"obeys to" sounds carelessly translated from French.
"His Mercator projection map, first completed in 1569, straightened the earth’s surface and opened a new era in cartography and maritime navigation." Well, it gave a flattened representation of the earth's surface, but what paper map doesn't? I also question the "new era" as far as maritime navigation. Yes, the Mercator projection shows compass courses as straight lines, but a lot of people, with or without compasses, had sailed a lot of places and back already. Magellan's expedition had been around the world by then.
"His Mercator projection map, first completed in 1569, straightened the earth’s surface and opened a new era in cartography and maritime navigation." Well, it gave a flattened representation of the earth's surface, but what paper map doesn't? I also question the "new era" as far as maritime navigation. Yes, the Mercator projection shows compass courses as straight lines, but a lot of people, with or without compasses, had sailed a lot of places and back already. Magellan's expedition had been around the world by then.