Surveying is the technique and science of accurately finding out the position of points and the distances and angles between them. These points are usually, but not always, associated with positions on the surface of the Earth. They are often used to make land maps and boundaries for ownership of land. A person who does the surveying is called a surveyor. In order to find the information they need, surveyors use geometry, engineering, trigonometry, mathematics, physics, and law.