3D roof model generation and analysis supporting solar system positioning

Given the growing needs of renewable energy in urban areas, identifying suitable installation locations for solar systems is increasingly important. Existing energetic cadastres have often a limited level of detail in the analysed geometry, which needs to be rapidly updated following any changes in the buildings. The required 3D data can be generated by photogrammetry techniques and Structure-from-Motion (SfM) software. In this paper, the method was tested employing Digital Mapping Camera images (virtual images), on a case study in north-west of Italy. The results were analysed for assessing the reliability of the DSM produced by SfM methods, to be employed in solar radiation analyses. The problem of this kind of automatic 3D modelling could be sometimes the excessive detail in reconstructing the geometry of the roofs or the possible noise. The results are managed and analysed in Geographical Information System (GIS) tools. For the whole workflow, proprietary and free open source software (OSS) were used. The problems and limitations were investigated in order to evaluate and confirm the reliability and cost effectiveness of the described methods.