When uncertainty exists with respect to the boundaries of the various districts, as shown on the Itasca Zoning Map, the following rules shall apply:

   1.   District boundary lines are either the center lines of railroads, highways, streets, alleys, easements, or tract or lot lines, or such lines extended unless otherwise indicated.

   2.   In areas not subdivided into lots and blocks, wherever a district is indicated as a strip adjacent to a paralleling a street, highway or railroad, the depth of such strips shall be in accordance with the dimensions shown on the maps measured at right angles from the centerline of a street, highway or railroad, and the length of frontage shall be in accordance with dimensions shown on the map form center lines of streets, highways or railroad rights-of-way, unless otherwise indicated.

   3.   Where a lot is held in one (1) ownership and of record on the effective date of the Ordinance is divided by a district boundary line, the entire lot may be constructed to be within the less restricted district. If it increases the less restricted frontage of the lot by less than twenty-five (25) feet, it shall be constructed in the more restrictive zoning district.