Transformations (3D / position)

The reference systems ETRS89 and CHTRS95 are identical for the epoch t 0 = 1993.0. The two reference frames may therefore be regarded as identical for applications requiring reduced accuracy (ETRFyy ~ CHTRFyy). For applications requiring higher accuracy, a transformation in time is necessary. For this purpose, the kinematik model CHKM95 is applied, which takes into account the temporal changes of the coordinates and heights due to the tectonic movements in the Alpine region.

The three-dimensional Cartesian reference systems CHTRS95 and CH1903+ can be transformed exactly from one to the other with a simple translation (3 shifts). This method may also be applied without reservations to coordinates from the reference frames CHTRFyy and LV95. Only the different ellipsoid dimensions and the map projections must still be taken into consideration.

An exact transformation is not possible because of the large distortions (up to 1.6 m). The distortion may be approximated with an affine transformation using finite elements. An approximation to LV03 with an accuracy of a few cm in the Central Plateau and below 1 dm in the Alps can be calculated with the program FINELTRA using the corresponding parameters from the cadastral surveying authorities.