District boundaries shown on the lines of roads, streams, and transportation rights-of-way shall be deemed to follow the center lines. The vacation of roads shall not affect the location of such district boundaries. When the Zoning Officer cannot definitely determine the location of a district boundary by such center lines, by the scale or dimensions stated on the Zoning Map, or by the fact that it clearly coincides with a property line, he shall deny the application. The Zoning Hearing Board, upon appeal, shall interpret the location of the district boundary with reference to the scale of the Zoning Map and the purposes set forth in all relevant provisions of this chapter.