1. INTRODUCTION TO GEOMATIC ENGINEERING
PAT 153 GEOMATIC
INTRODUCTION TO GEOMATIC ENGINEERING

2. WHAT IS GEOMATICS?
The term Geomatics is an acronym formed by “Geo” that means the Earth, while the term “matics” refers to the information.
Geomatics is a new term that formerly known as surveying.
Surveying must be define as an art to determine the relative positions of points on, beneath the surface of the earth with respect to each others, by measurements of horizontal and vertical distances, angles and directions.
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3. The purpose of surveying
Determine the dimensions and contours of any part of the earth’s surface
To prepare a map
Establish bounderies of the land
Measure area and volume
Select a suitable site for an engineering project
SURVEYING
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4. Classification of Survey
Based on accuracy desired
Based on purpose of survey
Based on place of survey
Based on instrument used

5. BASED ON ACCURACY DESIRED
Plane surveying
The curvature of earth is not taken into consideration. Thus it is treats as a flat plane.
The instrument is always leveled according to the center of the earth (gravity level/plumb bob).
Only appropriate for engineering projects on large scale such as factories, bridges, dams, location, construction for canals, highways, railways etc.)
Geodetic surveying
The curvature of the earth is taken into consideration.
Used for the area exceeding the 250 km2
Used mostly for national mapping programs/national boundaries.
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6. Based on Purpose of Survey
Engineering survey-provide sufficient data for the design of engineering projects.
Defence survey-critical application in the military
Geological survey-surface & subsurface surveying to determine the location of different minerals & rock types & types of gelogical structure
Geographical survey-preparation of geographical maps.

7. Mine survey-consists of topographic survey of mine property (tunnels, shafts, drifts)
Archaeological survey – unearth the relics of antiquity, civilisations, kingdoms, towns, villages etc
Route survey
Reconnaissance Survey
Data gathering
Geospatial data – distances, position and angles
Locate physical position- water boundaries, trees, roads, structure, property marker
Determination of difference in elevation (vertical distance)
Preliminary 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)

8. Based on place of survey
Land survey
Topographical survey – obtain data to make a map indicating inequalities of land surface
Cadastal survey=surveys made to plot the bounderies of fields, houses and property lines.
City survey-fixing, locating, improving property lines in the city
Hydrographic survey-Preliminary survey-underwater features to surface control points (shorelines, marine features, water depth)
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9. Underground survey-Preparation of underground plans, fixing the positions and directions of tunnels, shaft and drift.
Aerial survey-Preliminary and final survey using aerial photography and imagery.

10. Based on Instrument Used
Commonly used in field surveying are:
Chain survey
Traverse survey
Tacheometry
Levelling
Plane Tabling
Triangulation
Electromagnetic distance measurement (EDM) survey
Total station survey
Satellite based survey
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11. EAT 112 GEOMATICS ENGINEERING

12. EAT 112 GEOMATICS ENGINEERING

13. NEW TREND Global Positioning System (GPS)
Navigation and identify the coordinate of certain location.
Remote Sensing Technique
Using satellite image
Geographical Information System (GIS)
Computer technology used GIS for data analysis, storage and updating the database.
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14. PRINCIPLE OF SURVEYING
To work from whole to part
To locate a point by at least two measurement
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15. PRINCIPLE OF SURVEYING
To work from whole to part
To localize the errors and prevent their accumulation.

16. PRINCIPLE OF SURVEYING
To locate a point by at least two measurement
Two control points are selected and the distance between them is measured.
The line joining the control points is plotted.
The desired point can be plotted by making suitable measurement from control points.

17. ERRORS Sources of Error
Natural error – result from temperature, refraction, obstacles to measurement, magnetic declination. This error are beyond the control of surveyor. Can be contained within permissible limit by adopting precautionary measures.
Instrumental Error – Imperfect construction and adjustment of the instrument. Can be minimize by applying proper correction and selecting suitable field method.
Personal Error – arise from limitations of the human senses such as sight, touch and hearing.

18. ERRORS
Types of Error
Systematic Errors – occur from well-understood causes. Can be reduced by adopting suitable method.
Accidental Errors – errors due to a combination of causes and beyond the control of surveyor.

19. MISTAKE AND ERROR Mistake
Caused by the misunderstanding of the problem, carelessness or poor judgement.
Only can be corrected if discovered.
Error
Difference of the measured and true value of the quantity.
Mistakes can be avoided by being careful, whereas errors result from sources which can be minimized but not avoided.

20. PRECISION AND ACCURACY
Degree of finess and care with which any physical measurement is made.
Represent the repeatability of a measurement and is concerned with only random errors.
Accuracy
Degree of perfection obtained.
Overall estimate of errors, including systematic errors present in measurement.

21. PRECISION AND ACCURACY

22. Edited from original slide by Mdm. Liyana
THANK YOU
Edited from original slide by Mdm. Liyana