- "If your actions inspire others to dream more, learn more, do more and become more, you are a cartographer."
– John Quincy Adams
- "Not all who wander are lost."
– J.R.R. Tolkien
The steady development of seafaring technology eventually allows creation of ships able to withstand the storms of the open seas. But it takes more than a hardy ship for a man to venture into the unknown, and the development of Cartography provides this last push which is needed. With a sextant in hand and a map on which to define its correct position, a sailor on a sturdy ship may finally go out in the ocean.
And so begins the Age of Exploration. The Caravel, the first ship of next-generation vessels, is developed; and even older vessels are updated so that they can brave the open seas. Even sea resources become more productive thanks to these new developments!
This is one of the most important technologies in the middle game! It not only unlocks the possibility to explore the rest of the world (because your ships can now enter Ocean tiles), but also naval melee units that are substantially stronger than earlier ships. Furthermore, it improves the Gold yield of Fishing Boats, as the fishermen can now chart the most productive portions of the water to increase the efficiency and profitability of their catch. Any civilization which isn't landlocked should consider rushing this tech, which is actually quite easy: you need Sailing, then Shipbuilding, then Buttress (in Gathering Storm), then Cartography.
Of course, this line of research will yield few economic or military benefits, so even a seafaring civilization will need to get some other have-tos before going for Cartography. And, it goes without saying that a landlocked civ won't need this for another era (you need the next tech in the tree, Square Rigging, to unlock the all-important Industrialization).
There is a fair amount of scholarly debate about how long the “science” of making maps has been around, since there's a fair amount of debate about what constitutes a map. The oldest “map” to have been discovered is a depiction of what may be local terrain features about Catal Huyuk in Anatolia, dated to the 7th millennium BC. But the first ink splatters that are definitely a map is the “House of the Admiral” wall painting dating to the Minoan civilization c. 1600 BC. Around the 4th Century BC, the Greeks and the Romans were making somewhat more portable maps. And Ptolemy produced his famous treatise on cartography, 'Geographia,' in the 2nd Century AD.
In ancient China, maps have been found dating back to the Qin dynasty, while cartography in ancient India seems to have been limited mostly to star charts of more use to priests than to travelers. During the Dark Ages, most Europeans barely knew what was around the next bend in the river, much less over the horizon. But the Arabs were producing marvelous atlases such as Muhammed al-Idrisi's Tabula Rogeriana in 1154 showing what was known of Africa, the Middle East, the Mediterranean, the Indian Ocean and even the Far East. His work remained the most accurate and far-reaching map collection for three centuries.
Until the Age of Exploration kicked off in the 1400s, Portuguese, Spanish, English, Dutch and French explorers and adventurers brought back crude sketches of coastlines and islands, and European cartographers started making innovative maps for those looking to plunder distant shores. In 1492 the German Martin Behaim made the first known globe of the earth; in 1527 the Portuguese map-maker Diego Ribero made one with an equator. And where they didn't know what was there, these artists filled the empty spaces with sea monsters, mermaids, and all sorts of mythical and mythological creatures. So, if not as accurate, at least the maps were a lot more entertaining than those staid computer-generated ones created from satellite imaging, remote sensing and aerial photography these days.