Corrected map of France: showing the coastline of France after scientifically mapping it in the late 17th century

“Map of France“
“Corrected on the order of the King, according to the observations of the Master of the Academy of Sciences”

The map above shows, the difference between using single latitude observations combined with ships’ logs versus triangulation.

Triangulation was spearheaded by the French dynasty of royal cartographers, the Cassini family, and is basically the same mathematical technique being used by surveyors today, just with lasers and satellites as aides now.