Marseille level
The Marseille gauge indicates the reference level for France .
history
The different heights of the sea level in the Mediterranean were measured with a mareograph near Marseille . The mean of the values was then set as the reference level. The tides are weak in the Mediterranean.
In the course of time, different definitions of the Marseille level have been used, but they hardly differ:
- Bourdaloue zero from 1860
- Lallemand zero from 1897 from the values from 1884 to 1896
- IGN69 zero from 1969.
The definition of the Marseille level also influenced the definition of altitude in Switzerland. Until 1902, the Swiss high altitude reference point Repère Pierre du Niton was defined as 376.86 m above the Marseille gauge. In order to compensate for deviations, the Swiss figure was set at 373.6 m above the Marseille gauge in 1902.
Mareograf in Marseille
Since the establishment of the zero point, the height indication of the Marseille level has in principle been independent of water level fluctuations . Only the word level in the name reminds of the dependence on a water level .
See also
Web links
- Description of the mareographer (French, PDF, 2 MB)
Individual evidence
- ↑ http://education.ign.fr/sites/all/files/nivellement_histoire.pdf
- ↑ http://education.ign.fr/sites/all/files/nivellement_reseaux.pdf
- ↑ https://www.swisstopo.admin.ch/de/wissen-ffekten/geodaesie-vermessung/fragen.html
Coordinates: 43 ° 16 ′ 43 ″ N , 5 ° 21 ′ 13 ″ E