Intro & Distance

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ERT 247

GEOMATICS ENGINEERING

SITI KAMARIAH MD SAAT

LECTURER

SCHOOL OF BIOPROCESS ENGINEERING

[email protected]


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COURSE OBJECTIVES

CO1: Ability to APPLY concepts andprinciples of geodetics and PERFORMsurveying tasks and procedures.

CO2: Ability to COLLECT and ANALYZE data

from various types of geodetics surveying.

CO3: Ability to ANALYZE remote sensingprocess and component and DEDUCE datainterpretation analysis.

CO4: Ability to ANALYZE the concept,component and application of precisionfarming in agriculture and analysis the geo-reference using spatial information

technologies (GIS and GPS)


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TEXT BOOK

Kavanagh,B.(2009) SurveyingPrinciples and Applications 8thEdition, Pearson Education,

Inc.,Upper Saddle River, NewJersey

Lillesand, T.M., Kiefer,R.W and

Chipman, J.W. (2007), RemoteSensing and Image Interpretations,John Wiley and Sons, New York


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REFERENCE BOOKS

McCormack, J. (2004), Surveying,5th Ed., John Wiley and Sons, NewYork, NY.

Uren,J and Price, W.F., (2006)Surveying for Engineers, 4thEd.,Palgrave Macmillan,N.Y


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TOPICS COVERED

PART 1

SURVEYING

PART 2

REMOTE

SENSING &

GIS


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PART 1-SURVEYING

DISTANCE MEASUREMENT

LEVELLING

ANGLE AND MEASUREMENTTRAVERSE

ELECTRONIC DISTANCE

MEASUREMENT (EDM)TACHEOMETRY

CUT AND FILL


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PART 2-REMOTE SENSING &GISGEOGRAPHICAL POSITIONING SYSTEM

(GPS)

REMOTE SENSING ELECTROMAGNETIC RADIATION

SATELLITE AND SENSOR

MICROWAVE & LIDAR SENSING

IMAGE INTERPRETATION

GEOGRAPHICAL INFORMATIONSYSTEM (GIS) GEOGRAPHIC DATA & DATABASE

SPATIAL DATA


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WHAT IS GEOMATICS?

The term Geomaticsis an acronymformed by Geo that means the

Earth, while the term matics refers

to the information.Defined as a science, art and

technology of determining the

relative position above, on orbeneath the earths surface, or

establishing such points(Ghilani and

Wolf,2008)


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WHAT IS GEOMATICS?

The mathematics of the earth; thescience of the collection, analysis,and interpretation of data,

especially instrumental data,relating to the earth's surface.(Oxford English Dictionary)

Geomatics is a new termincorporating the older field ofsurveying.


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WHAT IS SURVEYING?

The art and science of measuringangles, distances and positions(northing, easting and elevation),

on or near the surface of the earth.


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APPLICATION OFSURVEYINGThe location of ground features are

measured to prepare a map or planof the area.

Design features, shown on a mapor plan, are located in the field bydistance, angle and/or positioning

measurements.


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TopographicalMap


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Types of Survey

Plane surveying is thattype of surveying inwhich the surface of theearth is considered to bea plane for all X and Ydimensions.

Geodetic surveying is that

type of surveying inwhich the earth isconsidered to beellipsoidal for X and Y

dimensions.


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Classes of Surveys

Preliminary survey Data gathering Geospatial data distances, position and angles Locate physical position- water boundaries,

trees, roads, structure, property marker

Determination of difference in elevation (verticaldistance)

Layout survey Marking on the ground wood stakes, iron bars,

concrete monuments, nails, spikes, etc

Property lines, engineering works (roads,pipelines, bridges) and construction surveying

Control survey Use as reference both preliminary and layout

survey. Horizontal and Vertical control (benchmarks)


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What is benchmarks?

Benchmarks Permanent Pointswhose elevations above mean sea

level have been carefully determined


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SurveyingFields

Topographic surveys

Preliminary survey-natural & manmade

surface features of anarea.

