(a)    Content. The Council shall adopt, and may from time to time modify, a comprehensive plan setting forth in graphic and textual form policies to govern the future physical growth and development of the City. Such plan may cover the entire City and all of its functions and services or may consist of a combination of plans governing specific functions and services or specific geographic areas which together cover the entire City and all of its functions and services.
   (b)    Adoption. Upon receipt from the City Manager of a proposed comprehensive plan or proposed amendment of the plan, the Council shall refer such proposal to the City Planning Board, which shall within a time specified by the Council report its recommendations thereon. After receipt of the recommendations of the Planning Board, the Council shall hold a public hearing on the proposed comprehensive plan or amendment thereof and shall thereafter adopt it by resolution with or without amendment.
   (c)   Effect. The comprehensive plan shall serve as a guide to all future Council action concerning land use and development regulations, urban redevelopment programs and expenditures for capital improvements.