The district boundaries on the Zoning Map are intended to follow property lines; center lines of roads, watercourses, or railroads; other identifiable physical features; or measured distances from property lines, center lines, or identifiable physical features. When the Zoning Officer cannot determine the location of a zoning district boundary by reference to the Zoning Map, the Zoning Officer shall refuse action and the Board shall interpret the location of the district boundary with reference to the scale of the Map, the Comprehensive Plan and the purposes set forth in all relevant provisions of this chapter.