How to Calculate Antipode

Many of us were warned as children that if we kept digging a hole we would exit through China. Unfortunately, there were a number of geological and geographic technical issues to overcome--including that China is the destination only if we live in parts of Argentina or Chile. To determine our exit, we need to calculate antipodes. Antipodes are points exactly opposite on the surface of the Earth. If a line was passed from the surface of the Earth through the center and out the other side, the points on the surface that are intersected by the line are antipodes. For most of the United States, the whole we dug would have emerged underneath the Indian Ocean, far from any land.
How to Calculate Antipode


Difficulty: Easy

How to:

Things You’ll Need:


  • World Map or Atlas
  • GPS device
Step 1
Determine the latitude and longitude of your first location using an atlas, GPS or reference list. For example, the coordinates of Central Park in New York City are 40° 47' N, 73° 58' W.
Step 2
The distance above and below the equator for the antipodes is the same, so the degrees latitude does not change. Only the North-South designation will change. To understand this conceptually, realize that the North and South Poles are antipodes to each other each lying at 90° N and 90° S, respectively. Any point on the equator has a latitude of 0° and its antipode would also lie on the equator with a latitude of 0°. Using the previous example, the latitude of Central Park is 40° 47' N, so the antipode for Central Park is 40° 47' S.
Step 3
Subtract 180 degrees from the longitude. This will flip the East-West or +/- designation of your longitude. Continuing the Central Park example, we subtract 180° from 73° 58' W to determine the antipode longitude of 106° 2' E.
Step 4
Locate the new coordinates on an atlas or map. The antipode of Central Park is then found to lie in the Indian Ocean, more than 1,000 miles southwest of Perth, Australia.

Article Written By David Chandler

David Chandler has been a freelance writer since 2006 whose work has appeared in various print and online publications. A former reconnaissance Marine, he is an active hiker, diver, kayaker, sailor and angler. He has traveled extensively and holds a bachelor's degree from the University of South Florida where he was educated in international studies and microbiology.

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