The boundaries of the zones provided herein are established and shown on a certain map which is designated the official zoning map, which is on file by ordinances in the office of the city clerk, and said map and all subsequent annexations and all amendments as may be made are hereby declared to be a part of this title. All zones and boundaries thereon provided are hereby confirmed, and all notations, references and other information shown thereon are declared to be a part of this title. All subsequent changes in boundaries of zones shall be made according to law and by ordinance and when so made and designated on said map, then said changes shall be effective and by reference shall become a part of this title. (Ord. 431, 10-24-2002)