53 Pa. Stat. § 13805
Every ordinance, which shall authorize the acquisition of additional land and property in connection with any improvement, shall provide that the department of public works shall make a plain and accurate map, showing the land and property to be acquired for the improvement, and such additional land and property to be acquired in connection with the land and property to be acquired for the improvement. When additional land and property is to be taken by condemnation, the petition for the appointment of viewers shall separately describe such additional land and property to be so taken, and shall state what part of the land and property to be condemned is required for the improvement and what part thereof is to be acquired as additional land and property. The acquisition of such additional land and property, when duly authorized, shall be deemed to be for a public purpose.
53 P.S. § 13805