Position Vector transformation (geog2D domain)
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Position Vector transformation (geog2D domain) Open
Coordinate Operation Method Details [VALID]
Name: Position Vector transformation (geog2D domain)
Code: 9606
Operation is Reversible: Yes
Formula: 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 Position Vector transformation (geog2D domain) 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 Position Vector(geocentric domain) method, EPSG method code 1033;

(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.
Example: Input point:
Coordinate reference system: WGS 72 (geographic 2D)
Latitude = 55 deg 00 min 00 sec N
Longitude = 4 deg 00 min 00 sec E

This is taken to be geographic 3D with an assumed Ellipsoidal height hS = 0 m

This transforms to Cartesian geocentric coords:
Xs = 3 657 660.66 (m)
Ys = 255 768.55 (m)
Zs = 5 201 382.11 (m)

Transformation parameters WGS 72 to WGS 84:
tX (m) = 0.000
tY (m) = 0.000
tZ (m) = 4.5
rX (") = 0.000 = 0.0 radians
rY (") = 0.000 = 0.0 radians
rZ (") = 0.554 = 0.000002685868 radians
dS (ppm) = 0.219

from which M = 1.000000219

Application of the 7 parameter Position Vector transformation results in WGS 84 coordinates of:
Xt = 3 657 660.78 (m)
Yt = 255 778.43 (m)
Zt = 5 201 387.75 (m)

This converts into:
Latitude = 55 deg 00 min 00.090 sec N
Longitude = 4 deg 00 min 00.554 sec E
Ellipsoidal height = +3.22 m
on the WGS 84 geographic 3D coordinate reference system. For the 2D equivalent the height is ignored.
Method
Parameters:
Parameter Name Parameter Code Sign reversal Parameter Description
X-axis translation 8605 Yes The difference between the X values of a point in the target and source coordinate reference systems.
Y-axis translation 8606 Yes The difference between the Y values of a point in the target and source coordinate reference systems.
Z-axis translation 8607 Yes The difference between the Z values of a point in the target and source coordinate reference systems.
X-axis rotation 8608 Yes The angular difference between the Y and Z axes directions of target and source coordinate reference systems. This is a rotation about the X axis as viewed from the origin looking along that axis. The particular method defines which direction is positive, and what is being rotated (point or axis).
Y-axis rotation 8609 Yes The angular difference between the X and Z axes directions of target and source coordinate reference systems. This is a rotation about theY axis as viewed from the origin looking along that axis. The particular method defines which direction is positive, and what is being rotated (point or axis).
Z-axis rotation 8610 Yes The angular difference between the X and Y axes directions of target and source coordinate reference systems. This is a rotation about the Z axis as viewed from the origin looking along that axis. The particular method defines which direction is positive, and what is being rotated (point or axis).
Scale difference 8611 Yes Scale factor for source CRS axes minus one, where the scale factor is a multiplication factor to be applied to coordinates in the source CRS to obtain the correct scale in the target CRS. dS = (M – 1). If a distance of 100 km in the source CRS translates into a distance of 100.001 km in the target CRS, the scale difference is 1 ppm (the ratio being 1.000001). When the scale difference dS is expressed in parts per million (ppm), M = (1 + dS*10-6). When the scale difference dS is expressed in parts per billion (ppb), M = (1 + dS*10-9).