The United States geoid models relate the difference between the GRS80 ellipsoid and the NAVD88 vertical datum.
The "GEOID03" vertical transform has the following parameters:
Parameter Name |
Parameter String |
Units |
Path to directory containing grid files |
path |
String |
File extension of grid files |
extension |
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.