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Regional Models

Hawaiian Islands (GEOID99)


  Authors: D.A. Smith, D.R. Roman     Created: 1999    Resp: D.R. Roman  
      Status: PUBLIC    

Description:
GEOID99 is a gravimetric geoid model for Hawaiian Islands computed by the National Geodetic Survey (NGS). It is referred to the GRS80 normal ellipsoid in the ITRF96 frame (epoch 1997.0). It has a 1'x1' spatial resolution in latitude and longitude. Unlike the grid for the conterminous United States, this GEOID99 model does not incorporate GPS/levelling data. The gravimetric geoid determination for Hawaiian Islands is based on the same techniques as G99SSS for the conterminous United States, namely on the use of the one-dimensional spherical Fast Fourier Transform (FFT) to evaluate Stokes' integral. It is performed in the framework of a remove-restore procedure, where long wavelengths come from the EGM96 geopotential model, while the terrain correction is computed by using a digital elevation model with a spatial resolution of 3''x3''. Due to poorer data coverage, error estimates for GEOID99 in this region are larger than the ones of G99SSS in the conterminous United States.

References:
D.A. Smith, D.R. Roman (2001). GEOID99 and G99SSS: 1-arc-minute geoid models for the United States. Journal of Geodesy, 75(9), pp. 469-490.

Hawaii