The district boundaries are street, alley and property lines unless otherwise shown, and where the districts designated on the map accompanying and made a part of this article are bounded approximately by street, alley, or property lines, the street, alley or property lines, shall be construed to be the boundary of the district.

Where the district boundaries are otherwise indicated, and where the property has been or may hereafter be divided into blocks and lots, the district boundaries shall be construed to be property lines, and where the districts designated on the map accompanying and made a part of the ordinance are bounded approximately by lot lines, the lot lines shall be construed to be the boundary of the districts unless the boundaries are otherwise indicated on the map.

In unsubdivided property, the district boundary lines on the map accompanying and made a part of this article shall be determined by use of the scale appearing on the map.

In case of a district boundary line dividing a platted lot into two parts, the district boundary line shall be construed to be the property line nearest the less restricted district.

Whenever any street, alley or other public way is vacated by official action of the city council, the zoning district adjoining each side of such street, alley or public way shall be automatically extended to the center of such vacation and all area included in the vacation shall then and henceforth be subject to all regulations of the extended districts.