For the purposes of this ordinance, the city is hereby divided into the types of districts designated as follows:

The boundaries of the above districts are hereby established as shown on the official zoning map.

3.2.1.

Boundary interpretations. 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 mid-way between the main tracks.

5.

Boundaries indicated as following shore lines shall be construed to follow such shore lines, and in the event of change in the shore line it shall be construed as moving with the actual shore line; boundaries indicated as approximately following the center lines of streams, rivers, canals, lakes, 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 paragraphs 1 through 5 above shall be so construed. Distances not specifically indicated on the official zoning map shall be determined by the scale of the map.

7.

When physical or cultural features existing on the ground are at variance with those shown on the official zoning map or in circumstances not covered by paragraphs 1 through 6 above, the board of zoning adjustment, hereinafter referred to as "the board", shall interpret the district boundaries.

8.

Where a district boundary line divides a lot, which was in single ownership at the time of passage of this ordinance, the board may permit, as a special exception, the extension of the regulations for either portion of the lot not to exceed 50 feet beyond the district line into the remaining portion of the lot.