Matches in SemOpenAlex for { <https://semopenalex.org/work/W2525202032> ?p ?o ?g. }
- W2525202032 abstract "One goal of modern geodesy is the global unification of vertical datums so that height data from them can be properly integrated. This thesis studies the unification of the 13 disparate levellingand tide-gauge-based vertical datums in New Zealand (NZ). It proposes a new NZ-wide single vertical datum based on a gravimetric quasigeoid model to unify the existing local vertical datums. This will also include methods to transform height data in terms of the existing datums to the new datum and vice versa. After defining and comparing the main types of height system and vertical datum used around to world, the system of heights used in NZ was shown to be normalorthometric. Consequently, datum unification was achieved using a quasigeoid model, as opposed to a geoid model. The quasigeoid was computed by combining the GRACE-based GGM02 and EGM96 global geopotential models with land gravity data (40,737 observations) and a 56-m resolution digital elevation model (DEM). Marine gravity data came from a least-squares collocation combination of 1,300,266 crossover-adjusted ship track observations and gravity anomalies derived from multi-mission satellite altimetry. To ensure that the best quasigeoid was computed for the NZ datasets, a number of computation processes were compared and contrasted. The Hammer chart, fast Fourier transform (FFT) and prism integration methods of computing terrain corrections (TCs) were compared. This showed that the prism integration TC is the most realistic in NZ. The mean Helmert gravity anomalies, required for numerical integration of Stokes’s formula, were computed via refined Bouguer anomalies with the prism TCs, and reconstruction with heights from the DEM used to ‘reconstruct’ more representative mean anomalies. In addition, five deterministic modifications to Stokes’s formula were compared. There was little difference between three of them, so the Featherstone et al. (1998) modification ( 0 ψ = 1.5°, M = 40) was chosen because it is theoretically better than its predecessors. The global geopotential, gravimetric geoid, sea surface topography and geodetic boundary-value problem approaches to vertical datum unification were then contrasted. As none was likely to be effective in NZ, a new iterative quasigeoid" @default.
- W2525202032 created "2016-10-07" @default.
- W2525202032 creator A5003083061 @default.
- W2525202032 date "2007-01-01" @default.
- W2525202032 modified "2023-09-28" @default.
- W2525202032 title "Quasigeoid modelling in New Zealand to unify multiple local vertical datums" @default.
- W2525202032 cites W103863228 @default.
- W2525202032 cites W137728122 @default.
- W2525202032 cites W1494283195 @default.
- W2525202032 cites W1504085430 @default.
- W2525202032 cites W1511720900 @default.
- W2525202032 cites W1529627347 @default.
- W2525202032 cites W1542795157 @default.
- W2525202032 cites W1547074707 @default.
- W2525202032 cites W1574556484 @default.
- W2525202032 cites W1584735066 @default.
- W2525202032 cites W1588827410 @default.
- W2525202032 cites W1604283571 @default.
- W2525202032 cites W1618474555 @default.
- W2525202032 cites W163362759 @default.
- W2525202032 cites W1644071718 @default.
- W2525202032 cites W1646923252 @default.
- W2525202032 cites W1665339821 @default.
- W2525202032 cites W1678349883 @default.
- W2525202032 cites W1681032811 @default.
- W2525202032 cites W181400984 @default.
- W2525202032 cites W1883685208 @default.
- W2525202032 cites W1920339998 @default.
- W2525202032 cites W1951817746 @default.
- W2525202032 cites W1963897307 @default.
- W2525202032 cites W1964087794 @default.
- W2525202032 cites W1967453661 @default.
- W2525202032 cites W1967705083 @default.
- W2525202032 cites W1968456401 @default.
- W2525202032 cites W1969087874 @default.
- W2525202032 cites W1971327941 @default.
- W2525202032 cites W1971521735 @default.
- W2525202032 cites W1972255152 @default.
- W2525202032 cites W1973006875 @default.
- W2525202032 cites W1973478065 @default.
- W2525202032 cites W1975095204 @default.
- W2525202032 cites W1977431270 @default.
- W2525202032 cites W1980254105 @default.
- W2525202032 cites W1983283503 @default.
- W2525202032 cites W1983563332 @default.
- W2525202032 cites W1984195633 @default.
- W2525202032 cites W1985550342 @default.
- W2525202032 cites W1986777674 @default.
- W2525202032 cites W1987616603 @default.
- W2525202032 cites W1989300742 @default.
- W2525202032 cites W1989414233 @default.
- W2525202032 cites W1990962698 @default.
- W2525202032 cites W1991040489 @default.
- W2525202032 cites W1991513494 @default.
- W2525202032 cites W1992234940 @default.
- W2525202032 cites W1995809323 @default.
- W2525202032 cites W1996014631 @default.
- W2525202032 cites W1997659016 @default.
- W2525202032 cites W1998406198 @default.
- W2525202032 cites W2001092866 @default.
- W2525202032 cites W2004117811 @default.
- W2525202032 cites W2006023974 @default.
- W2525202032 cites W2007106142 @default.
- W2525202032 cites W2008325629 @default.
- W2525202032 cites W2009158827 @default.
- W2525202032 cites W2010369688 @default.
- W2525202032 cites W2011945663 @default.
- W2525202032 cites W2013923435 @default.
- W2525202032 cites W2014650445 @default.
- W2525202032 cites W2014861575 @default.
- W2525202032 cites W2016532963 @default.
- W2525202032 cites W2017601795 @default.
- W2525202032 cites W2018131080 @default.
- W2525202032 cites W2018314772 @default.
- W2525202032 cites W2018506778 @default.
- W2525202032 cites W2020629919 @default.
- W2525202032 cites W2020977965 @default.
- W2525202032 cites W2021388350 @default.
- W2525202032 cites W2021973023 @default.
- W2525202032 cites W2023073459 @default.
- W2525202032 cites W2025231371 @default.
- W2525202032 cites W2025966436 @default.
- W2525202032 cites W2027733834 @default.
- W2525202032 cites W2028787741 @default.
- W2525202032 cites W2028972906 @default.
- W2525202032 cites W2030790524 @default.
- W2525202032 cites W2032984378 @default.
- W2525202032 cites W2033746533 @default.
- W2525202032 cites W2034083228 @default.
- W2525202032 cites W2039274971 @default.
- W2525202032 cites W2040513229 @default.
- W2525202032 cites W2041442792 @default.
- W2525202032 cites W2042422285 @default.
- W2525202032 cites W2043124831 @default.
- W2525202032 cites W2043329693 @default.
- W2525202032 cites W2045721305 @default.
- W2525202032 cites W2046942769 @default.
- W2525202032 cites W2047416862 @default.
- W2525202032 cites W2052941111 @default.
- W2525202032 cites W2055628055 @default.