My favourite early navigation story:
Someone studying local geographic knowledge in the Canadian Arctic asked an Inuit to draw a map of a common hunting/migration route made by kayak (often solo). Portions of it were out of sight of land for more than a day. Initially the researcher was somewhat amused at how crude the map was compared to modern topographic charts. All lumpy and distorted, some smallish landmark features drawn large and other very large bays drawn as just a small gap.
Eventually however the realization dawned that the underlying metric, the coordinate system if you will, …
The Mercator projection (1536) must be great for nautical navigation. It allows one to find a bearing and keeping this constant one should reach the target (if not in the shortest line). But how did people navigate before this? As an example Magellan circumnavigated the globe ca. 1520.
