Bathymetric data over lake areas are not included in previous NGS (National Geodetic
Survey) geoid model computations. Mean lake surfaces are used as the bare rock surface
during the modeling. This approximation treats the water body as rocks with the same size,
and causes errors that can be avoided. This study uses the bathymetric model to rigorously
compute the volume of water bodies instead of treating them as rocks, during geoid
modeling. To make fair comparisons and show the effects clearly, three sets of geoid models …