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Transformations (3D / position)

For handling spatial data, it is important to have an easy and accurate transition between the various reference systems and frames. swisstopo offers suitable transformation methods for all applications, either through online services over the Internet or commercially available geodetic software.

Coordinate transformation ETRFyyyy <-> CHTRFyyyy

The reference systems ETRS89 and CHTRS95 are identical for the epoch t0 = 1993.0. The two reference frames may therefore be regarded as identical for applications requiring reduced accuracy (ETRFyyyy ~ CHTRFyyyy). 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.

Coordinate transformation CHTRFyyyy <-> LV95

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 CHTRFyyyy and LV95. Only the different ellipsoid dimensions and the map projections must still be taken into consideration

 

Coordinate transformation
Coordinate transformation CHTRS95 -> CH1903+ (X, Y, Z) LV95 = (X, Y, Z) CHTRFyy + ( -674.374m, -15.056m, -405.346m)

Coordinates transformation LV95 <-> LV03

An exact transformation is not possible because of the large distortions (up to 1.6 metres). The distortion may be approximated with an affine transformation using finite elements. An approximation to LV03 with a degree of accuracy within a few centimetres in the Central Plateau and below 1 decimetre in the Alps can be calculated with the REFRAME programme and using the CHENYX06 dataset from the triangular transformation network.

A NTV2 grid data set for transforming to ETRS or to LV95 is distributed in our Shop under open data licence Creative Commons CC0.

Transition of reference frames shown graphically
The image shows the coordinates transformation between the old and the new Swiss reference frame (up to 1.6 metres). The shift vectors are colour coded.

Triangular transformation network
Triangular transformation network CHENyx06


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+41 58 469 01 11

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Geodesy and Federal Directorate of Cadastral Surveying
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Federal Office of Topography swisstopo

Seftigenstrasse 264
P.O. Box
3084 Wabern

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