Oh, it's like the Grid Square system that Ham Radio operators use: https://en.wikipedia.org/wiki/Maidenhead_Locator_System https://en.wikipedia.org/wiki/Maidenh

Oh, it's like the Grid Square system that Ham Radio operators use: https://en.wikipedia.org/wiki/Maidenhead_Locator_System https://en.wikipedia.org/wiki/Maidenhead_Locator_System Just with a greater precision since it seems to go down to a very localized area, such as a building.