When uncertainty exists with respect to the boundaries of the various districts as shown on the zoning map, the following rules shall apply:
A. District boundary lines are either the centerlines of railroads, highways, streets, alleys or easements, or the boundary lines of sections, quarter sections, divisions of sections, tracts or lots, or such lines extended unless otherwise indicated.
B. In areas not subdivided into lots and blocks, wherever a district is indicated as a strip adjacent to and paralleling a street or highway, the depth of such strips shall be in accordance with the dimension shown on the map measured at right angles from the centerline of the street or highway, and the length of frontage shall be in accordance with dimensions shown on the sections, quarter sections, divisions of sections, tracts or lots, or such lines extended unless otherwise indicated.
C. Where a lot held in one ownership and of record on the effective date hereof is divided by a district boundary line, the entire lot shall be construed to be within the less restricted district; provided, that the construction shall not apply if it increases the less restricted frontage of the lot by more than twenty five feet (25'). (Ord. 381-87, 6-9-1987)