When I'm at the beach, gazing at the ocean, I start thinking about the people I know on the other side of it. I imagine looking all the way across the Atlantic to my friends in Europe when I'm on the Jersey shore, or trying to see to Japan across the Pacific from California.
But it turns out this is impossible — not because my eyesight is weak, but because my geography is totally wrong. When I stand and face the Atlantic in New Jersey, it turns out I'm actually looking toward South America, or maybe Africa, but definitely not Europe.
A new set of mind-bending maps from cartographer Andy Woodruff at Axis Maps shows what you'd really be seeing if you had perfect, ocean-spanning eyesight — or, to think about it another way, where you would end up if you started swimming away from the shore in a perfectly straight line.
It turns out that it's not as simple as facing Europe on the East Coast and Asia from the West Coast.
If you want to look at Europe, the place to be is not New Jersey. The bright points on the map show where you would need to stand, or start swimming, for a straight line to reach Europe first:
This happens for two reasons, Woodruff writes: Coastlines are jagged, and the Earth is round.
A straight line on the globe isn't what you think
When I'm standing on the coast of New Jersey and looking east, I assume I'm looking at the Portuguese coast, on the other side of the Atlantic on the 39th parallel. That idea is based on maps like these, which tell you which parts of the coastline on opposite sites of an ocean are at the same latitude. New Jersey is about the same amount north of the equator as Spain and Portugal.
But when I place my feet so that my toes touch the waves and look straight ahead, I'm not looking straight east, tracing the line of latitude. Because of the way the shoreline is angled, I'm actually looking southeast.
And that's true of many places along the jagged coastline of the United States. Looking straight into the ocean doesn't usually mean looking in a perfect eastwardly or westwardly direction. Imagine the straight line heading out along the blue line reaching into the ocean on the map above, and you can see why you're not looking at Europe at all.
The second part is a bit more complicated, but it explains why, if you could swim in a perfectly straight line from the coastline, you might not hit the land you think you will.
Maps are two-dimensional representations of a three-dimensional world. And the shortest straight line between two points on a globe isn't the same as the shortest straight line on a map. The shortest line on a globe, when you flatten it onto a map, looks like a curved, roundabout route.
Those curves are called "great circles," and they explain why when you fly from New York to Madrid, you don't just head straight out over the Atlantic, even though New York and Madrid are nearly directly across from each other by latitude. You head over Boston and along the coast of Nova Scotia instead:
That's why the lines on Woodruff's maps are curved — they represent the shortest distance between two points on a globe, not a map.
Here's where you have to stand to see Europe (or Asia or Africa)
Even if you think you know that two-dimensional maps do a bad job of representing a three-dimensional world, it can still be pretty mind-bending, something The West Wing did the best job of illustrating. ("You're probably wondering what all this has to do with social equality." "No, I'm wondering where France really is.")
So while it's hard to say exactly what you're looking at without knowing exactly where you're standing, from the East Coast it's more likely that you're looking at Africa than Europe. (The bright spots indicate where you can see Africa from, not where the lines end.)
You might also be seeing South America:
And from the Pacific, you could be looking toward Asia:
But it's equally possible you're looking at Australia:
Woodruff humbly admits, "I’m not entirely certain that I have all the math right, but I think it’s at least close. Even we cartographers sometimes have a shaky grasp of map projections and spherical geometry."
I plan to adjust my ocean gazing and waving at friends across the seas accordingly.