Cassini map

The Cassini Map or Academy's Map is the first topographic and geometric map made of the Kingdom of France as a whole. It was compiled by the Cassini family, mainly César-François Cassini (Cassini III) and his son Jean-Dominique Cassini (Cassini IV) in the 1700s.  The map was, for the time, a real innovation and a decisive technical advance. It is the first map to be based on a geodesic triangulation. Four generations of the Cassini carried out the work, taking more than 6 decades to complete.  Poor Cassini IV was imprisoned by the National Assembly for being royalist, but they still availed themselves of his map.