This paper describes a computer method for drawing, on an incremental plotter, a set of contours when the height is available only for some arbitrary collection of points. The method is based on a distance-weighted, least-squares approximation technique, with the weights varying with the distance of the data points. It is suitable not only for mathematically derived data, but also for data of geographical and other non-mathematical origins, for which numerical approximations are not usually appropriate. The paper includes a comparison with other approximation techniques.