A method for determining shape deviations of a real actual surface on the basis of measured vertical information of measurement points of the actual surface section is provided. Measurement points are located in a measurement-point extent section, wherein the method uses evaluation sections, which are arranged at offsets to each other and, altogether, extend over the measurement-point extent section. The method includes (a) for each measurement point of a number of measurement points of each evaluation section of the first evaluation sections, determining a maximum vertical distance that results as the greatest distance in a specified vertical direction between two measurement points, and (b) determining an evaluation-section slope, which represents a straight connecting line between an evaluation-section lowest point and an evaluation-section highest point, wherein, in a further step, the value pairs of a maximum vertical distance and of an evaluation-section slope, which value pairs are determined in a plurality of iterations for the respective evaluation sections thereof, are associated with a limit criterion.