A method for assessing a ground area for suitability as a landing zone or taxi area for aircraft is provided. Three-dimensional data for the ground area in a plurality of measurement cycles in a 3D sensor is produced. The measured-value density of the three-dimensional data and also of at least one further statistical property of the three-dimensional data is determined. A measure of the local roughness of the ground area is produced based on the measured-value density and the at least one further statistical property. The individual area elements of the ground area are classified on the basis of the roughness values produced according to the degree of suitability of said area elements as a landing area or taxi area.