Every height in Waveshed — eye height and target height in LOS, or TX and RX height in RF — has an AGL / AMSL toggle. They answer “height above what?”.
Each height has its own AGL / AMSL toggle.
AGL — above ground level
Metres above the terrain at that point. This is what you usually want: eye level (≈1.7 m), an antenna’s
height on its mast, or a building’s height. If the ground there is 1500 m and you enter 10 m AGL, the
antenna sits at 1510 m absolute.
AMSL — above mean sea level
An absolute altitude, independent of the ground. Use it when you know the absolute figure — a summit
elevation, or an aircraft/drone altitude. Waveshed shows the ground elevation at your point, and when you
enter an AMSL height it shows the equivalent height above ground, so the two are easy to reconcile.
Tip. When in doubt, use AGL — “how high above
the ground is the antenna/eye” is the natural way to think about most setups.
