The boundaries of these districts are indicated upon the OFFICIAL ZONING MAP of the City, which map is made a part of these regulations by reference. The said OFFICIAL ZONING MAP and all notations, references, and other matters shown thereon shall be as if the notations, references and other matters set forth by said map were all fully described herein. The OFFICIAL ZONING MAP shall be filed in the office of the Clerk. The OFFICIAL ZONING MAP shall be identified by the signature of the Mayor, attested by the Clerk under the following words:

The district boundaries are either lot lines or the centerlines of streets and alleys, unless otherwise shown. Where the districts designated are bounded approximately by street, alley, or lot lines and are not dimensioned otherwise, the lot lines or the centerlines of streets and alleys shall be considered to be the boundary of the district.