But what if you wanted to go somewhere in particular? Like McMurdo Station, or someplace even more hospitable. How would you get there? Simple. You'd go north. Yes, yes, but WHICH north? Oh now we've run in to a little problem.
If you are given latitude and longitude for a location, most people who have a modicum of intelligence could correctly point to it on the map. If they were asked to provide a direction between points A and B they'd also probably be able to so. For instance, to get from A to B travel east from A for 100 miles etc... You can't go east at the South Pole though...
The US Navy has a solution to this. They call it Grid Mapping. They choose a line of longitude running through the South Pole and pretend that direction is north. All the other cardinal points are assumed to be the same as normal (ie: east is 90 degrees to the right of north etc...)
So now you can find your way back home. All you have to do is pull out your trusty compass... oh wait...