Setting up a geoid model in Cotonou

Abstract

The reference considered for altimetry measurements in Benin would be accurate only if the geoid of all French West Africa was the same as the geoid of Benin. But it is important to know precisely, the geoid of the place to determine the altitude. Republic of Benin does not yet have a national model of geoid. The definition and modeling of the ge imperative to facilitate the task to the actors of measurement and localization. To better determine the position of the poin to be observed, a theoretical grid of 1km was applied throughout the territory of the Commune of Cotonou and le choice of a hundred points. Raw observational data was calculated using PrepaComp software (PrepaComp: Software for switching from Leica GSI format to OBS format) developed by IGN The geometric geoid determined on the leveled points and the gravitational world geoid will result in two different reference planes. The gap between these two planes is called the trend. The undulation N of the geometric geoid at each of these points has been determined. So the geoid Nglc_2017 (Rippling of the local geoid of Cotonou) determined is an accuracy of two centimeters (2cm)