PPT Slide
? GPS determines geodetic heights (geometric): h
? Leveling determines orthometric heights: H
? The above heights are related through the geoid height: N ? h = N + H ? dH = dh - dN
? Geoid: The equipotential surface of the Earth’s gravity field which best fits, in a least squares sense, global mean sea level
? NGS produces GEOID99, a geoid consistent with NAD 83 and NAVD88
Height Systems and the Geoid
http://www.grdl.noaa.gov/GEOID/