Hydrographic surveys

Preliminary survey-underwater features tosurface control points(shorelines, marinefeatures, water depth)

Route surveys

Preliminary, layout andcontrol survey fornarrow-long strip of land(highway, railroads,electric transmission

lines, channel)


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SurveyingFields

Property surveys Preliminary, layout and

control survey involve indetermine boundary

location/laying out newproperty boundary

Construction surveys Layout survey for

engineering works

Final (as-built) surveys Similar to preliminary

survey Provide final record of

constructed features hasproceed according to

design plan Aerial surveys

Preliminary and final surveyusing aerial photographyand imagery. Use of digital

camera, lidar, radar


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SurveyingInstrumentationCommonly used in field surveying

are:

1. Satellite Positioning Receiver

(GPS)

2. Total Station

3. Level & Rod

4. Theodolite

5. Steel Tape


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SurveyingInstrumentation (Pic)


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Geomatics Data ModelShowing the collection, processing, analysis, design and plotting

the geodata

Collection

Process

Analysis

Collection

PlottingPlotting Plotting


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Surveying References

Geographic reference Earth reference system denoted by

geographic lines of latitude and longitude Latitude - run east/west (parallel to equator)

Longitude run north/south converging at thepole Use in navigation and geodesy

Grid reference Grid system for a states/province Ease of calculation (plane geometry) and

availability datum for large area (thousandmiles)


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Surveying References

Legal reference Township subdivide by section and ranges

(lot) that unique numbered

Vertical reference Can be reference to any datum. Datum most

used are Mean Sea Level (MSL). MSL is assigned an elevation of 0 ft or 0 meter.


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Geographical Coordinates

TOPIC 2


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TOPIC 2

LINEARMEASUREMENT(TAPING)

At the end of lecture, student are ableto:

APPLY principle of taping and tapingmethodology


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Introduction

One of the fundamentals of surveying isthe need to measure distance.

Distances are not necessarily linear,

especially if they occur on the sphericalearth.

In the present subject we will deal withdistances in Euclidean (geometric)

space, which we can consider a straightline from one point or feature to another.


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Distance Measurements

Distance between two points can behorizontally, slope or vertically recorded infeet/meters.

Horizontal and slope distance can be measured

using fibreglass tape/steel tape/using electronicdistance measuring device.

Vertical distance can be measured using a tape,as in construction work, with a surveyors level

and levelling rod.


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Three types of distance

Vertical

Horizontal

Slope


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Slope, Vertical andHorizontal Distances


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Units of Measurement

Linear Measurement Metric Unit

1 kilometer 1000 meter

1 meter 100 centimeter

1 centimeter 10 milimeter1 decimeter 10 centimeter

1 hectare (ha) 10,000 m2

1 square kilometer 1,000,000 m2

100 hectares

1 acres (ac) 100 m2


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Units of Measurement

Foot to metric conversion

1 mile = 5.280 ft

1 foot = 12 inches

1 ft 0.3048 m

1 inch 25.4 mm1 ha 2.471 ac

0.62137 miles 1 km


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Accuracy & Precision

Accuracy The relationship between the value of

measurement and and the true value

Degree of perfection obtained in

measurement


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Precision Refinement of the measuring process and

ability to repeat the same measurement withconsistency small variation in the

measurements (no large discrepancies) The closeness of one measurement to

another

If a quantity is measured several times andthe values obtained are very closed to eachother, the precision is said to be high.


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Types of errors

Blunders

mistakes and grosserrors

Systematic errors repeated size and sign

affect accuracy

Random errors small and usually

undetectable (noise)

affect precision

These error

types apply

to anymeasuremen

t technique

used in

surveying


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Errors

No measurement can be free fromerror.

For calculating error, the true valuedetermined statistically afterrepeated measurement.


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Errors

Systematic errorsare those errorswhose magnitude and algebraic signcan be determined.

Eg: Effect of temperature, wind andmagneticvariation on steel tape


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Errors

Random errorsare associated withthe skill and vigilance (observation)of the surveyor.

No surveyor/human being hasperfect sense of sight and touch.


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Errors

To reduce mistakes:

All survey measurement aresuspect until verified (repeating

the measurement/ trigonometricanalysis)

Every measurement is

immediately checked/repeated.


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Distance measuringequipment and typical

accuracies

Pacing (1:50 to 1:100)

Optical range finder (1:50 to 1:150)Trundle wheel equipped with

odometer(1:200)

Stadia tacheometry (1:500)


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Distance measuringequipment and typical

accuraciesSubtense bar (1:3000)

Taping or chaining (1:5000 to10,000)

Electronic distance measurement(EDM) (1:50,000) +- (1mm+1ppm) to(10mm+5ppm)

Di t i


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Distance measuringequipment


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Some things to note

Equipment is fairly cheap (except EDM)

Equipment is easy to maintain andadjust ()

Distances are easy to measure Very accurate results can be achieved

Measurement line needs to beunobstructed

Errors occur and need to be managed orminimised


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Taping (or chaining)

Taping is applied to measurement witha steel tape or synthetic tape (plastic orfiberglass).

