caa a22 4500 475737628 CHVBK 20180406123451.0 cr unu---uuuuu 170329e20000901xx s 000 0 eng 10.1007/s001900000107 doi (NATIONALLICENCE)springer-10.1007/s001900000107 How to handle topography in practical geoid determination: three examples [Elektronische Daten] [O. C. D. Omang, R. Forsberg] Abstract.:  Three different methods of handling topography in geoid determination were investigated. The first two methods employ the residual terrain model (RTM) remove-restore technique, yielding the quasigeoid, whereas the third method uses the classical Helmert condensation method, yielding the geoid. All three methods were used with the geopotential model Earth Gravity Model (1996) (EGM96) as a reference, and the results were compared to precise global positioning system (GPS) levelling networks in Scandinavia. An investigation of the Helmert method, focusing on the different types of indirect effects and their effects on the geoid, was also carried out. The three different methods used produce almost identical results at the 5-cm level, when compared to the GPS levelling networks. However, small systematic differences existed. Springer-Verlag Berlin Heidelberg, 2000 Key words: Terrain effects - Indirect effects - RTM - Helmert - Gravity - Geoid - GPS/levelling nationallicence Omang O. C. D. Department of Mapping Sciences, P.O. Box 5034 NLH, Agricultural University of Norway, 1432 Ås, Norway e-mail: ove.dahl@ikf.nlh.no, NO aut Forsberg R. Geodynamic Department, National Survey and Cadastre, Rentemestervej 8, 2400 Copenhagen NV, Denmark e-mail: rf@kms.dk, DK aut https://doi.org/10.1007/s001900000107 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s001900000107 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Omang O. C. D. Department of Mapping Sciences, P.O. Box 5034 NLH, Agricultural University of Norway, 1432 Ås, Norway e-mail: ove.dahl@ikf.nlh.no, NO aut NATIONALLICENCE 700 1- Forsberg R. Geodynamic Department, National Survey and Cadastre, Rentemestervej 8, 2400 Copenhagen NV, Denmark e-mail: rf@kms.dk, DK aut Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer