Geoid Models

The Geographic Calculator supports a number of regional geoid models. These models are based on data tables containing differences between the ellipsoid and the geoid model for a given area. Please be aware that these models are not exact Mean Sea Level values, but are approximations of Mean Sea Level.

Supported vertical transformation types are available for many localities around the world. If the grid files for a particular geoid are not available for download through the Datasource dialogs, please contact Blue Marble Geographics' technical support for information on the availability of a particular grid.

All transformations show the default type of interpolation used for that method on the definition for that geoid. Newly created geoids will start with the default method selected.