The Council may on its own motion or on petition after public notice and hearing by the Council as provided by law (See Code of Iowa Section 414.4), and after report by the Commission, amend, supplement or change the boundaries or regulations herein or subsequently established. Any owner or owners of property may present a petition duly signed and verified, requesting an amendment, supplement or change in the regulations prescribed for a district or part thereof. Amendments, supplements, or changes of the boundaries of districts as shown on the official zoning map shall be made by ordinance. The amending ordinance shall refer to the official zoning map and shall set out the identification of the area affected by legal description and identify the zoning district as the same exists and the new district designation applicable to said property. The Commission shall make a report to the Council within 60 days from the date of receipt of such petition. In case the proposed amendment, supplement or change is disapproved by the Commission, or in case of a protest against any proposed amendment or change signed by the owners of 20 percent or more, either of the area of the lots included in such proposed change, or of those immediately adjacent in the rear thereof, extending the depth of one lot or not to exceed 200 feet therefrom, or of those directly opposite thereto, extending the depth of one lot or not to exceed 200 feet from the street frontage of such opposite lots, such amendment shall not become effective except by the favorable vote of at least four-fifths of all the members of the Council. Said ordinance shall, after adoption and publication, be recorded by the Clerk as other ordinances and a certified copy thereof attached to the official zoning map. Such amendatory ordinance shall, however, not repeal or re-enact said map, but only amend it. The official zoning map, together with amending ordinances, shall be the final authority as the current zoning status of land and water areas, buildings, and other structures in the City. (See EDITOR’S NOTE at the end of this chapter for ordinances amending the zoning map.)