Recently the accuracy of the geodetic measurements and determination geometrical objects – coordinates and area is significantly impruved. The errors in calculating the area based on field measurements is less than the distorsion of the area as a result of designing it on the plane in Gauss, and is less than bringing field data to sea level. This paper gives the method of taking into account the height of each plot in calculating the area. The data processing is carried out in a single coordinate system in this method.