Tiêu đề CEP233 - M3 - Measurement of Horizontal Distances.pdf ✅

2 of 7 CEP233 | FUNDAMENTALS OF SURVEYING method somehow becomes sufficiently accurate for small-scale mapping, for locating details and traversing with the plane table, and in reconnaissance surveys. Under average conditions, a good pacer will have little difficulty in pacing distances with a relative precision of 1/200. In using this method, it is necessary to first determine the estimated length of one’s pace, referred to as the pace factor, through naturally walking in a specified straight line so as to increase its accuracy. One method in determining one’s pace is to determine the average length of an individual’s normal step. Another method is to adjust one’s pace to some predetermined length, such as 1 meter. It is advisable to do this in at least five or more trials in order to determine the average number of paces. The pace factor is then determined by dividing the known distance by the average number of paces required to traverse it and is expressed in meters per pace. Here are some of the mechanical counter and/or electronic devices an individual may use as he undergoes pacing: SAMPLE PROBLEMS: E3-1 DISTANCE BY PACING. A 45-m course, AB, on level ground was paced by a surveyor for the purpose of determining his pace factor. The number of paces for each trial taken are shown in the accompanying tabulation. Trial Line Taped Distance No. of Paces Mean 1 AB 45.0 m 50 52 2 BA 53 3 AB 51 4 BA 53 5 AB 52 6 BA 53 Requirements: a) Determine his pace factor b) If the surveyor then took 771, 770, 768, 770, 772, and 769 paces in walking an unknown distance CD, what is the length of the line? c) Assuming that the taped length of line CD is 667.0 m, determine the relative precision of the measurement performed. Solution: a) Determine Pace Factor: Mean = ∑ No. of Paces n = 50 + 53 + 51 + 53 + 52 + 53 6 = 312 paces 6 = 52 paces Pace Factor = L Mean = 45 m 52 paces = 0. 865 m/pace b) Determine Pace Distance: Mean = ∑ No. of Paces n = 771 + 770 + 768 + 770 + 772 + 769 6 = 4620 paces 6 = 770 paces Paced Distance = Mean(Pace Factor) = 770 paces (0.865 m pace) = 666. 1 m c) Determine Relative Precision: Taped Distance = TD = 667.0 m Paced Distance = PD = 666.1 m