Three-dimensional survey techniques and hydrogeological risk: network sharing of high resolution LiDAR data Case study in the Veneto region.

3D surveying techniques dealing with high density measurement (i.e. through airborne LiDAR by TLS - Terrestrial Laser Scanner - or by mobile mapping) allow to survey and observe the territory with accuracy, a particular resolution and richness of details extremely high compared to traditional survey approaches. These technologies, due to the size of raw data, not allow the sharing and the direct reading of 3D data by different users. Usually, the data are put into standard formats (digital terrain model, contour lines, etc.) to be shared. The raw data (with all the associated contents) are, on the other hand, generally lost or saved in formats and devices (hard disks or DVD) that doesn't make it available to the costumer. An application of a technology developed by the University of Brescia (together with the spin-off Gexcel srl) is presented. This application allows the sharing and visualization of these data by web. The difficulty of implementing the sharing technologies of LiDAR data lies in the transfer of 3D surveyed data, even if only to display them. This research intends to propose a new way of data managing/transmission, also by internet, enabling to store 3D LiDAR data in a single file and to add different layers on this model. In particular, the research shows how in a file - on a remote server - it is possible to store 3D multi-resolution data about landslides of the Veneto Region. These 3D data (enriched by different layers) can be visualized, downloaded, queried and shared via web. It also shows how it can be displayed on 3D model, information levels from GIS that analyze data of hydrological risk. The research proposes a first application of LiDAR data web sharing applied to studies of hydrological disasters of the Veneto Region. This is intended as an example of a useful technology to support all the activities for rapid decisions.