The Columbus geoid

Abstract

The author gives a summary of the preparatory work, collection of the needed gravity material, reduction method used, the gravity anomaly maps of different types needed, and the details of the method of computation of the geoid. Using the available materials, 6679 squares of 1° X 1°, four times larger than was available in 1928, several new gravity formulas have been derived. The globe was divided into 36 longitude zones of 10°. A diagram and table give an idea of the corrections to the International Gravity Formula obtained from different zones. When all gravity observations made in the oceans are available, the equatorial value of gravity may get a small negative correction. The geoid in Europe, where Tanni already had rather good material, will remain nearly unchanged, but the geoid in America, in the Atlantic, and in India changes materially as a result of additional gravity observations, particularly at sea. Sketches of portions of the geoid are given. The astro‐geodetically computed geoid of Europe, by Bomford, is compared with the Columbus geoid.