surveying practical report - cartography kevinly

8/13/2019 Surveying Practical Report - Cartography Kevinly

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SURVEYING PRACTICAL REPORT

CARTOGRAPHY

Bimasena Heribowo 1206292351

Christopher Kevinly 1206223846

Wednesson Lawijaya 1206230593

Date of Practicum : Friday, November 15th2013

Practical Assistant : Danu Irawan

Date Approved :

Grade :

Signature :

LABORATORY OF SURVEYING AND MAPPING

DEPARTMENT OF CIVIL ENGINEERING

FACULTY OF ENGINEERING

UNIVERSITAS INDONESIA

DEPOK

2013


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University of Indonesia

1 | C a r t o g r a p h y

1. Objective of The Practical Works:This practical activity is done in order to measure the area of GK field

and the contour of its surrounding by using geometrical data on the ground to a

flat plane with a specific scale.

2. Apparatus Theodolite 1 unit Pointer 4 units Umbrella 1 unit (optional) Surveying staff 1 unit Tripod 1 unit Measuring tape 1 unit Ruler 1 unit

3. Principal TheoremCartography is a surveying activity which shows the vertical and

horizontal aspects of the area measured. In doing Cartography, the object

which is measured can be both natural and artificial object.

In short, cartography can be stated as the measurement of horizontal

and vertical aspects of a location or area which will be mapped. The

measurement of the plane can be done by some methods; terestrical,

photogrammetric or other methods. Terestrical method is a method which uses

theodolite as its instrument, while photogrammetric method is done by taking

images from the air by using airplane or balloon. Photogrammetric mapping

cannot be done without reference which is taken by terestrical measurement,

from setting the basic control point to scope determination.

In this practical activity, the determination of the distance between

points measured is exactly the same with the previous practical activities,

which uses the following formula:

( )


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Where:

UC = Upper Crosshair

LC = Lower Crosshair

D = Distance measured

While in order to determine the area of the building, the following

formula applies:

Where:

A = area

L = length

W = width

Note that there are two methods which are used in cartography:

1) Offset MethodIn this method, the main apparatus which are used are measuring tape and

a geometrical shaper which is used to create prism. The offset method is

consists of two ways:

i. Perpendicular Line method:Detailed points which are

projected perpendicularly

against the ruler line AB,

then the angles aremeasured by measuring

aa, bb, cc and dd, the

relative position of point a,

b, c and d can be

determined.


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ii. Interpolation Method:The detailed points are tied with straight lines on the

measuring line. There are two methods:

i. Interpolation of random pointsThis is done by

determining

random lines on

the measuring line

AB (point a, a,

d, d, c and c).

Make sure that triangle aaa, ddd, and ccc are

equilateral triangle or isosceles triangle. By measuring the

distance of Aa, Aa, Ad, Ad, Ac, Ac, Bc, Bc, Bd,

Bd, Ba, Ba, aa, aa, dd, dd, cc, cc, the position of

point a, b and c can be determined.

ii. Side Elongation method:

iii. Simple Trilateralization method


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2) Polar MethodApparatus: compass theodolite or repetition theodolite

1. With Azimuth and distance

2. With angles and distance

- Angle measurement can be done from engineering principal point

- Plane distance measurement can be done by tape or EDM

By doing cartography, geometrical data can be gained from the

field work. By using this geometrical data, these data will be expressed on adrawing media which possess right scaling. The drawing which is done is

usually in form of contour map which forms contour lines. By using these

contour lines, the field situation can be determined. This situation is based

on the difference of height of every point.

By definition, contour lines are lines which connect points which

possess a same elevation. The other name of the contour line is tranches

line. The properties of the contour line are as below:

A contour line indicates that all elements along the line possess asame elevation.

Contour lines are not intersecting each other and not branching. Contour lines which are densely packed indicate that the area which

is expressed possess step elevation, while a large distance between

the lines indicates that the plane is relatively flat.

U shaped contour line indicates mountains back
http://bp1.blogger.com/_Sqzc7gn78xY/RnBDF3jA1kI/AAAAAAAAAEM/nOhocnl8dfw/s1600-h/013.jpg


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V-shaped contour line indicates a valley / canyon.

These contour lines are used for many purposes, such as:

Cutting and filling planning. By doing contour map, the volume ofcutting and filling works can be estimated.

The formulas which are used in this practical activity are:

T = (HI-CC)

D = (UC-LC)

( [])

( [])

Where:

T = height difference between the theodolite and the measured plane

HI = height of instrument

CC = Center crosshair

D = distance between the theodolite and the measured plane

UC = Upper crosshair

LC = Lower crosshair

4. Practical StepsPreparation:

1) Make the sketch of the structure, in this case, GK field.2)

Set the benchmark which will be used as measuring point.

