N.J. Stat. Ann. § 40:37-206

Before proceeding to purchase or condemn lands for a public park or place, the commission shall determine the location and quantity of land to be included in such park or place, and cause a survey thereof to be made together with a map showing the lands to be embraced therein. The map shall be kept by the commissioners in their office, and the boundary lines of every such park or place shall be recorded in a book to be kept by them for that purpose.