Earth Geopotential Model of 2008 – Global Mapper

The Earth Geopotential Model of 2008 (EGM08) is a global geoid model that transforms height values between the WGS84 ellipsoid and a geoid surface that is “closely associated” with mean sea level. The model data exist in a single binary file consisting of a 2.5-minute grid of elevation difference values between the two surfaces. The elevation differences at non-grid point locations are interpolated.

The "EGM08" vertical transform has the following parameters:

Parameter Name	Parameter String	Units
Path to Data File	path	String
Data File Name	file	String

The path parameter can either be fully qualified or relative to the location of the data source file in which it is defined. The path string should not end with a slash character.