Inquiring minds want to know

I saw an article in USA Today that reported one-quarter of the West Antarctic ice sheet has been classified as “unstable.” According to the article, the ocean water in front of the glacier is too hot, causing the underside to melt where it grinds against the seabed. This allows the glacier to slide more quickly into the ocean and to become thinner.

My question is: How does anyone know where West Antarctica is? Every direction from the South Pole is north. Once you are north of the South Pole, moving in a clockwise direction around the pole will take you eastward, just like it does in the rest of the world; counterclockwise will take you westward. Where’s the starting point? Obviously, “West” Antarctica is an agreed-upon arbitrary area.