The boundaries between base zones are, unless otherwise indicated, either the central lines of streets, lanes, watercourses and rights-of-way of power lines, railroads and other public utilities, parcel lines, or such lines extended or lines parallel thereto. Where the boundaries of a single district are indicated as including directly opposite sides of a street, lane, lake or watercourse, or right-of-way of a power line or other public utility, for any portion of its length, the district shall be construed to include the entire bed or such street, lane, lake or watercourse or right-of-way of such power line, railroad or other public utility lying within such portion of its length. Where uncertainty exists as to the location of any said boundaries as shown on the Zoning Map, the following rules shall be used to identify the boundary:

Whenever federal or state-owned property is included in one or more zoning districts, it shall be subject to the provisions of this chapter to the extent permitted by the Constitution and laws of the United States of America and the Commonwealth of Pennsylvania.