The northern Heritage Range, showing Patriot, Marble, and Independence Hills near the grounding line of the Filchner-Ronne Ice Shelf in the Weddell Sea. Ice and katabatic winds flow from the central dome of the West Antarctic Ice Sheet in the southwest around the nunataks. Stars show the possible location of glacio-poles for ice flow, accumulation and ablation measurements in the wider grid. GPR lines will run between these stakes where possible. The three boxes show the location of the detailed grids for stake networks and GPR profiling.