The methods of calculating areas of the large territories, the boundaries of which are determined by the coordinates of polygon vertexes are considered. The dependence of the calculating areas mistakes caused by the distances between polygon vertexes is shown. Also we made a conclusion that is necessary to calculate coordinates of the intermediate points, laying on the geodetic line in cases when the distances between the proximate polygon vertexes are above permissible value.
Keywords: areas calculating, accuracy estimation, mistake, coordinates, geodesy.