Modelling the world in 3D from VGI/Crowdsourced data

Within the last ten years, Volunteered Geographic Information (VGI) has developed rapidly and significantly influenced the world of GIScience. Most prominently, the OpenStreetMap (OSM) project maps our world in a detail never seen before in user-generated maps on the one hand. On the other hand, most of the urban area on our planet has been covered by hundreds of millions of photos uploaded on social media platforms, such as Flickr, Instagram, Mapillary, Weibo and others. These data are directly or indirectly geo-referenced and can be used to extract 3D information and model our world in the 3D environment. At the current stage, several approaches have been made available to visualise and generate the 3D world mainly using OpenStreetMap data. The 3D buildings are unfortunately restricted to a coarse level of detail, since no further information about facade structure is available on OSM. In this paper, the current work of reconstruction of 3D buildings by using the data both on OSM and Flickr is presented, whereby facade structure could be extracted from Flickr images and OSM footprints can be used to accelerate the process of dense image matching and to improve the accuracy of geo-referencing.