From Ptolemy to GPS, the Brief History of Maps

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Last spring, a 23-year-old woman was driving her car through the Ontario town of Tobermory. It was unfamiliar territory for her, so she was dutifully following her GPS. Indeed, she was so intent on following the device that she didn’t notice that her car was headed straight for Georgian Bay—so she drove down a boat launch and straight into the frigid water. She thankfully managed to climb out and swim to shore, as her bright red Yaris sank beneath the waves.

Accidents like this have become weirdly common. In Manhattan, one man followed his GPS into a park, where his car got stuck on a staircase. And in Europe, a 67-year-old Belgian woman was led remarkably astray by her GPS, turning what was supposed to be a 90-mile drive to Brussels into a daylong voyage into Germany and beyond. Amazingly, she just patiently followed the computer’s instructions, instead of relying on her own common sense, until she noticed the street signs were in Croatian.

You can laugh, but many of us have stopped paying attention to the world around us because we are too intent on following directions. Some observers worry that this represents a new and dangerous shift in our style of navigation. Scientists since the 1940s have argued we normally possess an internal compass, “a map-like representation within the ‘black box’ of the nervous system,” as geographer Rob Kitchin puts it. It’s how we know where we are in our neighborhoods, our cities, the world.

Is it possible that today’s global positioning systems and smartphones are affecting our basic ability to navigate? Will technology alter forever how we get around?

Most certainly—because it already has. Three thousand years ago, our ancestors began a long experiment in figuring out how they fit into the world, by inventing a bold new tool: the map.

One of the oldest surviving maps is, ironically, about the size and shape of an early iPhone: the Babylonian Map of the World. A clay tablet created around 700 to 500 B.C. in Mesopotamia, it depicts a circular Babylon at the center, bisected by the Euphrates River and surrounded by the ocean. It doesn’t have much detail—a few regions are named, including Assyria—but it wasn’t really for navigation. It was more primordial: to help the map-holder grasp the idea of the whole world, with himself at the center.

“There was something almost talismanic, I think, about having the world in your hand,” says Jerry Brotton, a professor of Renaissance studies at Queen Mary University of London who specializes in cartography. Indeed, accuracy wasn’t a great concern of early map-drawers. Maps were more a form of artistic expression, or a way of declaring one’s fiefdom. Centuries later, the Romans drew an extensive map of their empire on a long scroll, but since the map was barely a foot high and dozens of feet wide, it couldn’t be realistic. It was more of a statement, an attempt to make Rome’s sprawl feel cohesive.

The first great attempt to make mapping realistic came in the second century A.D. with Claudius Ptolemy. He was an astronomer and astrologer obsessed with making accurate horoscopes, which required precisely placing someone’s birth town on a world map. “He invented geography, but it was just because he wanted to do better horoscopes,” notes Matthew Edney, a professor of cartography at the University of Southern Maine.

Ptolemy gathered documents detailing the locations of towns, and he augmented that information with the tales of travelers. By the time he was done, he had devised a system of lines of latitude and longitude, and plotted some 10,000 locations—from Britain to Europe, Asia and North Africa. Ptolemy even invented ways to flatten the planet (like most Greeks and Romans, he knew the Earth was round) onto a two-dimensional map. What did he call his new technique? “Geography.”

After the Roman Empire fell, Ptolemy’s realistic geography was lost to the West for almost a thousand years. Once again, maps were concerned more with story­telling: A famous 12th-century map made by the Islamic scholar al-Sharif al-Idrisi—commissioned by his protector and patron, King Roger II of Sicily, a Christian—neatly blended Islamic and Christian cities together, while centering the world on (of course) Roger’s landholdings.

Other Christian maps cared even less about accuracy: They were mappaemundi, designed to show how the story of Christ penetrated the world. The most famous of these was made in Hereford, England—a massive 5- by 4-foot creation drawn on a single animal skin. Almost none of Europe, Asia or North Africa is recognizable, and strange wonders run amok: A lynx struts across Asia Minor (“it sees through walls and urinates a black stone,” the mapmakers note); Noah’s Ark is perched up in Armenia; Africa is populated by people with eyes and mouths in their shoulders.

