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The error of closure is 0.015 ft. By substituting these values into the above formula, the correction is as follows: Since the observed elevation of the closing BM is greater than its known elevation, the adjustments are subtracted from the intermediate BMs.
In this example, the average measured value is (123.25 + 123.19) , 2 = 123.22 m. The error of closure would be 123.30 - 123.22 = 0.08 m. Yet another way to determine closure, from a series of independent measurements of the same quantity, is to use the maximum anticipated error.
That formula, En = + Evh, states that the probable total error after more than one operation is the probable error in one operation multiplied by the square root of the number of operations.
Unfortunately even with the best equipment and practices, this is impossible and so you will need to calculate the error of closure in the X (east or departure) and Y (north or latitude) directions. The error of closure is computed as: Cx = "#X Cy = "#Y Where: Cx = total closure distance of X and Cy = total closure distance of Y.
You close or balance a traverse by distributing the linear error of closure (one within the allowable maximum, of course) over the traverse. There are several methods of doing this, but the one most generally applied is based on the so-called compass rule.
To compute the traverse closure accuracy ratio, divide the square root of the sum of the squares of the latitude and departure misclosures by the sum of the horizontal distances of the traverse. To balance the angles of a traverse, distribute the angular error of closure equally to all the traverse angles.
In traverse survey, latitude and departure, checks in a closed traverse, closing error, relative precision, bowditch’s rule, transit rule are details discuss.
