Height above ground level
HEIGHT MEASURED WITH RESPECT TO THE UNDERLYING GROUND SURFACE
Above Ground Level; Above ground level; Metres above ground level; Altitude above ground level; Height Above Ground Level
In aviation, atmospheric sciences and broadcasting, a height above ground level (AGL or HAGL) is a height measured with respect to the underlying ground surface. This is as opposed to height above mean sea level (AMSL or HAMSL), height above ellipsoid (HAE, as reported by a GPS receiver), or height above average terrain (AAT or HAAT, in broadcast engineering).