When automatically calculating 3D city models from remote sensing data (3D point clouds from laser scanning or photogrammetry), so-called step edges pose a particular challenge. These are edges where there are height jumps in roofs. Such edges are caused by roof houses, for example. Due to low resolution or noise in the data, our algorithms have so far only been able to align these edges inadequately. At OR 2018, we have now presented an optimization method with which as many roof edges as possible become vertical or parallel to edges of the building floor plan. The optimization problem is a so-called mixed-integer linear program. Dealing with such problems is a branch of operations research, the science at the interface between mathematics, computer science and business administration.
