Calculate Antipode
Geographers define antipode as a point exactly opposite a reference point on the opposite side of the earth. To calculate the latitude of an antipode, change the sign and direction of the latitude of the reference point. To calculate the longitude of an antipode, subtract the absolute value of the reference-point longitude from 180 degrees and change the sign and direction of the answer with reference to the reference point.
Instructions
Example Calculation
1. The latitude and longitude of Tampa International Airport (TPA) are +27.97 degrees north and -82.53 degrees west.
2. To calculate the latitude of the antipode, change the sign and direction of TPA's latitude. The answer is -27.97 degrees south latitude.
3. To calculate the longitude of the antipode, subtract the absolute value of TPA's longitude from 180 degrees, and change the sign and direction of the answer to the opposites of the reference point. The answer is +97.47 degrees east longitude.
4. The latitude and longitude of the antipode to TPA are -27.97 degrees south latitude and +97.47 degrees east longitude, a point in the Indian Ocean west of Australia.
Tags: change sign, change sign direction, reference point, sign direction, longitude antipode, absolute value
