The practice of surveying land dates back to ancient history. Surveying is used for a number of interrelated purposes, such as to establish a precise location on the earth of a parcel of land along with its exact acreage, to ascertain boundaries for defining an area of ownership and tax liability, and to identify a property by a written legal description or to provide a review of the accuracy of an existing description. This data is of the utmost importance with regard to buying and selling land, and is also used to insure a clean, marketable title.