and right in the notebook must correspond to leftand right in the field.Figure 14-20 shows field notes for cross-section levels taken on the first three stationsshown in figures 14-16 and 14-17. On the dataside, only the station and the HI need to be listed.On the remarks side, each entry consists of a pointelevation, written over the distance of the pointfrom the center line. The computed elevation,determined by subtracting the rod reading fromthe HI, is written in above as shown. Note thatthe rod reading at the center line is the 5.5-ftvertical distance from your line of sight to theground. Also, notice that the center-line elevationwritten in at each station. is the one obtained inthe profile level run. You obtain the HI for eachstation by simply adding together these twofigures.Double RoddingDouble rodding is a form of differentialleveling in which a continuous check is maintainedon the accuracy of the leveling procedure. It iscalled double rodding because it can be done mostconveniently by two rodmen. However, it ispossible to carry out the procedure using only onerodman.In double rodding, you determine the HI ateach setup point by backlights taken on twodifferent TPs. If no mistake or large error hasbeen made, the result will be two HIs that differslightly from each other. Elevations computed thisway will also differ slightly. In each case, theaverage is taken as the elevation.Figure 14-21 shows double-rodded level notesfor a run from one BM to another by way of threeFigure 14-21.-Sample field notes from double-rodded levels.14-20
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