EPSG

EPSG guidance note #7-2, http://www.epsg.org

2019-02-21

Note the analogy with the Position Vector tfm (code 9606) but beware of the differences! The Position Vector convention is used by IAG and recommended by ISO 19111. See methods 1032 and 1038 for similar tfms operating between other CRS types.

Note: These formulas have been transcribed from EPSG Guidance Note #7-2. Users are encouraged to use that document rather than the text which follows as reference because limitations in the transcription will be avoided. Transformation of coordinates from one geographic coordinate reference system into another is often carried out as a concatenation of the following operations: (geographical to geocentric) + (geocentric to geocentric) + (geocentric to geographic) The Coordinate Frame rotation (geog2D domain) transformation has 5 steps: (i) geographic 2D coordinates are converted to 3D using EPSG coordinate operation method code 9659; (ii) geographic 3D coordinates are converted to geocentric coordinates using EPSG coordinate operation method code 9602; (iii) the middle step of the concatenated transformation, from geocentric coordinates to geocentric coordinates, uses the Coordinate Frame rotation (geocentric domain) method, EPSG method code 1032; (iv) the geocentric coordinates are converted to geographic 3D using EPSG coordinate operation method code 9602; (v) finally the geographic 3D coordinates are converted to geographic 2D using EPSG coordinate operation method code 9659.

The same example as for the Position Vector transformation (coordinate operation method 9606) can be calculated, however the following transformation parameters have to be applied to achieve the same input and output in terms of coordinate values: Transformation parameters Coordinate Frame rotation convention: tX (m) = 0.000 tY (m) = 0.000 tZ (m) = 4.5 rX (") = 0.000 rY (") = 0.000 rZ (") = -0.554 = -0.000002685868 radians dS (ppm) = 0.219 from which M = 1.000000219 Please note that only the rotation has changed sign as compared to the Position Vector transformation.