Geoidmodeller

Geoidmodeller refers to software tools, libraries, or methodological frameworks designed to construct geoid models, which represent the Earth's mean sea level as an equipotential surface of the gravity field. A geoidmodeller typically integrates gravity data of varying sources to produce geoid undulations, or height anomalies, over a region or globally. The resulting geoid model enables the conversion between ellipsoidal heights from GNSS measurements and orthometric heights used in height reference systems.

Inputs and data sources commonly used by a geoidmodeller include satellite gravity models (such as global gravity field models), airborne and marine gravity surveys, and land-based gravimetric measurements. Topographic and bathymetric corrections, as well as gravity anomalies, are processed and integrated. Geoidmodellers may also incorporate auxiliary information from GNSS leveling campaigns to improve local consistency.

Modeling approaches span gravimetric methods, integral formulations, and stochastic estimation techniques. Typical methods include Stokes-Helmert type computations, least-squares collocation, kriging, and spline or polynomial fitting, often combined with regional refinements. Some implementations support ocean tidal and sea surface loading corrections to maintain coherence with oceanographic data. Output formats usually provide geoid height values on regular grids, which can be interpolated for user applications.

Applications of geoidmodellers include surveying and mapping, civil engineering projects, datum realization and transformation, and GNSS height unification with national height systems. The quality of a geoid model depends on the density and accuracy of gravity data, the resolution of the gravity field model, and the effectiveness of coastal and marine data handling.