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Practical Principle of Surveying Syllabus (Main Content) • Basic Principles • Distance Measurement and Chain Surveying • Distance Measuring Methods-Taping 1-direct methods 2-Indirect method *Length& Distance Measuring. Two principles of measuring distance 1) It takes two points, to form a line. 2) The shortest distance between two points, is straight line. Methods of Measuring Distance 5 1. Direct Methods of Measuring Distances 2. Indirect Methods of Measuring Distances Indirect Methods of Measuring Distances 1-Theodolite instrument )Stadia(, 2-Tachometry 3-sub-tense method. The methods are Subtence bar, 4-Electronic distance mmeasurement (EDM) 5-Total Station, (TS) 6- G P S . Electronic Distance Measurement (EDM) 7 accurately measure distance by measuring the time it takes a laser or other ray to travel from the EDM to a prism and back. Surveying practical Length and distance measurement Observation & measurement Methods of measuring Length and distances 1-direct methods 2-Indirect method )Direct methods) 1-pacing 2-measuring wheel 3-chain 4-tape 5-car odometer Direct Methods of Measuring Distances • Pacing • Measuring distance by counting steps (paces). • Distance is calculated by multiplying the number of paces by the individuals pace factor(usually every step one meter ). • Advantages • Simple • Low tech • No specialized equipment 10 • Disadvantages  Topography affects accuracy  Requires practice to take a consistent pace.  Must be able to traverse the distance.. • With practice, accuracy is about 2% of distance paced Car Odometer • measuring the distance passed over by any wheeled vehicle • An instrument attached to the wheel of a vehicle, to measure the distance traversed. Error 1% of distance • An odometer wheel is a wheel which uses an odometer to count the rotations of the wheel. Use for long rout distance like (highway, railway ) • Advantages – Easy to use – Low tech • Disadvantages – Accuracy is influenced by surface conditions. – Must be able to traverse distance. Error 1% of distance -The Chain. -Measuring tape -Type of Tape. -Tape Marking and Graduation. -Tape Zero Point. Equipment for Taping. -• Range Pole (Range Rod). • Survey Pegs • Plumb Bob *Processes in taping Surveying. • Level Ground • Uniformly Sloping Ground • Uneven Ground -Slope distance. -Slope correction… Step Taping… 1-Report Number ( 1 ) 2-Report nameLength and distance measurement .Perpendiculars off sets Erecting and Dropping . 3-Object A-B Are two fixed points to measure the horizontal distance between these two point A and B .To Erecting And Dropping lines for known point . Erecting and dropping perpendiculars (or offsets): • A- Erecting perpendiculars • 1-Pythagoras • 2-Length of Tape 3- Erecting by optical square Dropping Perpendiculars 1-Radius . 2-Short length distance. 3-Dropping by optical square Prepared by: Asst. Prof. Salar K.Hussein Mr. Kamal Y.Abdullah Erbil Polytechnic University Technical Engineering CollegeRead less