3) Prepare the apparatus which are wanted to be used4) Measure the dimension of the field by using the measuring tape.\

Practical Activity:

1) Setting the theodolite rightly on its first measuring point, in this case, pointA, and then measures the height of the theodolite.


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2) Measure the upper crosshair, the middle crosshair, the lower crosshair andthe horizontal angle of the point B, 2, 1, 4 and D from point A.

3) Then move the theodolite to point B, and then shoot point A, 1, 2, 3, andC.

4) Move the theodolite to point C, and then shoot point B, 2, 3 and D.5) Move the theodolite to point D, and then shoot point A, 1, 2, 3 and C

5. Experimental Data and Data ProcessingSituation Image:

Experimental Data:

Theodolite at point A:

Apparatus

Position

Point

MeasuredUC CC LC

DField

(m)

DOptical

(UC-LC)

(m)

Relative

Error

T

(HI-CC)

(cm)

A

(Height of

Instrument

= 149.5

cm)

B 124.2 111 98 26.14 26.2 0.23% 38.5

2 174.3 162.5 150.8 23.9 23.5 1.67% -13

1 156.5 154 152.5 3.23 4 23.84% -4.5

4 163.3 156 148.5 14.9 14.8 0.67% -6.5

D 146.3 134.2 122.5 24.18 23.8 1.57% 15.3


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Theodolite at Point B:

Apparatus

Position

Point

Measured

UC CC LCDField

(m)

DOptical

(UC-LC)

(m)

Relative

Error

T

(HI-CC)

(cm)

B

(Height of

Instrument

= 119.2

cm)

C 166.2 158.1 149.1 17.2 17.1 0.58% -38.9

3 168.6 161 153.5 15.17 15.1 0.46% -41.8

2 172.4 171 169.1 4.76 3.3 30.67% -51.8

1 177.7 165 152 24.6 25.7 4.47% -45.8

A 174 160.3 146.9 26.8 27.1 1.12% -41.1

Theodolite at point C:

Apparatus

Position

Point

MeasuredUC CC LC

DField

(m)

DOptical

(UC-LC)

(m)

Relative

Error

T

(HI-CC)

(cm)

C

(Height of

Instrument

= 120.5

cm)

D 129.2 114.1 98.9 30.6 30.3 0.98% 6.4

3 126.3 124.4 122.4 4.06 3.9 3.94% -3.9

2 143.2 135.7 128.1 15 15.1 0.67% -15.2

B 93 84 74.9 17.7 18.1 2.26% 36.5

Theodolite at Point D:

Apparatus

Position

Point

MeasuredUC CC LC

DField

(m)

DOptical

(UC-LC)

(m)

Relative

Error

T

(HI-CC)

(cm)

D

(Height of

Instrument

= 152.5)

A 172.3 160.5 148.5 24.18 23.8 1.57% -8

1 176.5 165.6 155 21.3 21.5 0.94% -13.1

4 176.8 171.5 166.5 10.3 10.3 0.00% -19

3 175 161 147 28.5 28 1.75% -8.5

C 173.8 158.8 144 30.6 29.8 2.61% -6.3


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Horizontal angles:

Point A

Point

Measured Horizontal Angle

B 0o0000

2 6o4655

1 58o1335

4 84o4550

D 98o3315

Point B

Point

MeasuredHorizontal Angle

C 0o0000

3 10o2715

2 40o1830

1 83o2950

A 89o5215

Point CPoint

Measured

Horizontal Angle

D 0o0000

3 58o5450

2 92o4945

B 101o4945

Point DPoint

MeasuredHorizontal Angle

A 0o

0000

1 5o2305

4 20o3430

3 63o1415

C 69o5700


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By using point A as the benchmark (point [0, 0]):

Point Elevation

(average)

Xn Yn

A 0 0 0

B 39.8 0 26.14

C 2.1 18.53 26.46

D 8.45 23.88 -3.78

1 -4.5 2.74 1.71

2 -12 3.34 23.75

3 -0.8 15.72 23.31

4 -4.65 14.84 1.30

The area and the perimeter of the field is:

A = 12.1 22 = 266.2 m2

P = 12.12 + 222 = 68.2 m

6. Contour MapElevation differences between lines: 4 cm


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7. Analysis1)Practical Analysis

This cartography practical activity is done in order to collect the

geometrical data on the field and then combine all the data gained into a

drawing plane by using a certain scale. After that, the contour map of the

area can be determined.

The first thing which is necessary to be done is to determine the

area which is wanted to be measured. In this practical activity, the GK

building is chosen as the area which is measured. After deciding the area,

draw a simple sketch which represents the area which is measured. This

sketch will assist the practical activity and will make the measurement

more organized. After that, set four points where the theodolite will be

erected. Note that, if possible, each set the theodolite should be able to aim

for all the four side of the field and three other theodolite measurement

points. All the positions also should possess different elevations; so that

the data which is gained can be represent the real situation on the field.

