The district boundary lines of the Zone Map enclose an area of a designated district, and generally follow the center lines of streets or alleys, lot lines, or their extension, provided, however:
(a)   Where a boundary line is shown by dimension or relationship as being located a specific distance from and parallel to a street line, this distance shall control, or
(b)   Where a boundary line is shown as adjoining a railroad, it shall, unless otherwise fixed, be construed to coincide with the nearest boundary line of the railroad right of way, or
(c)   Where a boundary line is shown along a shore line, it shall be construed to coincide with the pierhead line, except that where no pierhead line has been established, the shore line shall control. Any fill, accretion, or island outside of a shore or pierhead line shall, unless otherwise designated, be construed to be in the same zone as the nearest adjoining district, however,
(d)   Where a boundary line does not coincide with any of the aforesaid lines, and where it is not located by dimensions shown on the Map, it shall be determined by use of the scale appearing thereon. In cases of uncertainty, the Board of Zoning Appeals shall determine the exact location.
      (1980 Code 150.13)