At the top of the map—which faced east, the holiest direction—were pictures showing Adam and Eve tossed out of Eden, and Christ returning on the Day of Judgment. The map wasn’t intended to get you from town to town. It was designed to guide you to heaven.

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History’s Most Misleading Maps

Today’s high-tech devices aren’t the only tools leading voyagers astray. And some “mistakes” were made deliberately.

The Island of California 

(Map Company Limited)

An early Spanish explorer, possibly confused by the Baja Peninsula, reported in the 16th century that California was surrounded by water on all sides. This error was enshrined by the Amsterdam mapmaker Michiel Colijn in 1622, and California was drawn as an island well into the 18th century. 

As the Renaissance dawned, maps began to improve. Commerce demanded it—ships were crossing oceans, and kings engaged in empire-building needed to chart their lands. Technology drove maps to greater accuracy: The advent of reliable compasses helped create “portolan” maps, which had lines crisscrossing the sea from port to port, helping guide sailors. Ptolemy’s ancient work was rediscovered, and new maps were drawn based on his thousand-year-old calculations.

Indeed, Christopher Columbus’ discovery of America was partly due to Ptolemy—and errors in his cartography. Columbus carried a map influenced by the ancient Roman’s work. But Ptolemy thought the world was 30 percent smaller than it actually is; worse, the mapmaker was using Arabian miles, which were longer than Italian ones. Together these mistakes led Columbus to believe the voyage to Asia would be much shorter. It was an early example of a GPS-like near disaster.

As sea trade increased, maps of the New World became better, at least the seacoasts and major rivers, places the beaver trade depended on. The inland of America was mostly a mystery; mapmakers often draw it as a big blank space labeled “terra incognita.”

“The coastlines were accurate, but they weren’t as concerned about the interiors,” notes John Rennie Short, a professor and cartography expert at the University of Maryland Baltimore County. “The rest is, like, Who knows? As long as you keep bringing the beavers, we don’t care.”

Sea voyages became easier after 1569, when Gerardus Mercator unveiled the single greatest innovation in mapping after Ptolemy: the Mercator Projection. A polymath who was equally skilled in engraving and mathematics, Mercator figured out the best trick yet to represent the surface of a globe on a map—by gradually widening the landmasses and oceans the farther north and south they appear on the map. This was a great aid to navigation, but it also subtly distorted how we see the world: Countries close to the poles—like Canada and Russia—were artificially enlarged, while regions at the Equator, like Africa, shrank.

This was becoming the cardinal rule of maps: “No map entirely tells the truth,” notes Mark Monmonier, author of How to Lie With Maps. “There’s always some distortion, some point of view.”

Indeed, everyday people were realizing that a map was an act of persuasion, a visual rhetoric. In 1553, gentry in Surrey, England, drew a map of the town’s central fields, to prove these were common lands—and that villagers thus should be allowed to graze animals there. The map, they wrote, would allow for “the more playne manifest and direct understondying” of the situation. Maps, says Rose Mitchell, a map archivist at the National Archives of the U.K., were “used to settle arguments.” Meanwhile, educated people began collecting maps and displaying them “to show off how knowledgeable they were,” she adds. Even if you couldn’t read the words on a map from a foreign country, you could generally understand it, and even navigate by it. The persuasive power of a map was its glanceability. It was data made visual.

Maps weren’t just symbols of power: They conferred power. With a good map, a military had an advantage in battle, a king knew how much land could be taxed. Western maps showing Africa’s interior as empty—the mapmakers had little to go on—gave empires dreamy visions of claiming Africa for themselves: All that empty space seemed, to them, ripe for the taking. Maps helped propel the depredations of colonialism, as Simon Garfield argues in On the Map.

The United States after Lewis and Clark showed Americans just how much West there was to be won. Mind you, their trip was hellish: Previous maps were so vague they showed the Rockies as a single mountain range. “So they thought they were just going to cruise up to it, go over the top, and pop their canoes back in the river and go all the way to Pacific,” laughs David Rumsey, who created Stanford’s map collection in his name. “And it was a bloody nightmare, up and down, up and down.”

Maps were so valuable that seafarers plundered them. When the 17th-century buccaneer Bartholomew Sharp captured a Spanish ship, he exulted over his cartographic haul: “In this prize I took a Spanish manuscript of prodigious value,” he later wrote. “It describes all the ports, harbors, bayes, Sands, rock & rising of the land....They were going to throw it over board but by good luck I saved it. The Spanish cried when I gott the book.”

