Generating 3D Roof Models from ALS Point Clouds Using Roof Line Topologies

The automation of 3D roof reconstruction has become a critical research topic in the field of GIScience. Existing roof plane-based methods for this purpose need to segment roof planes and further extract roof vertices and edges after topology analysis. However, the roof plane-based primitive extraction and topology analysis may lead to additional errors for the next step’s extraction result of roof vertices and edges. In this study, based on segmented roof plane point clouds, roof edges parallel to the x–y plane are extracted at first, and then the topology relationships of these special roof edges are analyzed and corrected by simple rules. This new approach simplifies the extraction of basic roof primitives and analyzes the roof structures and extracts roof vertices and edges at the same time, which reduce the accumulated errors by the processes of “multi-step primitive extraction—topology analysis—extraction of roof vertices and edges”. The qualitative and the preliminary quantitative experiment results indicate that the proposed approach can achieve the 3D roof reconstruction well.