Grid north is a navigational term referring to the direction northwards along the grid lines of a map projection. It is contrasted with true north (the direction of the North Pole) and magnetic north (the direction of the Magnetic North Pole). Many topographic maps, including those of the United States Geological Survey and the Ordnance Survey, indicate the difference between grid north, true north, and magnetic north.
At the South Pole, grid north conventionally points northwards along the Prime Meridian.[1]