Topographical density effects on the relationship between geoid and orthometric height

Abstract

This thesis investigates the influence of topographical density variations on the computation of geoid heights, rigorous orthometric heights, and their congruency with geodetic height, focusing on the geologically diverse Colorado region. Traditional geoid and orthometric height models often assume a constant topographic density of 2670 kg/m³, overlooking significant lateral variations in mass distribution. This study uses the UNB_TopoDens2v02 model, which models lateral density variations, to estimate the influence of density variation in geoid and orthometric height computations.

The results showed that the topographical density variations can cause discrepancies of up to +/-9 cm in geoid height and up to +/-15 cm in orthometric height. The influence of topographical density variation on their relationship does not entirely cancel each other and can reach as much as +/-7 cm. Thus, it is important to consider the topographical density to enhance the congruency between geoid, orthometric height, and geodetic height.