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Geographic offsets

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New in version 6.0.0.

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The Geographic offsets transformation adds an offset to the geographic longitude, +latitude coordinates, and an offset to the ellipsoidal height.

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Alias

geogoffset

Domain

3D

Input type

Geodetic coordinates (horizontal), meters (vertical)

output type

Geodetic coordinates (horizontal), meters (vertical)

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This method is normally only used when low accuracy is tolerated. It is documented +as coordinate operation method code 9619 (for geographic 2D) and 9660 (for +geographic 3D) in the EPSG dataset ([IOGP2018])

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It can also be used to implement the method Geographic2D with Height Offsets +(code 9618) by noting that the input vertical component is a gravity-related +height and the output vertical component is the ellipsoid height (dh being +the geoid undulation).

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It can also be used to implement the method Vertical offset (code 9616)

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The reverse transformation simply consists in subtracting the offsets.

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This method is a conveniency wrapper for the more general Affine transformation.

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Examples

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Geographic offset from the old Greek geographic 2D CRS to the newer GGRS87 CRS:

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proj=geogoffset dlon=0.28 dlat=-5.86
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Conversion from Tokyo + JSLD69 height to WGS 84:

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proj=geogoffset dlon=-13.97 dlat=7.94 dh=26.9
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Conversion from Baltic 1977 height to Black Sea height:

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proj=geogoffset dh=0.4
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Parameters

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Optional

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++dlon=<value>
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Offset in longitude, expressed in arc-second, to add.

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++dlat=<value>
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Offset in latitude, expressed in arc-second, to add.

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++dh=<value>
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Offset in height, expressed in meter, to add.

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