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Carrying and Setting Up a LevelAlways carry it in the container,Screw the head snugly on the tripod.For bull eye’s bubble, alternately turn one screw and then the other two.On side-hill setups, place one leg on the uphill side and other two on the down hill side.Use hand level to check for proper height of the setup before precisely leveling the instrument.
Duties of a RodpersonFor correct reading, the level rod must be held plumb.Using rod level, when the bull’s-eye bubble is centered the rod is plumbed in both directions.When a rod level is not available waving the rod is one of the procedure.
PrecisionFor example, on a simple construction survey, an allowable misclosure of
where n is the number of setups.The Federal Geodetic Control Subcommittee (FGCS) USA recommends allowable misclosures
where C is the allowable loop misclossure, in millimeters, m is a constant, and K is the total length leveled in kilometers (for loops – circuits that begin and end on the same BM, K is total perimeter distance.
MistakesImproper use of a long rod,Holding a rod in different places for the plus and minus sights on a turning point.Reading a foot too high.Waving a flat bottom rod while holding it on a flat surfaceRecording notesTouching tripod or instrument during reading process.
Reducing Errors and Eliminating MistakesErrors in running levels are reduced by
Carefully adjusting and manipulating both instrument and rod.Establishing standard filed methods and routines.The following routines prevent most large errors or quickly disclose mistakes:
Checking the bubble before and after each reading (if an automatic level is not being used).Using a rod level.Keeping the horizontal lengths of plus and minus sights equal.Making the usual field-book arithmetic checks