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TRAVERSE SURVEY - Coggle Diagram
TRAVERSE SURVEY
ANGLE OBSERVATION
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Vertical angle 
Why observe both faces?
By taking the mean of FL and FR horizontal circle readings the effect of systematic errors of the instrument is eliminated (collimation error)
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Two rounds are needed so that errors can be detected when angles are calculated, since each round is independent
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DISTANCE MESUREMENTS
Distances along slopes are measured in short horizontal segments. Skilled surveyors can achieve accuracies of up to one part in 10,000 (1 centimetre error for every 100 metres distance)
Sources of errors
Flaws in the tape itself, such as kinks
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To measure distances, land surveyors traditionally have used 100-foot (30m) long metal tapes that are graduated in hundredths of a foot (mm)
Steel Taping
In traversing work, distance simply means the horizontal distance between the traverse stations, i.e. length of the traverse legs
Since the 1980s, electronic distance measurement (EDM) devices have allowed surveyors to measure distances more accurately and more efficiently than they can with tapes
To measure the horizontal distance between two points, one surveyor uses an EDM instrument to emit an energy wave toward a reflector held by the second surveyor.
Because the wavelength of the energy beam is known precisely, the instrument can quickly calculate the distance as a function of the shape of the wave as it returns from the reflector
Typical accuracies up to one part in 20,000, twice as accurate as taping
The required horizontal distance is computed from the slope distance and vertical angle measured. Total stations normally have this facility built-in.
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INTRODUCTION
Traverse simply refers to a survey method of providing a series of stations whose positions (or coordinates) are obtained from bearing and distance observations of adjacent stations
Coordinates of any station can be determined by observing its bearings and distances from an adjacent station whose coordinates are already known
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Bearings are normally measured in the range 0° to 360° from the north direction, and is commonly termed as the whole circle bearings (wcb)
There are instances where bearings are written with respect to the north-south direction, known as quadrant bearings. Example : N45°E, S60°W, etc.
By observing the bearings and distances of adjacent stations, a series of coordinated points would be created
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TRAVERSE MISCLOSURE
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In practice, due to random errors
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Supposing the total traverse distance is ∑S metres, then the linear misclosure is e : ∑S or 1 : ( ∑S / e )
For engineering applications, an accuracy of 1 : 4,000 (second class) is used as the minimum
ERRORS IN TRAVERSING
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Traverse misclosures
There are no gross errors, only errors that have to be dealt with are random errors
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Traverse with Angular Angular Error Only
Traverse with Distance Error Only
Traverse with Both Angular and Distance Errors
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COORDINATE SYSTEMS
Rectangular cartesian system
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Polar coordinate system
LATITUDE & DEPARTURE
The bearing and distance measured for each traverse leg are then used to compute latitudes and departures (or sometimes called as coordinate differences)
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In essence, latitude refers to the difference in northings of two traverse stations whereas departure denotes their difference in eastings
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ANGULAR MISCLOSURE
In engineering applications, the standard set for second class traverse is adopted i.e. maximum angular misclosure is ±2’ 30”
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TRAVERSING FIELDWORK
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Reconnaissance
Station marking, identify location, intervisibility
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