Tower Maps
AMSL "Above Mean Sea Level"
There are two interpretations of the definition of AMSL used within the wireless industry. Some interpret the AMSL to be the elevation of the base of the structure (tower or rooftop), where as others interpret this to be the elevation of the top of the structure relative the mean sea level. Tower Maps uses the later definition where the AMSL is the elevation of the top of the structure relative to mean sea level. Because of the different interpretations, Tower Maps uses AGL, AMSL and Ground Elevation from data providers and works to develop a consistent definition. When only one type of elevation data (AMSL or GROUND) is available from the site owner/manager, assumptions are made by Tower Maps regarding the providers interpretation. Either Ground or AMSL are then calculated from one another using AGL.
The values used in Tower Maps are in feet.
Calculating HAAT
HAAT is defined as "antenna height above average terrain"
See the FCC's online calculator.