Venerated maps with centuries-old misinformation were found to be increasingly inconsistent with recent observations by mariners of the Age of Exploration. His solution to the problem of distortion of physical features on the sphere of the earth when projected onto a flat map was the cylindrical, or Mercator, projection still in use today.
Old maps show the coast of North America and Iceland, country of issue.
Franklin published maps of the newly founded United States and he also mapped the currents of the gulf stream during his frequent crossings to Europe. In 1701 Halley had already published a map of magnetic declinations, and the subject was studied by Humboldt, de Borda, and Gay-Lussac, among others. Hansteen collected available data and also mounted an expedition to Siberia, where he took many measurements for an atlas of magnetic strength and declination. He was a geologist, naturalist and collector of specimens who wrote an encyclopedic work in geology and geography, Kosmos. Wegener noticed how the the shapes of Brazil and Africa fit together.