In Halves of the World you split the world in half two ways. Now the letters in a place's coordinates tell you exactly which halves it is in.
Key idea
N or S in the latitude gives the Northern or Southern Hemisphere. E or W in the longitude gives the Eastern or Western Hemisphere. Every place (not on the lines themselves) is in one of each.
Worked example: Sydney
Sydney, Australia, is at about 34° S, 151° E. Which hemispheres is it in?
- The latitude letter is S: Southern Hemisphere.
- The longitude letter is E: Eastern Hemisphere.
Answer: The Southern and Eastern Hemispheres.
Why it works
The Eastern and Western Hemispheres are split by the prime meridian (0°) and the 180° meridian. The prime meridian runs through London and western Africa, not along the edge of the Atlantic. So everything west of Greenwich, including Portugal, Ireland, most of Spain and much of West Africa, is in the Western Hemisphere.
Worked example: A surprise
Dakar, Senegal, in Africa, is at about 15° N, 17° W. Which hemispheres?
- Latitude 15° N: Northern Hemisphere.
- Longitude 17° W: Western Hemisphere, even though Dakar is in Africa.
Answer: The Northern and Western Hemispheres.
| Hemispheres | Letters | Example |
|---|---|---|
| Northern and Western | N and W | New York, about 41° N, 74° W |
| Northern and Eastern | N and E | Tokyo, about 36° N, 140° E |
| Southern and Western | S and W | Buenos Aires, about 35° S, 58° W |
| Southern and Eastern | S and E | Sydney, about 34° S, 151° E |
Common mistake
Thinking the Western Hemisphere means "the Americas" and the Eastern means "Asia." Use the letters, not the continent: Lisbon (39° N, 9° W) and Accra, Ghana (6° N, 0.2° W) have W longitudes, so they are in the Western Hemisphere. And eastern Russia and some Pacific islands reach past 180°, into the Western Hemisphere.