The corporate limits shall be those existing at the time of ratification of this Charter, as set forth on the official map of the City and as they may be altered from time to time in accordance with law. An official map of the city, showing the current municipal boundaries and the boundaries of the wards therein, shall be maintained permanently in the office of the City Clerk and shall be available for public inspection. Upon alteration of the corporate limits or wards pursuant to law, the appropriate changes to the official map shall be made and copies shall be filed in the office of the Secretary of State, the appropriate office of the Register of Deeds, and the appropriate board of elections.