Compass directions

North, east, south and west are the four main directions.

They help us say which way to go. Stand up and point north. Now turn and point to each of the others.

North, east, south and west are called the cardinal directions. They are the main points of the compass, and they are often written with just their first letters: N, E, S and W.

East and west are at right angles to north and south. If you face north, east is to your right, west is to your left and south is behind you. Ordnance Survey, Britain's national mapping agency, suggests a rhyme to remember the order going clockwise from north: Naughty Elephants Squirt Water.

The four cardinal directions are the primary points of the compass: north, east, south and west, abbreviated N, E, S and W. National Geographic Education describes east as lying in the clockwise direction from north, with west directly opposite east; east and west sit at right angles to north and south.

Directions matter because left and right depend on which way you are facing, while north does not. Two people facing each other have opposite lefts, but they share the same north. That is why maps, hiking guides and navigation all use compass directions to describe where things are and which way to travel. Memory aids help: Ordnance Survey offers "Naughty Elephants Squirt Water" (or "Nobody Ever Swallows Whales"), and National Geographic suggests "Never Eat Sour Watermelon."

Some ways are in between.

Halfway between north and east is northeast. There is also southeast, southwest and northwest.

Sometimes the way you want to go is not exactly north, east, south or west. Halfway between two cardinal directions there is another direction, named after both of them: northeast, southeast, southwest and northwest.

Ordnance Survey's map-reading guide puts it simply: if you are walking halfway between two points of the compass, you can say you are heading north-east, south-east, south-west or north-west. North or south always comes first in the name.

The directions halfway between the cardinal points are called ordinal or intercardinal directions: northeast (NE), southeast (SE), southwest (SW) and northwest (NW). A compass rose that shows all eight gives a much finer way of describing a route than four directions alone.

In the names, north or south always comes first: we say northeast, never "eastnorth." Ordnance Survey's map-reading guide uses these general directions in its exercises, asking which way a walker is heading between numbered points on a map; one answer in its own key is south-west. Learning to name these eight directions is a first step toward reading any map's compass rose.

In the morning, the Sun comes up in the east.

In the evening, it goes down in the west. Never look right at the Sun. Just notice where it is.

You can find east and west without a compass if you know roughly what time of day it is. In the morning, the Sun rises roughly in the east and climbs higher. In the evening, it sets roughly in the west.

National Geographic Education has young children check where the Sun is first thing in the morning and again at the end of the school day, for five days, and look for the pattern. (Never look straight at the Sun; just notice which side of the sky it is on.)

The Sun's position can be used to find east and west if you know the general time of day: it rises roughly in the east and sets roughly in the west. NASA's StarChild site explains why. The Sun is not traveling around us; Earth spins toward the east, carrying you with it, so whatever lies beyond your eastern horizon comes into view. That is why the Sun, the Moon, the planets and the stars all rise in the east and move westward across the sky.

The word "roughly" matters: National Geographic Education is careful to say the Sun rises roughly in the east, so it is a guide to general direction, not a precise one. National Geographic Education adds another clue for snowy places: in the Northern Hemisphere, snow melts faster on the south side of buildings.

Many maps have north at the top.

A little arrow or a star shows the ways. Look for the N. That shows north.

To use directions on a map, you need to know which way the map is facing. Many maps have a compass rose, a drawing that shows the directions, or a single arrow that points north. Many maps are printed with north at the top, so east is to the right, south is at the bottom and west is to the left.

Not every map does this, so always check the arrow. Ordnance Survey says its own maps are always printed with north at the top of the sheet.

A compass rose shows how a map lines up with real directions. Simple ones show the four cardinal points; more elaborate ones add the ordinal directions between them. Britannica Kids notes that in many cases maps are printed so that north is at the top, which puts east on the right and west on the left.

It is a convention, not a law of nature, so the compass rose or north arrow is worth checking on any map you pick up. Some mapmakers commit to it: Ordnance Survey states that its maps are always printed with north at the top of the sheet. Once you know the orientation, you can turn the map until its north matches north on the ground, and then the roads and rivers on the paper point the same way as the real ones.

A compass has a needle that can spin.

The needle points north. Then you can find east, south and west too.

A compass has a needle that can turn freely. It lines up with Earth's magnetic field and points toward magnetic north. Once you know where north is, you can find all the other directions.

Magnetic north is not quite the same as true north, the direction of the North Pole at the top of the globe. The difference between them is an angle called magnetic declination. It is different from place to place and changes over time, so careful map readers look it up.

A magnetic compass points toward magnetic north. NOAA's National Centers for Environmental Information define magnetic declination (sometimes called magnetic variation) as the angle between magnetic north and true north. Declination is positive when magnetic north lies east of true north and negative when it lies west, and it changes both with location and over time.

Because compasses point toward magnetic north, a navigator needs the local declination to find true north. NOAA gives the rule: add the declination to a magnetic bearing to get the true bearing, counting west as negative. NOAA also corrects a common idea: the needle does not point at a single spot called the magnetic pole. It follows the horizontal direction of Earth's magnetic field where the compass is.

We can use directions to help a friend.

"Walk five steps north." "Now walk three steps east." Can your friend find the hidden toy?

Directions let you explain where something is in a way that works for everyone. Instead of "over there," you can say "the park is north of the school" or "walk three steps to the south."

National Geographic Education suggests a game: hide an object, then guide a friend to it using only directions and steps, such as "walk five steps to the north." Playing Simon Says with directions is good practice too. On a map, you can describe a trip the same way: "Go east along the river, then north up the hill."

Compass directions turn vague descriptions into instructions anyone can follow. "The lake is northwest of the town" means the same thing to every reader, wherever they are standing. Combining a direction with a distance (three steps south, 2 kilometers northeast) describes a route completely, which is the basic idea behind following a map on foot.

For exact positions, maps add grids. Ordnance Survey maps are covered with numbered grid lines: eastings increase toward the east and northings toward the north, and its guide tells readers to go "along the corridor" (east) before going "up the stairs" (north). Worldwide, latitude measures how far north or south a place is and longitude how far east or west, so the same direction words underpin every global coordinate.