Seven-parameter conformal coordinate transformations, also known as Helmert transformations, can be constructed in more than one way. Two possible orderings of the rotations are in common use, giving rise to Helmert versions 1 and 2. It is demonstrated how the rotation parameters of either version can be converted into the rotation parameters of the other. This is useful when software is designed for the other version. It also enables computation of the same-formula inverse transformation by changing the sign of the equivalent ‘other version’ parameters. These results were primarily intended for conformal transformations between geodetic datums. They can, however, be extended to coordinate transformations in disciplines such as photogrammetry where rotations sometimes exceed 90 degrees.

可以以多种方式构造七参数共形坐标变换，也称为Helmert变换。旋转的两种可能的顺序是常用的，产生了Helmert版本1和2。它演示了如何将任一版本的旋转参数转换为另一版本的旋转参数。当软件是为其他版本设计的时，这很有用。它还可以通过更改等效“其他版本”参数的符号来计算相同公式的逆变换。这些结果主要用于大地基准之间的共形转换。但是，它们可以扩展以协调摄影测量等学科中的转换，其中旋转有时超过90度。