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Numerically these two sets of coordinates will be different but they will continue to represent the same physical point in space, as can be seen in figures 10 and 11. The corollary is that coordinates referenced to one datum that are mapped in a different datum will appear in the wrong place! The reader should note that in some of the larger regional datums, there are a variety of 3 parameter datum transformation sets depending on where in the region the operator is working (figure 12).
Figure 11: Shows three latitude and longitude locations referenced to different geodetic datums that all represent the same point. The differences in the right-hand two columns shows the error in mapped location if the datums are confused.
Figure 12: Shows various datum transformation parameters in China as they relate to WGS 84. Datums in China are WGS 84, WGS 72 BE, Beijing 1954 and Xian 1980. Note the difference in the parameters for the Beijing datum in the Ordos and Tarim basin, both three parameter transformations and the difference between the South China Sea and the Yellow Sea seven parameter transformations.
These are captured in the EPSG parameter database. Note also there are more sophisticated methods of calculating the datum transformation which may appear in various applications. These include parameters that not only translate but also allow for rotation and scaling differences between the two datums. The EPSG parameter database also contains many of these. Care should be taken when applying such parameters, and it is best to obtain the services of a specialist when using them or coding them into software. For most applications in the E&P domain, a three parameter shift will provide the necessary accuracy. In some countries more elaborate parameters are required by law.
LINK
EPSG parameter database
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