AQUILA Magazine Earth Issue plus resources | Page 16

The very best way to look at the Earth ( assuming space travel is out of the question ) is on a globe , but even that ’ s not always practical . Globes are cumbersome and difficult to carry . They don ’ t fit in a backpack and if you drop them ( especially on a ship in the middle of the ocean ) they tend to roll . No . Flat paper maps are much easier to lug about , but they come with their own drawbacks . Imagine trying to cut up a globe and lay it out flat on a piece of paper . The first thing you will notice is that it is Very . Difficult . Indeed . The pieces need to be stre‐tched in order to lie flat , and wherever things are stretched , distortion occurs . In fact , it is impossible to be one hundred per cent accurate .

Are you saying all our paper maps are distorted ? some distortion is bound to happen . What we have ended up with instead are map projections . They ’ re mathematically organised around different rules , but they are all imperfect .

If that ’ s the case …

It is .

… then how do maps get people where they need to be ?

Imagine a grid on the Earth ’ s sphere . Latitude lines are circles going around the globe , horizontally . With the equator in the middle , they tell you how far up or down you are on the planet .

Longitude lines are semicircles that travel from the North Pole to the South Pole . They tell you how far around the world you are . If you know your latitude and longitude , you can pinpoint your location .

Latitude Longitude

Now imagine you are the captain of a ship .

Do I get a hat ?

Shh .

You choose a compass direction and set sail . If you sail directly north , south , east or west , you will circle the Earth and return to where you started ( ignoring all the land in the way ... and the fact that you have to remain on course at all times , ed ). If you sail in any other compass direction ( south-east , east-north-east etc ) you will travel around the Earth in a spiral-shape and end up at one of the poles . These lines are called loxodromes , or rhumb lines .

I am , yes . Mathematicians and cartographers have been trying to find the best way to do this since the 1500s ( although there are maps that date back much earlier than this ). No matter what ,

As spirally as these lines are , to sailors and compasses , they act as straight lines .

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