# When I travel next, I want to reach the point on the earth that is exactly opposite my home, how can I discover where that is?

My wife and I are planning to travel to Japan next September (we are from Brazil). Since I was a child I have known that if I made a hole (a big one) straight down, I would reach Japan. Well, as the time passes every time I look at the ground, I imagine that far, far away there it is, Japan. Now that I'm going to Japan, I would like to know for curiosity (and to perhaps reach this place in my travels), the exact point in Japan that represents the place that, if I could dig a very big hole directly down from my house in Brazil, I would find in Japan.

So, is there some tool online that could help me? Is there some way to easily find this place using my home coordinates?

• This question appears to be off-topic because it is about geometry, not travel. It might be better at math.stackexchange.com. Commented May 1, 2014 at 13:49
• @NateEldredge I disagree. The antipode of my address is on my bucketlist
– user141
Commented May 1, 2014 at 13:55
• You can reach literally anywhere depending on the angle you're digging at. Commented May 1, 2014 at 14:25
• @gerrit sure, but he asked for 'exactly otherside'(sic) - not any old angle. Commented May 1, 2014 at 14:28
• I'm still upset I didn't go to the small town in Spain directly opposite Christchurch, New Zealand :/ Commented May 1, 2014 at 14:28

It's very easy, and a quick google search for 'antipode' and 'map' will find sites that find it for you.

For example, Antipodes Map either detects your location, or you can enter one, and it'll show you on a zoom-able map where your antipodal destination is.

Unfortunately as shown by the map above, only about 15% of land territory is antipodal to other land, and only a tiny fraction of Brazil is antipodal to Japan (in fact, to the islands of Okinawa and Amami). A rather larger amount of Brazil (but still a small fraction of the country as a whole) is antipodal to the Philippines and Indonesia, along with Brunei, parts of Malaysia and the South Korean island of Jeju. Without knowing your exact location I can't be sure where it ends up. I'll leave that last step up to you to investigate!

Another "Map Tunneler" site shows it quite nicely side by side. I can click and zoom in on New Zealand and the other window zooms in at the same time to show me northern Spain - the antipode.

• Antipodes Location: Most likely the ocean. Watch out for sharks. Unfortunatelly, I wont be able to reach the point :(... Commented May 1, 2014 at 14:48
• Better not dig the hole, then. You'll flood your home! Commented May 2, 2014 at 13:08
• If your antipode is in ocean and you intend to visit it anyway, do so in a boat so as to be safer from the sharks. Commented May 4, 2014 at 7:37
• Note that Australia is the "Bermuda Triangle" of the Southern hemisphere. Commented Sep 15, 2014 at 14:59
• Here's a slightly bigger tool: ubasics.com/dighole Commented Apr 21, 2015 at 16:00

Yes the lat/lon coordinates are your friend. Lets assume the following coordinates are yours: S 9° 17' 42", W 51° 19' 17". You are 9 degrees south of the equator. Your antipode will be 9 degrees to the North. Just replace the S by the N and you have the latitude of your antipode (N 9° 17' 42'').

You are 51° 19' 17" away from the Greenwich line. Which mean 51 degrees, 19 minutes and 17 seconds. 1 degree contains 60 minutes and 1 minute contains 60 seconds. To get the longitude of your antipode, you'll need to do a bit more math. The antipode will be 51° 19' 17" away from the 180° longitude. To get the longitude which is relative to the Greenwich line, you need to subtract your longitude from the 180 line. It will become E (180-51)° (60-19)' and (60-17)''

``````180    0     0
51   19    17
``````

You don't want to have negative minutes and seconds, so you borrow a degree and subsequently a minute:

``````179   59    60
51   19    17
===============
128   40    43
``````

It appears that the antipode of the center of Brazil is close to the Philippines.

There are a multitude of online calculators to identify your antipode just google search for them, but I prefer the pencil paper calculation due to its simplicity. Also using a calculator without explanation on how the location is derived feels like falling for tourist traps ;)

• Given that you probably have to use the internet to find your own latitude and longitude, using pencil and paper seems way more complicated than just doing the whole thing online. Commented May 1, 2014 at 16:30
• Yes, doing it by hand is insane and way way more complicated. It is also really cool though! ;-)
– Ant
Commented May 1, 2014 at 16:34
• @DavidRicherby Nah a gps unit suffice
– user141
Commented May 1, 2014 at 18:09
• @andra: The answer may look great and you may prefer the pencil paper calculation, but it is obviously not that simple, since your calculations are wrong. The correct longitude is E 128° 40′ 42.168″. Commented May 1, 2014 at 21:39
• @Tor-EinarJarnbjo Oops I forgot to consider the minutes and seconds. Thanks for noting I edited my answer and provided the full calculation. For you it might not look simple, but now you have the provenance ;)
– user141
Commented May 2, 2014 at 7:57

Use the Map Tunneling Tool. Unfortunately you won't reach any islands in Japan unless you live close to the Uruguay border.

Find a globe. Put your arms out front with the forefingers pointing in. You are now a human calliper. Bring the arms together to nip the globe such that the left finger touches home. The right finger is now on the target.

Rotating the globe might help, unless you're a gymnast.

• For best results, use a globe whose diameter is the distance between your shoulders, so that your forefingers are parallel. Commented May 2, 2014 at 13:22
• NatGeo used to publish (I grew up with one purchased in the early 1970s) a globe that was sitting loose in a stand rather than bolted on at the poles. The stand had a ring that would match up to the equator if the globe was oriented with a pole directly up. That made it easy to visualize great circle paths by simply rolling the globe until the desired end points were both aligned with the ring. Finding Antipodal points was easy with it because the ring was also marked in degrees. Commented May 3, 2014 at 0:01
• That's going to be so staggeringly inaccurate as to be worthless. I doubt you could estimate the antipodal point to better than a thousand miles using that method. Commented May 3, 2014 at 11:56
• @DavidRicherby Accuracy suffers, but your odds of actually getting a piece of land increase exponentially and it's kid of fun which is probably the main point. Commented Mar 3, 2015 at 6:44

Wolfram Alpha could help here as well.

For example, typing in antipode of London, UK shows a map with a point south of New Zealand.

The Google Earth application makes this really easy, no searching or math required. Just choose tools->ruler. Zoom in on your home and click to begin measuring. Zoom out and rotate the globe until the ruler starts spinning around the globe in circles. Zoom in on that spot and keep moving the ruler until you're as close as you want to get, then note the coordinates.