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.

   1.   If, in accordance with the provisions of this chapter and Chapter 414, 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:

   2.   “By official action of the City Council, the following changes were made in the Official Zoning Map.” (Indicating the changes by ordinance numbers and date of publication.)

   3.   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. (See Editor’s Note at the end of this zoning ordinance.)

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:

“This is to certify that this Official Zoning Map supersedes and replaces the Official Zoning Map per Ordinance No. ________ of the City of Mount Vernon, Iowa.”

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.

Where uncertainty exists as to the boundaries of districts as shown on the Official Zoning Map, the following rules shall apply:

1.   Boundaries indicated as approximately following the centerlines of streets, highways, or alleys shall be construed to follow such centerlines;

2.   Boundaries indicated as approximately following platted lot lines shall be construed as following such lot lines;

3.   Boundaries indicated as approximately following City limits shall be construed as following such City limits;

4.   Boundaries indicated as following railroad lines shall be construed to be midway between the main tracks;

5.   Boundaries indicated as following shorelines shall be construed to follow such shorelines, and in the event of change in the shoreline shall be construed as moving with the actual shoreline; boundaries indicated as approximately following the center lines of streams, rivers, or other bodies of water shall be construed to follow such center lines;

6.   Boundaries indicated as parallel to or extensions of features indicated in Subsections 1 through 3 above shall be so construed. Distances not specifically indicated on the Official Zoning Map shall be determined by the scale of the map;

7.   Where physical or cultural features existing on the ground are at variance with those shown on the Official Zoning Map, or in other circumstances not covered by Subsections 1 through 6 above, the Board of Adjustment shall interpret the district boundaries;

8.   Whenever Council vacates and disposes of a street or alley, adjacent districts shall extend to the centerline of the vacation;

9.   Whenever a variance exists between the Zoning Map and the legal description on an amendment to this chapter, the legal description applies.