Information about Helmert / Molodensky Parameter Sets

This function group provides functions for the calculation of highly exact transformation parameters for the Spatial Helmert and Molodensky Transformation, which make possible precise Coordinate Transformations from one Reference System into another. The determined transformation parameters can be entered directly into suitable transformation software, e.g. TRANSDAT Coordinate Transformations, or into the calculation software of GPS receivers to do exact Coordinate Transformations.

The seven respectively three exact transformation parameters are computed with the aid of up to 30.000 identical points. Those are points with known coordinates in two different Reference Systems. Identical measuring points of higher order can be inquired or referred by the official measurement surveys.

The coordinates of the identical points can be tested on outliers and residuals by different statistic functions. The quality of the computed parameters can be documented by a residual matrix and by the computation of the middle, maximum and root mean square (RMS) deviations.

Coordinates can be corrected using the identical points of the target reference system the calculated gaps. The correction is performed using the Residual Gaps Distribution by Natural Neighbour Interpolation.

The seven parameters of the Spatial Helmert Transformation are calculated in the three standards "Coordinate Frame Rotation", "Position Vector Transformation" and "European Standard ISO 19111". The three parameters for Molodenky parameter sets are calculated using the "Standard Molodensky Transformation".