1. Likewise, spirit levels will always be parallel to the geoid . 2. Spherical harmonics are often used to approximate the shape of the geoid . 3. Geoid measures help thus to understand the internal structure of the planet.4. Instead, the geoid of the earth is described by many ellipsoids. 5. Dynamic heights are usually chosen so that zero corresponds to the geoid . 6. EGM96 differs from the original WGS 84 geoid , referred to as EGM84. 7. VDs are used in astro-geodetic levelling, a geoid determination technique. 8. The geoid is essentially the figure of the Earth abstracted from its topographical features. 9. As geoid knowledge accumulates, one may expect use of GPS heighting to spread. 10. The geoid is a particular equipotential surface, and is somewhat involved to compute.
