One aspect relates to a method for reducing intermediate nodes in a polygonal chain having one or more intermediate nodes from a set of intermediate nodes between a starting node and an end node. In addition to the attributes of longitude and latitude, at least one further attribute having an attribute value and an attribute direction from a set of further attributes is assigned to the starting node, the end node and each intermediate node from the set of intermediate nodes. The attributes may be a gradient, a curve radius or a height. The following method steps are carried out in one or more processors for each intermediate node, starting with the starting node: comparing the attribute direction of the at least one further attribute of an intermediate node with the attribute direction of the at least one further attribute of the immediate predecessor node; marking the intermediate node as a significant node if the comparison reveals a change in the attribute direction; and applying a line generalization method with respect to the attributes of longitude and latitude, wherein the intermediate nodes marked as significant nodes must not be removed. The line generalization method may be, in particular, the 2D Douglas Peucker algorithm.