----------------------------Original message---------------------------- THe opposite side of the world: Take a known Lat-Long. Latitude is the same, but North becomes South & vice-versa. Subtract your current longitude from 180, and swap east for west, or vice versa. This should do it... Thus Philly's antipodes is: 40*S, 104*47'E, in the Indian ocean SW of Australia. -- Nat Case Hedberg Maps, Inc. Publisher of PROFESSOR PATHFINDER Maps ___________________________________________________ Production Office (White River Jct, VT): [log in to unmask] Business and Sales Office (Minneapolis, MN): [log in to unmask]