Where uncertainty exists with respect to the boundaries of the various districts, as shown on any zoning map, the following rules apply:
(a) The district boundaries are street lines unless otherwise shown; and where the designation on the zoning map indicates a boundary that approximately coincides with an existing street line, that street line shall be construed to be the boundary;
(b) Where a designation on the zoning map indicates a district boundary that approximately coincides with existing lot lines, those lot lines shall be construed to be the boundary;
(c) In undivided property, the district boundary lines on the zoning map shall be determined by measurement according to the scale of the maps;
(d) No district boundary shown on the zoning map shall be construed as extending the authority of L&I beyond the low water mark on any navigable stream; and
(e) Where a street is stricken from the City Plan or where a railroad right-of-way is abandoned, the zoning boundaries of the abutting land shall be extended to the centerline of the vacated street or right-of-way, unless otherwise provided by the City Council.