1.   The official zoning map of the City is hereby established and is made a part of this chapter by reference hereto.

   2.   The map shall be identified by the signature of the Mayor, attested by the City Clerk under the following words: “This is to certify that this is the official zoning map referred to by ordinance number 774 of the City of Grinnell, Iowa,” together with the date of adoption of the ordinance.

   3.   Regardless of the existence of purported copies of the official map which may from time to time be made or published, the official zoning map as certified above, together with amending ordinances, shall be final authority. The official map shall be on file in the office of the Clerk.

   4.   In the event that the official zoning map becomes damaged, destroyed, lost, or difficult to interpret because of use, the Council may by ordinance adopt a new official zoning map which shall supersede the prior official zoning map. The new official zoning map may correct drafting or other errors or omissions in the prior official zoning map, but no such correction shall have the effect of amending the original zoning ordinance or any subsequent amendment thereof. The new official map shall be identified by the signature of the Mayor attested by the City Clerk, under the following words: “This is to certify that this official zoning map supersedes and replaces the official zoning map adopted May 16, 1977, as part of ordinance number 774 of the City of Grinnell, Iowa.”