The location of a structure on a parcel of land is depicted on a Certified Plot Plan, aerial imaging, United States Geological System (USGS) overlay mapping, and governed by the Zoning Act (M.G.L. Chapter 40A), and local zoning. Predominant land features such as roadways, stonewalls, and rivers may be present to approximate the relative location of a structure to the property boundaries of nearby wetland resource areas described in the Massachusetts Rivers Protection Act (Chapter 258) and Massachusetts Wetlands Protection Act (M.G.L. Chapter 131, Section 40). In many case plans showing the approximate location of the structure at local municipalities departments and archives. The age of the structure is important relative to the when local zoning bylaws became effective determining required structure setback to property boundaries. Determining whether a structure is in conformance to local Zoning By-Laws or Ordinances, wetland setbacks, and district use limitations is important for determining permitting processes for expansion or replacement of the existing structure. Location of a structure relational to a parcel of land is definitively determined through on-the-ground instrument survey by a licensed land surveyors registered in the Commonwealth of Massachusetts. The age of a structure can be found through the local municipal assessor. Permitting may vary depending on the location of a structure with jurisdictional regulatory authority included but not limited to local Building Department, Planning Board, Zoning Board of Appeals (ZBA) and Board of Selectmen. Understanding whether a structure is conforming, non-conforming, or pre-existing non-conforming determines the land value.