Module geodesy.transform.helmert
Static 7-parameter EPSG Helmert transformations in geocentric coordinates.
The rotation convention is encoded in the public type so Position Vector and Coordinate Frame parameters cannot be silently mixed. Both conventions share one parameter model while remaining distinct D types, and explicit conversion between conventions negates only the rotation parameters.
Standards
EPSG method 1033 -- Position Vector transformation (geocentric domain). EPSG method 1032 -- Coordinate Frame rotation (geocentric domain).
Units
Translations use the geocentric coordinate linear unit. Canonical rotations are strong angles in radians; the EPSG interchange factory accepts arc-seconds. Scale difference is dimensionless, with a parts-per-million interchange form.
Numerics
Implements the EPSG small-angle linearized rotation equations rather than silently substituting an exact finite-angle 3D rotation.
Performance
Prepared parameters transform coordinates with allocation-free constant-space arithmetic.
Validation
Convention mapping and numerical results are covered by EPSG semantics, internal tests, and PROJ differential comparisons for both 1032 and 1033.
See Also
PositionVectorHelmert, CoordinateFrameHelmert,
GeocentricTranslation, GeocentricCoordinate
Date
September 26, 2026
Functions
| Name | Description |
|---|---|
applyCoordinateFrameHelmert(source, transform)
|
Apply EPSG method 1032 Coordinate Frame in the source-to-target direction. |
applyPositionVectorHelmert(source, transform)
|
Apply EPSG method 1033 Position Vector in the source-to-target direction. |
toCoordinateFrame(source)
|
Convert an EPSG 1033 Position Vector parameter set into the equivalent EPSG 1032 Coordinate Frame parameter set. |
toPositionVector(source)
|
Convert an EPSG 1032 Coordinate Frame parameter set into the equivalent EPSG 1033 Position Vector parameter set. |
tryApplyCoordinateFrameHelmert(source, transform, result)
|
Apply EPSG method 1032 Coordinate Frame in the source-to-target direction. |
tryApplyPositionVectorHelmert(source, transform, result)
|
Apply EPSG method 1033 Position Vector in the source-to-target direction. |
Structs
| Name | Description |
|---|---|
Helmert7
|
Seven source-to-target Helmert parameters with rotation convention encoded in the type. |
Enums
| Name | Description |
|---|---|
HelmertConvention
|
EPSG Helmert rotation convention. |
Aliases
| Name | Type | Description |
|---|---|---|
CoordinateFrameHelmert
|
Helmert7!(T,HelmertConvention.coordinateFrame)
|
EPSG 1032 Coordinate Frame parameter type. |
PositionVectorHelmert
|
Helmert7!(T,HelmertConvention.positionVector)
|
EPSG 1033 parameter type. |