Metres above the Sea (Switzerland)

Metres above the Sea (German: Meter über Meer (m ü. M.)) is the vertical datum used in Switzerland.

The reference point for the Swiss national height network is the Pierres du Niton (French: Neptune's Stones), a pair of unusual rocks in the harbour of Lake Geneva.

As the height of the Pierres du Niton had been inaccurately measured in 1845 as being 376.86 meters, height information relating to this old horizon (for example in the Siegfried Map and the Dufour Map, both of them widely used) is 3.26 m higher than today's official values.

[4] As gravitational potential cannot be neglected for applications with high accuracy requirements, the Swiss national height network 1995 (LHN95) created a new orthometric height vertical reference point, fixed to the geoid.

[6] Establishment of a clearly understood common reference system is particularly important in cross-border projects involving Switzerland, because of the differing reference systems used in its neighboring countries.