height of instrument
Also found in: Acronyms.
height of instrument[′hīt əv ′in·strə·mənt]
In survey leveling, the vertical height of the line of collimation of the instrument over the station above which it is centered, or above a specified datum level.
In spirit leveling, the vertical distance from datum to line of sight of the instrument.
In stadia leveling the height of center of transit above the station stake.
In differential leveling, the elevation of the line of sight of the telescope when the instrument is leveled.