The old, still official reference system for cadastral surveying which was defined and introduced in 1903. The system comprises the definition of a reference ellipsoid (Bessel 1841) fixed in position and orientation to the old fundamental point (old observatory in Bern), the transformation in CHTRS95 and the Swiss oblique conformal cylinder projection («Swiss Grid»). CH1903 also defines the old official height system for which the «Repère Pierre du Niton» in the port of Geneva serves as the point of origin with a height of 373.6 m.
Swiss reference systems
In addition to the already existing reference system CH1903 which is still the standard for official cadastral surveying, GIS applications and cartography in Switzerland, a new Swiss global system (CHTRS95) and a revised Swiss local system (CH1903+) were defined in the scope of the new national survey LV95.
CH1903: Reference system of the old national survey 1903
- Old observatory in Bern
CH1903+: Reference system of the new national survey 1995
The new local reference system for the Swiss national survey LV95 which shall be introduced as the future basis for official cadastral surveying. CH1903+ uses the same ellipsoid (Bessel 1841) as CH1903. The spatial coordinate axes X, Y, Z are derived directly from CHTRS95 by translation (3 shifts). The map projection «Swiss Grid») is identical to CH1903. The new fundamental point Z0 at Geostation Zimmerwald serves as the point of origin for the height. Its orthometric height was defined as H0 = 897.9063 m, so that for the «Repère Pierre du Niton» in Geneva the value of 373.6 m is obtained.
- Geostation Zimmerwald
CHTRS95: Swiss Terrestrial Reference System 1995
The new global reference system for the Swiss national survey LV95 which is identical to ETRS89 with the point at the time t0 = 1993.0. The system includes the definition of the reference ellipsoid (GRS80) fixed in position and orientation to Z0 and uses the global map projection Universal Transverse Mercator (UTM). CHTRS95 also defines a new, theoretically rigorous orthometric height system with respect to the gravity field whose point of origin Z0 (Geostation Zimmerwald) has the orthometric height H0 = 897.8027 m (derived from the UELN95/98).
Further information
- Reference frames
- Geostation Zimmerwald
- Height reference
- Networks
- Transformation (3D / Position)
- Transformations in height
Documentation
- Reference system CH
19.11.2008 | 469 Kb | PDF
- Transformation CH1903 <-> WGS84
19.11.2008 | 113 Kb | PDF
Publications
- Swiss reference frame LV95
3350 Kb | PDF