For the purpose of applying the provisions of this chapter, the Borough of Mars, County of Butler, Commonwealth of Pennsylvania, is hereby divided into the following zoning districts:

The boundaries of these districts are hereby established as shown on the map, entitled "Official Zoning Map," on file in the office of the Zoning Officer, which map, with all explanatory matter thereon, shall be deemed to accompany, be, and is hereby made a part of this chapter. The Official Zoning Ordinance Map shall carry the signature of the Mayor, President of the Borough Council, Chairman of the Planning Commission and the Borough Secretary, certifying that it is the true map adopted by the Council of the Borough of Mars. All amendments shall be identified on the map and similarly certified.

The boundaries between districts are, unless otherwise indicated, either the center line of a street or highway right-of-way or such lines extended, or parallel lines thereto, property lines or other physical boundaries and delineations. Where streets, property lines or other physical boundaries and delineations are not applicable, boundaries shall be determined by the scale shown on the Official Zoning Ordinance Map, as certified.

When a district boundary line divides a lot held in single and separate ownership at the effective date of this chapter, the regulations as to the use in the less restricted district shall extend over the portion of the lot in the more restricted district a distance of not more than 50 feet beyond the district boundary line.