Where do directions come from?


So. Depending on where you are in the world there is a geologically direction. The Eastern Hemosphere. The Western Hemosphere. The middle east. So on so on. So what I wanna know is what exactly do these places start? Like where is the center? I know country to country it will be different. Like Texas is the Midwest in America but I’m sure it’s not the Midwest of the planet. Where do these places start geologically? Specifically for Earth and the US.

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So magnetic north occurs naturally and we have compasses to point to it. With that bearing we can establish the rest of the cardinal directions. And we’ve known about this for a long, long time.

“Hipparchus, a Greek astronomer (190–120 BC), was the first to specify location using latitude and longitude as co-ordinates. He proposed a zero meridian passing through Rhodes.”

“In 1884, at the International Meridian Conference in Washington, D.C., 22 countries voted to adopt the Greenwich meridian as the prime meridian of the world.”

From that point on the world pretty much locked in it’s definitions of eastern and western based on the official new Prime Meridian. And that’s how Texas wound up being in Midwest of the Western Hemisphere.

The prime meridian is through Greenwich UK, you could see everything left of it as west.

The equator is the border between North and South that’s pretty obvious.

For north and south the center is the equator, the midpoint between the two poles – and the poles are the points around which the earth rotates.

There’s no natural centerpoint for west and east though, so this one is pretty much made up – for stuff like “the middle east” it’s based on Europe. Asia was the far east and the thing in the middle was, well, Middle east.

The eastern and western hemispheres are based on the Greenwich meridian, which is again a made up centerpoints that goes trough an old observatory near London. Everything west of that point is the western hemisphere and the same for east.

For the US it’s simply based on the middle of the country.

Directions are all relative, it’s based on perception.

The equator and prime meridian are generally regarded as the way to divide into hemispheres (north/south and east/west)

Typically we understand the center to be the international date line. That tells us, basically, what day is what. The other center, the one we use (still?) for navigation is the Greenwich meridian. West from there is west until you hit the IDL, east from there is east until you hit the IDL.

The mid point would be 90 degrees east or 90 degree west of Greenwich; here is a map with an example.