G99SSS is a gravimetric geoid that served as the basis for GEOID99 within the conterminous United States only.
G99SSS was determined from more than 3 million gravity points and several high resolution elevation models.
Its heights range from a low of -52.56 meters (magenta) in the Atlantic Ocean to a high of 3.08 meters (red) in the Labrador Strait.
