1.   Official Zoning Map. The City and surrounding unincorporated lands shall be divided into districts, as shown on the Official Zoning Map which, together with all explanatory matter thereon, shall be adopted by ordinance. One map shall identify the unincorporated and incorporated areas. If, in accordance with the provisions of this chapter and Chapter 414 of the Code of Iowa, changes are made in district boundaries or other matter portrayed on the Official Zoning Map, such changes shall be entered on the Official Zoning Map promptly after the amendment has been approved by the City Council, with an entry on the Official Zoning Map as follows:

No amendment of this chapter which involves a matter portrayed on the Official Zoning Map shall become effective until after such change and entry has been made on said map.

2.   Replacement of the Official Zoning Map. In the event that the Official Zoning Map becomes damaged, destroyed, lost, or difficult to interpret because of the nature or number of changes and additions, the City 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 Official Zoning Map or any subsequent amendment thereof. The new Official Zoning Map shall be identified by the signature of the Mayor, attested by the City Clerk, and bearing the Seal of the City under the following words:

Unless the prior Official Zoning Map has been lost, or has been totally destroyed, the prior map or any significant parts thereof remaining shall be preserved, together with all available records pertaining to its adoption or amendment.