By the late 19th century, the surge in mathematic reasoning and measurement technology made mapmaking explode. In France, the Cassini family crisscrossed the country to calculate its dimensions with precision never before seen. Their trick? Using “triangulation”—a bit of trigonometry—to let them stitch together thousands of measurements taken by peering through the new, high-tech “theodolite.” Breakthroughs in binocular lenses allowed surveyors to measure scores of miles at a glance. World maps became increasingly accurate.

Local mapping became deeply granular. The British Ordnance Survey began mapping the U.K. down to the square yard, and the German entrepreneur Karl Baedeker produced similarly nuanced maps of European cities. Tourists could now confidently tour foreign realms, their annually updated guides in hand, able to locate individual buildings, much like today’s citizens peering at Google Maps on their phones. Being prominent on a local map was valuable to merchants, so mapmakers in the U.S. sold the rights. “If you paid more, you’d get your building cited,” Short notes. “It was like advertising.”

Maps could change the way people understood the world around them. In the 1880s, the social reformer Charles Booth produced a moral map of London, with houses color-coded by income and—in Booth’s shaky calculations—criminal tendencies. (Areas colored yellow were “wealthy,” while black ones were “Lowest class. Vicious, semi-criminal.”) Booth wanted to help aid the poor by showing geography was tied to destiny, but his techniques wound up reinforcing it: in the U.S., banks began to “redline” poor neighborhoods, refusing to loan money to anyone in their precincts.

By the 20th century, maps helped win the Second World War. Winston Churchill fought with guidance from his “map room,” an underground chamber where up to 40 military staffers would shove colored pins into the map-bedecked walls; Churchill adorned his bedroom wall with a huge map showing Britain’s coast, constantly visualizing in his mind how to defend it against invasion.

These days, our maps seem alive: They speak, in robotic voices, telling us precisely where to go—guided by the satellites and mapping of companies like Waze, Google, Bing and Mapquest. “There’s something fun about turn-by-turn directions,” says Greg Milner, author of Pinpoint: How GPS Is Changing Technology, Culture and Our Minds. “It’s very seductive.” There’s no need even to orient yourself to north: The robot voice tells you to turn right, turn left, with you always at the center.

Milner worries, though, that GPS is weakening something fundamental in ourselves, corroding not just our orientation skills, but how well we remember the details of the world around us. A 2008 study in Japan found that people who used a GPS to navigate a city developed a shakier grasp of the terrain than those who consulted a paper map or those who learned the route via direct experience. Similarly, a 2008 Cornell study found that “GPS eliminates much of the need to pay attention.” Some map historians agree that a subtle change is at hand. Short tells me that he likes the convenience of GPS-brokered directions—“but what I do lose is the sense of how things hang together.”

Rumsey isn’t convinced of this loss, though. As he argues, the convenience of GPS and online mapping means we live in an increasingly cartographic age. Many online searches produce a map as part of the search results—for a local store, a vacation spot, live traffic updates before heading home. People today see far more maps in a single day than they used to, Rumsey notes: “The more you interact with maps, the more agile you become. Maps beget more maps.” When Rumsey first started collecting and displaying maps in the 1970s, people said, Why bother? These are old and out of date; who cares? Now when people visit his collection at Stanford they “get it right away. That’s because they’ve been exposed.”

It’s possible both effects are true. When I decide to order some takeout, my phone will—like a robot Baedeker—generate a map of local places that are open. It’s true that if I walked to one, I’d just numbly be following zigzagging turn-by-turn directions. But on the other hand, I look at that little gustatorial mappamundi of my neighborhood pretty often; I could probably draw it from memory by now.

Technology hasn’t changed some of our oldest urges. The historian Brotton once visited Google, where the engineers showed him a huge, wall-sized version of Google Earth. They asked him, whenever a visitor shows up to try it out, what’s the first thing they zoom in to look for? Their own home.

“They go, wow, look at that!” Brotton says. It’s the same perspective as the people who held that Babylonian clay tablet nearly three millennia ago: using a map to figure out where, exactly, we stand.