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Regional Models

France (QGF96)

  Author: H. Duquenne     Created: 1996    Resp: F. L'Ecu  
      Status: PUBLIC    
QGF96 is a French gravimetric quasi-geoid model, covering the area 42° < lat < 51.5°, -5.5° < lon < 8.5° with a grid spacing of 1.5' in latitude and 2' in longitude. The reference ellipsoid is GRS80. The model is computed by using the remove restore tecnhique with Stokes integration. It is based on about 270,000 gravity data, the OSU91A global geopotential model and a digital terrain model covering west Europe. The model has been checked by a comparison with 979 GPS/levelling points of the RGF93 network, showing residuals with a standard deviation of 12.8 cm after detrending.
The original quasi-geoid model is given in a grid format, each file containing:
- a header (unit degree):
- southern latitude, northern latitude
- western longitude, eastern longitude
- latitude increment, longitude increment
- the gridded data (unit meters):
- from north to south and for each latitude from west to east.
Additional information is available at the following IGN webpage:

H. Duquenne (1997). Le modele de quasi-geoide francais QGF96 et la surface de reference d'altitude RAF96. Ecole Superieure des Geometres et Topographes (ESGT), F91055-Evry, & Institut Geographique National (IGN), F94160-SaintMande, France.
H. Duquenne (1997). Comparison between the EGM96 model and the French quasi-geoid model. IGeS Bulletin, 6, pp. 131-134.