Paris meridian
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The Paris meridian is a meridian line running through the Paris Observatory in Paris, France – now longitude 2°20′14.02500″ East. It was a long-standing rival to the Greenwich meridian as the prime me
Meridian Room (or Cassini Room) at the Paris Observatory, 61 avenue de l'Observatoire (14th arrondissement). The Paris meridian is traced on the floor.
The triangulation mesh of the Anglo-French survey 1784–1790
The West Europe-Africa Meridian-arc extending south from the Shetland Islands, through Great Britain, France and Spain to El Aghuat in Algeria, whose parameters were calculated from surveys carried out in the mid to late 19th century. It yielded a value for the equatorial radius of the Earth a = 6 377 935 metres, the ellipticity being assumed as 1/299.15. The radius of curvature of this arc is not uniform, being, in the mean, about 600 metres greater in the northern than in the southern part. The
One of the 135 Arago medallions. This one is located near the Louvre Pyramid.
History of geodesy
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The history of geodesy began during antiquity and ultimately blossomed during the Age of Enlightenment.
Round Earth umbra during the August 2008 lunar eclipse
Spherical Earth with the four seasons. Illustration in 12th-century book Liber Divinorum Operum by Hildegard of Bingen
John Gower prepares to shoot the world, a sphere with compartments representing earth, air, and water (Vox Clamantis, around 1400)
The beginning of the U. S. coastal survey.