In our thesis, we developed a prototype of an interactive 3D terrain visualization of Slovenia. We merged LiDAR data in form of height maps with orthophoto images, which were downloaded from the Slovenian Environment Agency's servers. We developed the prototype in Unity3D with programming language C\#.
For successful interactive visualization, we implemented multiple support systems. We divided the terrain into tiles. Each tile consists of metadata and terrain. The terrain was generated from height maps and ortophoto images. For correct alignment, we implemented an offset alignment system and control point system.
Because of a high number of tiles, we implemented a level of detail system. The closer the camera is to the terrain, the higher resolution tiles are loaded and shown. The system also helped us with better memory management, as there are fewer tiles loaded in the memory. Tiles are linked together into a hierarchy, which is managed by a data structure called TreeStructure, which is grouping tiles into 3$\times$3 grid.
Images were loaded and processed asynchronously, via coroutines, which helped us maintain a responsive user interface.
For additional performance gains, all images were converted to a proprietary format, which enabled us to use faster Unity functions.