A Geoidal section in East Africa

Abstract

Astronomical observations were made over a loop through East Africa from 8 degrees South to 3 degrees North in the years 1967 to 1971 at existing trigonometrical stations in the survey networks. The work presented in this thesis covers twenty three stations in Tanzania from t~te in Ufipa to the Kenya border. Astro-geodetic deflections were computed to second order accuracy and the resulting deviations of the vertical were converted into the separation of the geoid from the spheroid of the New Arc Datum 1960. Conversions were made onto the European Datum 1950 and also the Tranet 8E Datum of Isiolo to link with previously published work by Bomford (1958) and Henry & Walker (1974). Anomalous deflections are discussed in terms of the physical causes - topographical and geological - and those considered to have been caused by the computation and the adjustment of the networks of the Arc and its loops in Tanzania.