When we look at maps, what we see is not what we get. In 1569, Gerardus Mercator solved the problem that had forever vexed mapmakers: maps are flat and the Earth is round, more or less (technically, it’s an oblate spheroid). The biggest downside to the Mercator is what happens when you try to represent a three-dimensional reality in two: the farther you get from the equator, both north and south, the larger the distortion of the actual size of the landmasses. For fun, print a map on a regular 8½ by 11 sheet of paper (A if you’re a Brit) and try to wrap it around an orange or a tennis ball. Messy, ain’t it?
Your View of the World Is Horribly Skewed – and So Is Mine
The best solution is a globe but it’s really hard to fold
The Mercator Projection became a navigational standard because it used compass bearings, which are not the same thing as longitudes and latitudes.
Latitudes are imaginary horizontal lines
They have nothing to do with time but a lot to do with climate.* Latitudes run horizontally across the earth at its fattest point. When I looked for the <fattest point on earth>, the stern schoolmarm inside my computer jumped up and chided me for using hurtful language.**
Latitudes measure distance from the equator
It’s 0º at the equator. The pole up on top is 90º north and the pole on the bottom is 90º south of the equator. Which raises the question: If Santa’s workshop is at the North Pole, what’s going on at the South Pole?
Longitudes measure the distance east and west of the Greenwich Meridian
The Greenwich Meridian is the imaginary line that runs from the North Pole to the South Pole. You can draw any line from one pole to another. The one we use passes through Greenwich, London, England and was set as 0º longitude long ago.
Longitudes have to start somewhere
Everyone important agreed on using Greenwich as a starting point because it was where the Royal Observatory was. It’s useful to remember there’s a good bit of jingoism*** going on here, as this was when Britannia ruled the sea and owned properties around the world that were there for the taking. Brits argue that the Royal Observatory was the logical choice because it was highly-regarded for its astronomical and naval research and was already widely used as the world standard for timekeeping.
The real story involves the International Meridian Conference of 1884, held in Washington, D.C.
Up to that point, countries used their own reference points. Imagine the logistical nightmares for international trade, shipping, and timekeeping. In the end, Greenwich was chosen by a consortium of 26 major maritime countries.
After 100 years as the international prime meridian (zero degrees latitude), the world and Global Positioning Satellites now use the International Reference Median
It’s the global standard for zero longitude maintained by the International Earth Rotation and Reference Systems Service. It provides a precise reference for mapping, navigation, and timekeeping worldwide.
In case you missed it, the new Median is 5.3 arc-seconds east of the old one
An arc-second is one 3,600th of a degree out of the 360 degrees of the earth’s 21,600 mile circumference, meaning the new line is about the length of a football field away from the old.
What we see is not what we get
The Gall Projection Map is actually a cylinder. It accurately represents the sizes of continents and countries, but has to distort their shapes to do so. It is entirely divorced from navigational accuracy.
By showing the sizes of countries relative to each other, the map grossly distorts what we’ve been looking at since we were kids and Miss Reichenbach pulled down the map hanging over the blackboard
Some likened looking at Gall’s map to viewing oneself in a deliberately distorted fun house mirror.
So how do you project a sphere onto a plane?
It’s not easy because the world is curved and maps are flat, which is why we have globes. In 1970, Arno Peters caused a kerfuffle in the map-making community with his “Peters World Map.” Its real name is the Gall Equal-Area Projection.
Which difference in what’s there and what you’re used to seeing first grabs your attention?
For me, it was how ridiculously small India appears, especially when I know there are one and a half billion people crammed into one and a half million square miles. That’s about 1,000 people per square mile, or – get this – each person gets the same amount of space as a standard tennis court.
The second thing that struck me was how huge Africa is.
- It’s three times the size of the United States and my Mercator mind thought they were about the same size.
- Africa and Greenland appear to be the same size when we look at what they call the Mercator perception.
- But wait a minute. When we look at Gall Projection Map’s reality, we see Africa is 14 times larger than Greenland.
- Europe looks bigger than South America, but is really only half the size.
- Brazil and Alaska appear to us to be the same size, but Brazil is five times bigger.
If you want to see things where the area is correct, you have to live with distorted shapes
If you’re really interested, take a look at Tissot’s Indicatrix of Deformation, a new one on me. I “discovered” it because I took the time to rummage around and see what’s going on down deep.
Tissot’s Indicatrix is a tool that allows us to visualize how distortions happen when small circles are projected onto a map
For the math-inclined, the circles appear as ovals, what they called ellipses in geometry class
Draw a line from the center to anywhere on the circle and you get the same radius every time. Ellipses have a long radius and a short one. The bigger the difference, the loopier the ellipse.
The size and shape and size of those ellipses allow mapmakers cartographers to quantify the amount of distortion at any given location.
Having said all that
There is one sure thing we know: visual familiarity and spatial truth cannot exist harmoniously.
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*For more, see Buffett, James William, Changes in Attitudes, Changes in Latitudes.
**Lady, any planet that can stand billions of years earthquakes and volcanoes and tidal waves and I forget how many Ice Ages won’t be bothered by one little word taken out of context.
***An extreme form of nationalistic patriotism
Bonus
At least they kept things simple by agreeing that the meridian also be the location of the International Date Line, the boundary between one calendar day and the next. Just kidding. It’s on the other side of the planet.
The IDL runs (sorta) along the 180 degrees longitude in the Pacific Ocean
But it zigzags as much as gerrymandered voting districts to avoid the confusion of having physically close areas operating with different days of the week.
Key Takeaway
Learn to see what’s there, not what you expect to be there or what you think should be there.
Readers tell me they always find something new and often find things they thought were so but aren’t. When asked how I can keep doing this after more than 10 years and 500 articles, columns, and stories, I tell them the problem isn’t finding these things, it’s deciding where to stop. Everything I’ve ever come across looks different when I take the time to look deeper at things most of us just glide over. I set out to write 500 words about seesaws, and look what happened: 1,269 words on maps without even scratching the surface. I’ll probably finish seesaws in time for next Monday.
