Geodetic survey control points must be remarkably stable due to the very intent of establishing geodetic control. All monuments are subject to the effects of geologic and soil activity. Vertical control points are particularly vulnerable because this activity results in vertical movements much more so than horizontal motion. In addition to natural disturbances,damage inflicted by mankind is a critical problem in monumentation. This manual explains how and where to set bench marks for maximum stability and calls attention to the factors that affect vertical instability.
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