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The Cassini Map or Academy's Map is the first topographic and geometric map made of the
File:Besancon-Planoise Cassini map.jpg
File:Carte de Cassini Saint Souplet.jpg
File:Cassini map of France 68.png
The Cassini Map or Academy's Map is the first topographic and geometric map made of the Kingdom of France
The Kingdom of France ( fro, Reaume de France; frm, Royaulme de France; french: link=yes, Royaume de France) is the historiographical name or umbrella term given to various political entities of France in the medieval and early modern period ...
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.
It was on a scale of one line
Line most often refers to:
* Line (geometry), object with zero thickness and curvature that stretches to infinity
* Telephone line, a single-user circuit on a telephone communication system
Line, lines, The Line, or LINE may also refer to:
Art ...
to 100 toise
A toise (; symbol: T) is a unit of measure for length, area and volume originating in pre-revolutionary France. In North America, it was used in colonial French establishments in early New France, French Louisiana (''Louisiane''), Acadia (''Acadi ...
s, i.e. 1/86,400.
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
In geometry, a geodesic () is a curve representing in some sense the shortest path ( arc) between two points in a surface, or more generally in a Riemannian manifold. The term also has meaning in any differentiable manifold with a connection. ...
triangulation. Four generations of the Cassini carried out the work, taking more than 6 decades to complete. The map does not precisely locate dwellings or the boundaries of swamps and forests, but the level of precision of the road network represented is such that by superimposing satellite photos onto map sheets of France, spectacular results are obtained.
The work of the Cassinis even left its mark on the land where today you can still find toponyms such as "''Signal of Cassini."'' Such landmarks correspond to the corners of the triangles that formed the backbone of Cassini's map.
Nowadays, researchers frequently consult the Cassini map sheets, ie its paper form in the reading room of the maps and plans department of the Bibliothèque nationale de France
The Bibliothèque nationale de France (, 'National Library of France'; BnF) is the national library of France, located in Paris on two main sites known respectively as ''Richelieu'' and ''François-Mitterrand''. It is the national reposito ...
, or its digital form online. It is of particular interest to archaeologists, architects, historians, geographers, genealogists, treasure hunters and ecologists who need to retrospect ecology or understand the history of landscape.
The Map's Beginnings
The genesis of the Cassini Map came during the reign of Louis XIV, with the creation of theAcademy of Sciences
An academy of sciences is a type of learned society or academy (as special scientific institution) dedicated to sciences that may or may not be state funded. Some state funded academies are tuned into national or royal (in case of the Unit ...
alongside the ambitions of Jean-Baptiste Colbert
Jean-Baptiste Colbert (; 29 August 1619 – 6 September 1683) was a French statesman who served as First Minister of State from 1661 until his death in 1683 under the rule of King Louis XIV. His lasting impact on the organization of the countr ...
for France's navy, the defence of her coasts and fixing the imprecision of the country's maps. At the time distances between settlements, to be portrayed on maps, were often estimated by the time of the journey between them or by measuring the length of the road. Sometimes, triangulation was used though often relying on the magnetic pin of a compass without concern for one's latitude. This would result in confounded errors when compiling these maps into one.
Cassini, alongside other scientists like Picard and Roëmer and Richer, investigated movement of the planets relative to Earth. Cassini noted such methods were bedridden with instrumental errors and were susceptible to parallax. Picard and La Hire write in 1672 that King Louis XIV instructed the Academy of Sciences to, "create a map of all of France with the greatest precision possible." , Cassini writes that in September 1672, M. Vivier had, ''"come by order of the King"'' and was, ''"employed by order of the King to work on the Map of the Kingdom under the direction of the Academy of Sciences."''
Gallery
See also
*French cartography
The history of French cartography can be traced to developments in the Middle Ages. This period was marked by improvements in measuring instruments and also by an upgrade of work in registers of all types. What is thought to be the oldest land map ...
References
External
Online portal found here: https://www.geoportail.gouv.fr/donnees/carte-de-cassini {{cartography topics