General levelling of France
Encyclopedia
The General Levelling of France (nivellement général de la France
or NGF)
forms a network of benchmarks in mainland France and Corsica
, now overseen by the Institut Géographique National. It is now the official levelling
network in mainland France. It is made up of two networks:
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...
or NGF)
forms a network of benchmarks in mainland France and Corsica
Corsica
Corsica is an island in the Mediterranean Sea. It is located west of Italy, southeast of the French mainland, and north of the island of Sardinia....
, now overseen by the Institut Géographique National. It is now the official levelling
Levelling
Levelling or leveling is a branch of surveying, the object of which is1) To find the elevation of a given point with respect to the given or assumed Datum.2) to establish a point at a given elevation with respect to the given or assumed Datum....
network in mainland France. It is made up of two networks:
- NGF - IGN69 for mainland France, with the 'zero level' determined by the tide gaugeTide gaugeA tide gauge is a device for measuring sea level and detecting tsunamis.Sensors continuously record the height of the water level with respect to a height reference surface close to the geoid...
at MarseilleMarseilleMarseille , known in antiquity as Massalia , is the second largest city in France, after Paris, with a population of 852,395 within its administrative limits on a land area of . The urban area of Marseille extends beyond the city limits with a population of over 1,420,000 on an area of... - NGF - IGN78 for CorsicaCorsicaCorsica is an island in the Mediterranean Sea. It is located west of Italy, southeast of the French mainland, and north of the island of Sardinia....
, with the 'zero level' determined by the tide gauge at AjaccioAjaccioAjaccio , is a commune on the island of Corsica in France. It is the capital and largest city of the region of Corsica and the prefecture of the department of Corse-du-Sud....