I recently took a visit to the Vatican Museums, and I found the Gallery of Maps to be fascinating. I couldn't help but be amazed at how detailed and accurate most of the maps were. I also have a small fascination with "old" maps in general and ancient exploration.
That said, how did these explorers chart such detailed maps? Did they employ the services of a special cartographer who would document every book and cranny of a new land?
Thanks!
Hi, hopefully one of the historians of cartography will be able to answer your specific questions, but meanwhile, you may find this section useful:
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To get into any detail, it would be helpful to know what explorers or "new lands" you're referring to. But let me try to give some synthesis:
Mapmaking was (and still is) a process of repeating the confirmed knowledge of the world, and adding new information that you have learned or had reported to you. As we've discussed in the past, it's a relatively simple matter to determine your latitude from the position of the sun or stars. Longitude was more complex, and required invention of the chronometer to be easily done. But once those techniques were available, mariners—who can move about easily and have a strong interest in getting back home while not running into stuff—were able to chart the coastlines of the world pretty accurately.
The interior of continents is more difficult, complicated by terrain and vegetation, plus the challenges that disease, animals, and native populations pose to overland travelers. But by the 17th century, Jesuit missionaries were taught mapmaking skills, and could cobble together a few latitude/longitude readings with their observations about river or coastline shapes, sightings of mountains, knowledge of drainage patterns, and conversations with natives to sketch the country they explored. Though those observations sometimes were kept secret for political reasons, most eventually became part of the body of knowledge cartographers had about the world, and the blank spaces within continents began to have more and more detail—sometimes accompanied by a healthy bit of conjecture.
The next development in mapping was triangulation, but this is a time-consuming and labor-intensive process that can only be undertaken by those administering a nation, not by travelers exploring it. Triangulation creates a network of known points scattered across an entire nation whose latitude-longitude is accurately established, and this was well under way in many European nations by the 19th century. From those known points, often mountain peaks or other things visible from a distance, you can use simple compass bearings to fill in the spaces in between with a little less accuracy but much greater speed, and map the entire nation in detail.
I'm curious about maps not in the FAQ (well, FAQ thread titles: What methods did the Polynesians use?