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surveying iii (topographic and geodetic surveys) - Modern Prepper

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. Sight along the tops of both of the 50-meter posts <strong>and</strong> locate <strong>and</strong> drive a fiducial nail horizontallyinto the face of the intermediate stake so that the nail is on line with the tops of the posts. These nailsserve as intermediate supports between 50-meter posts during measurements. Nail a strip of copper orzinc on top of the 50-meter posts to provide a suitable surface on which to mark the tape lengths.c. Ideal conditions may not be present in actual field practice. For example, at ravines <strong>and</strong> streams,it may be necessary to begin a tape length by placing a stake on the edge of a bank. If this stake is lessthan half a tape length from the previous tape end post, the number of which is 16, number thefractional-length post 16 setup. Number the next terminal post 17. If the fractional-length post is morethan half a tape length from the next preceding tape end post, drive a 2- by 4-inch stake at the halfwaymark <strong>and</strong> number it 16 1/2 setup. Following this system will prevent uncertainty in the interpretation ofthe records.d. With the reconnaissance made, the signal towers erected, <strong>and</strong> the station stakes set, it is time tomeasure the exact length of the baseline. Before doing this, run a line of levels over the line todetermine the relative elevations of all 50-meter posts <strong>and</strong> broken-grade stakes.3-9. Level the Baseline. The leveling sheet (DA Form 4446) in Figure 3-2 shows the level record whenusing a rod graduated in meters on one side <strong>and</strong> feet on the other. When using such a rod, run the levelsonly in one direction, but read both sides of the rod at each rod point. Record the reading in meters asthe forward running <strong>and</strong> the reading in feet as the backward running. If the rod is graduated on only oneside, make both forward <strong>and</strong> backward runnings. Be extremely careful to obtain readings on all brokengrades <strong>and</strong> partial tape lengths, <strong>and</strong> plainly indicate the readings in the record. Mark the columns aseither meters or feet, as applicable. Pay particular attention to the column headings in the level notes.Each item will eventually enter into the final calculations for the true length of the baseline. Refer toFigure 3-2 <strong>and</strong> the following information for required detailed column information:EN0593 3-8

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