SURVEYING (HONOURS)

AUGUST 2014

[QSB 60203] SITE SURVEYING

Fieldwork 2

Group Member: Eley Chong Shu Hui 0319458

Melvin Lim 0315772

Moy Chin Hoong 0314014

Muhammad Hakim 0310371

Lecturer : CHAI VOON CHIET

Contents

Contents Pages

Objective 1

Introduction to auto level 2

Field Data 3

Adjusted Data 4-7

Summary 8

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 enable us to know the methods to measure horizontal angles between

lines.

To allow us to learn more about the life being a quantity surveyor.

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 have the teamwork while carrying out the fieldwork.

To enable us to learn how to analyze the data collected.

To allow us to understand how to distribute different types of error from the

data collected on field.

To enable us to have the knowledge in reading the positions on ranging rods.

To enable us to have a basic knowledge on how to set up the points.

To allow us to have the ability to undertake the site measurements and

calculations.

To enable us to know the precautions should be taken while using Theodolite.

Introduction to theodolite

A theodolite is a precision 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. A modern theodolite consists of a movable telescope mounted

within two perpendicular axes, the horizontal or trunnion axis, and the vertical axis.

When the telescope is pointed at a target object, the angle of each of these axes can

be measured with great precision, typically to seconds of arc.

Theodolites may be either transit or non-transit. Transit theodolites are those in

which the telescope can be inverted in the vertical plane, whereas the rotation in the

same plane is restricted to a semi-circle for non-transit theodolites. Some types of

transit theodolites do not allow the measurement of vertical angles.

The builder's level is sometimes mistaken for a transit theodolite, but it measures

neither horizontal nor vertical angles. It uses a spirit level to set a telescope level to

define a line of sight along a horizontal plane.

Electronic Theodolite

Field Data

Station Field Angles

A 90°12’ 50”

B 90° 11’ 45”

C 89° 57’ 55”

D 89° 30’ 46”

Sum = 359° 53’ 16”

A

90° 12’ 50”

D

89° 30’ 46”

B 90° 11’ 45” 13.23 m

51.64 m

13.67 m

51.73 m

C

89° 57’ 55”

Adjusted Data

As known the sum of the interior angles in any loop transverse is equal to (n - 2)

(180°) for geometric consistency, therefore

(4 – 2) (180°) = 2 (180°) = 360°

The total angular error = 360° 00’ 00” - 359° 53’ 16” = 0° 6’ 44”

Therefore, error per angle = 0° 6’ 44”/4 = 0° 1’ 41” per angle

Station Field Angles Correction Adjusted Angles

A 90°12’ 50” +0° 1’ 41” 90° 14’ 31”

B 90° 11’ 45” +0° 1’ 41” 90° 13’ 26”

C 89° 57’ 55” +0° 1’ 41” 89° 59’ 36”

D 89° 30’ 46” +0° 1’ 41” 89° 32’ 27”

Sum = 359° 53’ 16” 360° 0’ 0”

Computation for course azimuths

Station Adjusted Angles Course Azimuths

A-B 90° 14’ 31” 90° 14’ 31”

B-C 90° 13’ 26” 90° 14’ 31” + 90° 13’ 26” - 180° = 0° 27’ 57”

C-D 89° 59’ 36” 0° 27’ 57” + 89° 59’ 36” + 180° = 270° 27’ 33”

D-A 89° 32’ 27” 270° 27’ 33” + 89° 32’ 27” - 180° = 180° 0’ 0”

Computations for Latitude and Departure

Cos ∂ Sin ∂ L cos ∂ L sin ∂

Station Azimuth, ∂ Length, L Cosine Sine Latitude Departure

A

90° 14’ 31” 13.23 -0.0042 1.0000 -0.056 +13.230

B

0° 27’ 57” 51.64 1.0000 0.0081 +51.640 +0.418

C

270° 27’ 33” 13.67 0.0080 -1.0000 +0.109 -13.670

D

180° 0’ 0” 51.73 -1.0000 0.0000 -51.730 0

A

Perimeter(P) = 130.27 m Sum of latitudes = ∑∆y = -0.037 m

Sum of departures = ∑∆x = -0.022 m

Error in departure ∑∆x = -0.022 m

A

Error in latitude

∑∆y = -0.037 m

Ec, Total Error

0.043 m

A’

Accuracy = 1: (P/Ec)

Therefore, the accuracy = 1: (130.27/ 0.043)

= 1: 3029.5

= 1: 3030

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

Thus, the accuracy of field is acceptable.

Adjust Course Latitudes and Departures

Unadjusted Corrections Adjusted

Station Latitude Departure Latitude Departure Latitude Departure

A

-0.056 +13.230 0.003 0.002 -0.053 +13.232

B

+51.640 +0.418 0.015 0.009 +51.655 +0.427

C

+0.109 -13.670 0.004 0.002 +0.113 -13.668

D

-51.730 0 0.015 0.009 -51.715 +0.009

A

Sum = -0.037 -0.022 0.037 0.022 0.0 0.0

Computation of Station Coordinates

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

Station N Coordinate* Latitude E Coordinates* Departure

A 100.000 100.000

-0.053 +13.232

B 99.947 113.232

+51.655 +0.427

C 151.602 113.659

+0.113 -13.668

D 151.715 99.991

-51.715 +0.009

A 100.00 100.000

The adjusted loop traverse plotted by coordinates:

Y axis (north)

N 100.000E 100.000

N 99.947E 113.232

N 151.602E 113.659

N 151.715E 99.991

0

50

100

150

200

0 50 100 150

A B

C D

X axis

(East)

Summary

A theodolite is a precision 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. We were assigned to use this instrument for angle calculation. In this

experienced fieldwork, we needed more than 2 hours to complete the angle

calculation. The first thing we did was setting up the instrument. We leveled the

theodolite before we took the measurement. We took extra time to do that because

to stabilize the instrument was a bit hard.

Firstly, the theodolite is placed at station A and need to adjust the theodolite until it is

in horizontal level. Then, the station A, B, C, D must be stated on the site to form a

loop traverse by using the small stones. We use theodolite to measure the angles of

four stations as our field data. During 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 some distribution error.

Our total angular for the loop traverse is 359° 53’ 16” and the total angular error is

about 0° 6’ 44”, therefore for each angle, it has 0° 1’ 41” error in angle. Before adjust

the readings we get, the accuracy (1:3000) is important to be calculated to ensure

the error of closure and accuracy are acceptable. Fortunately, the accuracy is about

1: 3030 that is a typical accuracy for average land surveying.

The field data is adjusted and the coordinates of four stations are stated at the graph

with assuming the coordinates of station A is (100.000, 100.000).