The corporate limits of the Town shall be those existing at the time of ratification of this Charter, as the same are set forth on the official map of the Town, and as the same may be altered from time to time in accordance with law. An official map of the Town, showing the current Town boundaries, shall be maintained permanently in the office of the Town Clerk, and shall be available for public inspection. Immediately upon alteration of the corporate limits made pursuant to law, the appropriate changes to the official map of the Town shall be made.