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Regional Models

Thailand (THAI12G/THAI12H)

  Authors: P. Dumrongchai, C. Wichienchareon, C. Promtong     Created: 2012    Resp: P. Dumrongchai  
      Status: PRIVATE   
THAI12G and THAI12H are a gravimetric and a hybrid geoid for Thailand, respectively. The THAI12G model is referred to the geocentric WGS84 ellipsoid and it is computed through the one-dimensional spherical Fast Fourier Transform (FFT) in the framework of a remove-restore procedure. In particular, the non-tidal EGM2008 global geopotential model from degree 2 to 2190 and 3,949 terrestrial gravity measurements were used to contribute long- and medium-scale information of the geoid structure. The topography-implied gravity anomalies were generated by using the high-resolution residual terrain model (RTM) data from the three-arcsecond SRTM digital elevation model. The THAI12H hybrid geoid was computed by adapting the THAI12G gravimetric geoid to 200 GPS/levelling points through least-squares collocation (LSC). The resulting surface was assessed by using 53 GPS/levelling check points, yielding an overall rms of 16.1 cm. The THAI12H model directly relates GPS heights in WGS84 datum to orthometric heights in the national vertical datum (Kolak-1915).

P. Dumrongchai, C. Wichienchareon, C. Promtong (2012). Local Geoid Modeling for Thailand. International Journal of Geoinformatics, 8(4), pp. 15-26.

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