Absolute and relative testing of gravimetric geoid models using Global Positioning System and orthometric height data

The verification of gravimetric geoid models on land is presented using co-located Global Positioning System (GPS) and orthometric heights. This is undertaken in an absolute sense, which also constrains the zero-degree term in the geoid, and in a relative sense, which indicates the appropriateness of the gravimetric geoid model for transforming GPS-derived ellipsoidal heights to the local vertical datum. Two computer programs are presented for these purposes, which can also be used for comparing other types of discrete and gridded data. A case study is used to illustrate the use of these approaches and software to validate gravimetric geoid models in Western Australia. (C) 2001 Elsevier Science Ltd. All rights reserved.