Figure 7-5.–Adjustmmt of level nets.For circuit BCDEB, the error of closure is –0.40 ft.This is distributed among the lines in proportion to theirlengths. Thus, for the line BC, the correction is(Notice that the sign is opposite to that of the error ofclosure.) The correction of +0.07 ft is entered on the firstline of the column headed CORR and is added to thedifference in elevation (10.94 + 0.07 = +11.01). Thatsum is entered on the first line under the heading CORRDE (corrected difference in elevation). The sameprocedure is followed for the remaining lines CD, DE,and EB of circuit BCDEB.The sum of the corrections must have the oppositesign and be equal to the error of closure. The algebraicsum of the corrected differences in elevation must equalzero. The lines in circuit AEDA are corrected in the samemanner as BCDEB, except that the corrected value ofED (+27.08 instead of +27.15) is used. The lines ofEABE are corrected using the corrected value of EA(+17.97 instead of +17.91) and BE (+5.13 instead of+5.23). In the column Cycle II, the procedure of CycleI is repeated. You should always list the latest correctedvalue from previously adjusted circuits beforecomputing the new error of closure. The cycles arecontinued until the corrections become zero. Thesequence in which the circuits are taken is immaterial aslong as they are repeated in the same order for eachcycle. Computations may be based on corrections ratherthan differences in elevation.TRAVERSE COMPUTATIONSTraverse operations are conducted for mapping; forlarge construction projects, such as a military post or anFigure 7-6.—Computations required to balance the level net.7-7
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