A land survey is a professional drawing that identifies property boundaries and provides the location of any structures located on the property. Land surveys are extremely important and a necessity for any land owner or prospective land owner. The land survey drawing will depict the four corners of the property and will be marked on the property by a licensed land surveyor. You will use the drawing document and physical markers on the property to establish your property lines or building site. When do you need a Land Survey? There are many reasons why you would need a land survey.