Area Hierarchy Addressing 2 2.1 2.2 222 1.2 22 121 1.22 3.1 3.2 2021/1/31Area Hierarchy Addressing 2021/1/31 6 1 2 3 1.1 1.2 2.1 2.2 3.1 3.2 2.2.1 2.2.2 1.2.1 1.2.2