ADAPTATION OF THE GLOBAL GEOID MODEL EGM2008 ON CAMPANIA REGION (ITALY) BASED ON GEODETIC NETWORK POINTS

Abstract. The knowledge of the geoid undulation, height relative to a given ellipsoid reference, is fundamental transform ellipsoidal heights into orthometric heights. Global undulation models developed from satellite gravity measurements appropriately integrated with other data, are free accessible in internet, but their accuracy may be inadequate for specific applications. Earth Gravitational Model 2008 (EGM2008) one those: usually available grid form 2.5’ × (a geotif by Agisoft resolution 1’ 1’), it defines difference between WGS84 and mean sea level, some areas discrepancies these undulations local correspondent measured values on order various decimetres. For consequence, more accurate necessary. This article aims determine model suitable Campania Region (Italy), starting global EGM2008 (1’ 1’) that locally adjusted using geodetic network points (GNPs) GIS interpolation functions. Three different datasets considered including respectively 20, 40 60 GNPs three deterministic interpolators applied way generate grids: Inverse Distance Weight (IDW), Polynomial 1st (GP1), 2nd (GP2). resultant 9 tested 20 additional GNPs. experiments demonstrate can produced little area adapting means GNPs: obtained GP2 GNPs, most one, fits data ±3.2 cm root square error (RMSE).