Before revision: Topographic view of Earth relative to Earth's center (instead of to mean sea level, as in common topographic maps) By the late 1600s, serious effort was devoted to modeling the Earth as an ellipsoid, beginning with Jean Picard's measurement of a degree of arc along the Paris meridian.
After revision: French astronomerTopographic view of Earth relative to Earth's center (instead of to mean sea level, as in common topographic maps) By the late 1600s, serious effort was devoted to modeling the Earth as an ellipsoid, beginning with Jean Picard's measurement of a degree of arc along the Paris meridian.