Then the theodolite is set at point A, where the benchmark is. After

shooting point B, 2, 1, 4 and D. The theodolite is then moved to point B. in

point B, the theodolite is meant to measure point A, 1, 2, 3 and C. note that

in point B, the terrain is high, so the theodolite setting took some extra

effort. After measuring from point B, the next step is moving the

theodolite to point C. In this point, the points which are measured are point

B, 2, 3 and D. Point 4 cannot be measured due to the presence of a tree

between point C and point 4. After doing the measurement at point C, the

theodolite is then moved to point D, where it measures point C, 3, 4, 1 andA. Note that every single point which is measured, the three crosshairs and

the horizontal angles should be noted.

After gaining all the data which is need to be calculated, measure

the real distances of the points which are measured before. This is done so

that the calculation can be simplified and the relative error can be

calculated.


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2)Result AnalysisFrom the data which is gained from the field, the contour map can

be drawn by using the elevation data. The distance in the contour map uses

the real distance which is gained by using the measuring tape, which is

done in order to ensure accuracy. In this contour map, it is revealed that in

respect to point A as the benchmark, the elevation of point B is 39.8 cm

higher, point C is 2.1 cm higher, point D is 8.45 cm higher, point 1 is 4.5

cm lower, point 2 is 12 cm lower, point 3 is 0.8 cm lower and point D is

4.65 cm lower. Note that the highest point measured on the field lies on

point B, with an elevation of 39.8 cm higher relative to point A. This result

is proven, since the area around point B is higher than its surrounding. At

point C and D, the distances between contour lines are a bit far, which

indicates that the plane is relatively flat. Note that all the points on the

field (point 1, 2, 3 and 4) are relatively lower than point A, which indicates

that settlement had happened on the field.

In this practical activity, the geometrical data which is gained are

plot on Autocad software. This makes the contouring drawing can be done

more easily. The software is also capable in calculating the area and the

parameter of the field, which are 266.6051 m2for area and 68.2734 m for

the parameter. This value resembles the area and the parameter which is

manually calculated (266.2 m2for the area and 68.2 m for the parameter).

By doing cartography, the coordinate of each points which are

measured can also be determined. The coordinates are in respect to point A

as the benchmark and line AB as the Y axis. Setting the AB as the Y axis

is done in order to simplify the calculation. The coordinates are: A(0;0),B(0;26.24), C(18.53;26.46), D(23.88;-3.78), 1(2.74;1.71), 2(3.34;23.75),

3(15.72;23.32) and 4(14.84;1.30). Note that these coordinates are gained

from the manual measurement data by using measuring tape, not the data

which is gained from the theodolite.


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3)Error AnalysisIn this practical activity, there are errors which had occurred. Some

of the errors are quite disturbing, but the data which is gained is still

considered usable. The relative error of this practical activity is ranging

from 0% to 30.7%. There are several errors which are able to be identified:

Personal ErrorThis type of error is caused by the practicants of the practical

activity. In this cartography surveying practical activity, the most

significant personal error was when determining the measuring

points of the theodolite. The practicants are not aware by the

presence of a tree between point C and 4, and the problem was

identified a little too late, so point 4 was not measured from point C.

The next personal error was when measuring the distances by

the tape, the tension given by the practicants was too large, which

may cause the tape to deform. Luckily, the deformation of the tape

may not be significant.

Another personal error which was done by the practicants

was when measuring point 2 from point B and when measuring point

1 from point A, the staff which was held was tilted, so the amount of

error of these two measurements was high.

Apparatus errorThe apparatus error which happened during the practical

activity can be considered as minimum. The only problem of theapparatus which may impair the measurement was the tape which

was used had been bended before, which shorten its measurement.

But this problem was solved by giving extra tension when measuring

distances with the tape


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Parallax errorThe parallax error is the error which caused by the

misreading of the apparatus. The parallax error that may happen

during this practical activity was that the theodolite was not read

precisely, which may cause the data to be less accurate.

8. Conclusion By doing cartography and collecting geometrical data on the field,

the data can be expressed on a drawing plane with a certain scale.

From the height difference of the plane, the contour map can bedrawn.

By reading the contour map, it is known that the area around point Bis higher than the majority of the area.

The coordinates of each points can be determined [A(0;0),B(0;26.24), C(18.53;26.46), D(23.88;-3.78), 1(2.74;1.71),

2(3.34;23.75), 3(15.72;23.32) and 4(14.84;1.30).]

The area and the parameter of the GK field can be determined (area:266.6051 m

2

, parameter: 68.2734 m)

9. ReferencesSurveying Practical Assistant Team.Pedoman Praktikum Ilmu Ukur

Tanah. Laboratory of Surveying and Mapping, Faculty of Engineering,

University of Indonesia. Depok.


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10.Attachment

GK Field, seen from Point B

surveying practical report - cartography kevinly

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