All standard in lengths 100 m, 50m, 30 m, 20 m.

It is fairly quick, easy and cheap, andhence is the most common form of

distance measurement.


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Taping (or chaining)

Unfortunately, taping is prone to errorsand mistakes.

For high accuracy, steel tape should beused which is graduated in mm and

calibrated under standard temp (20degree) and tension (5kg). Be careful,easily break.

Synthetic tape is more flexible graduated

in 10mm


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Taping


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Taping Accessories

Plumb bob

Hand level

Clinometer

Range pole

Tension handle


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Accessories


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Hand Level


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Abney Clinometer

Use of a Steel Tape and


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Use of a Steel Tape andPlumb Bob

Horizontal Taping Using a


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Horizontal Taping Using aPlumb Bob

Horizontal Taping Using


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Horizontal Taping UsingPlumb Bobs


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Taping procedures

Tape must always be straight

Tape must not be twisted

Use chaining arrows for intermediate

points

Tape horizontally if possible

Tape on the ground if possible

Slope taping needs to be reducedCatenary taping requires correction

Step taping suits some applications


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Tape must be straight

obstruction

measured distancerequired distance


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Length AB = 4 x Full tape distance + 1 Short section

REMEMBER ! It works only on smooth ground or uniform slope surfaces


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Use chaining arrows

measured distancerequired distance


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Taping Correction

Systematic TapingErrors

Random TapingError

1. Slope 1. Slope

2. Erroneous length 2. Temperature

3. Temperature 3. Tension and Sag

4. Tension & Sag 4. Alignment

5. Marking &Plumbing

Typical taping error:


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Taping Corrections

Forsynthetic tapes, only ErroneousTape Length and Slope corrections willbe applied

The best accuracy that can be achieved isthe order of 1:1000


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Taping Corrections

When using steel tapes, if only ErroneousTape Length and slope corrections are

considered, the best possible accuracy that

can be obtained in the range 1:5000.

If tension and temperature are added into

consideration, accuracy can be increased to

better than 1:10000 ~ 1: 20000

Sag only applies if tape is supported only atends

Standard Conditions for


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Standard Conditions forSteel Tape Use (Metric)

30.000 m tape

- Temperature = 20 C

- Tape fully supported- Tension = 50 Newtons (11.24lbs)

Specifications for 1:5 000


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Specifications for 1:5,000Accuracy


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Erroneous Tape Length

Tape has a nominal length under certainconditions, a tape stretches with time.

Standardisation needs to be carried out

frequently by using reference tape orbaseline.

correctionTotal

lengthper tapecorrection

'

L'

L

where

lengthassumed

lengthmeasuredxLL


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Tension Correction

A tape is a given length when pulledwith a certain tension. If the tensionchanges then so does the tape length.

AELPsPCp )(

Where

Cp= correction due to tension per tape length

P= applied tension

Ps=Satndard tension

A = Cross Sectional Area

E= Average modulus of elasticity of steel tape

L = length of tape under consideration


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Sag Correction

Where

Cs= sag correction per tape length

W=weight of tapeP=Applied tension

L= Length of tape

2

2

24P

LWCs

If a tape has been standardized while fully supported

and is being used without full support, an error called

sag occur.


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Temperature correction

Ct = kTL

where :

Ct is the corrected distance

L is the measured distance

c = 1.15 x 10-5 m/oC (for a steel

band)T = Tactual - Tstandard


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Slope correction

For example :

s = 30.589 m

q = 2.5o

H = 1.334 m

then

h = 30.589 cos(2.5)

h = 30.560 mTo calculate the horizontal distance :

h = s cosq or h = (s2 - H2)1/2

q

horizontal distance = h

H

Or.

s = 30.589 m

H = 1.334 m

then

h = (30.5892 - 1.3342)1/2

h = 30.560 m


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Step taping

required (horizontal) distance


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Catenary taping

measured distancerequired distancerequired distance

Catenary


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Catenary(sag) error

A suspended tape will measure toolong

where :

M is the mass per unit length (0.011

kg/metre)g is gravity (9.8 metre/sec2)

T is the tension (50 Newton)

is the slope angle

2

2

32

cos

T24

L)Mg(LL


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Exercise


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Intro & Distance