Each city of the metropolitan class is authorized and required to prepare a plan for the future physical development and growth of the city. Such plan shall be prepared and shall be carried out by an appropriate city board or official. The plan may include such lands outside the corporate limits of the city as may bear a relation to the development of the city. A planning board may be given such other powers and duties by statute or charter as may be appropriate. On or after January 1, 1998, the planning board shall have one member qualified and appointed as provided in section 14-373.02.