Geographic3D to GravityRelatedHeight (BEV AT)

Formula

This transformation involves the application of a geoid-ellipsoid separation value interpolated from a geoid model. The model provides separation values at the nodes on a regular grid of latitude and longitude intersection points. The geodetic latitude and longitude used to interpolate within the grid are not affected by this transformation.

The grid is referenced to a specific geographic CRS (the horizontal component of the source CRS) and interpolation must be made in the latitude and longitude of this system.

Calculation of the separation is achieved through interpolation of the grid, using the latitude and longitude of the point. This step provides the geoid-ellipsoid separation (N) above the ellipsoid of the source Geographic 3D CRS.

Then:
           H = h - N

where h = the height above the ellipsoid in the source geographic 3D CRS
and   H = the gravity-related height in the target vertical CRS.

Example

For a point at 48.829794943°N, 15.28122821°E, ellipsoidal height of 549.97 metres ETRS89 3D):

Using bi-linear interpolation of the Hohengrid Plus grid for 48.829794943°N, 15.28122821°E, the resulting offset = 46.20m

Then Austrian GHA height = 549.97m - (46.20m) = 503.77m.

EPSG:1081

Geographic3D to GravityRelatedHeight (BEV AT)

Attributes

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Formula

Example