Bursa/Wolf Transformation

This transformation is actually an approximation of the Seven Parameter Transformation that has been traditionally used for geodetic transformation. This approximation has been used for many years, and is the transformation most often documented in less rigorous geodetic documentation. The approximation is very good as long as the three rotation angles are rather small, on the order of two or three seconds of arc. When rotation angles exceed these values, the results begin to strain normally expected levels of accuracy.

The approximation is arrived at by making three assumptions:

1    the sine of a small angle is equal to the angle (in radians) itself;

2    the multiplication of two sine terms is zero; and

3    the cosine of a small angle is one.

This approximation is valid only for small angles.

In all other aspects, this transformation is the same as the Seven Parameter transformation. In processing new data projects, use the Seven Parameter transformation in lieu of the Bursa/Wolf. The Bursa/Wolf approximation is provided for purpose of providing the means to reproduce numbers/calculations that were originally accomplished using the approximation.