The boundaries of the zones hereinabove designated shall be established and clearly marked upon that certain map identified by the approving signatures of the city council, marked and designated as the "zoning map", which map is now on file in the office of the city clerk-treasurer. Said map has been heretofore examined in detail by the city council and is adopted as a part of this title, but this title and said map shall be subject to change from time to time as may be determined by the city council, following procedures provided by law. (Ord. 499, 4-16-2009)