Research Of Key Technologies On Quick Visualization In3DGIS Large Data Scene

The quick visualization of large data scene is always a hot topic in the3DGIS field. However three-dimensional GIS relates to a large amount of topography, image and texture data, so it is very difficult to realize the real-time visualization of large number of data in the current hardware and software environment. In the research of GIS’s three-dimensional visualization, the idea of LOD has become an essential technique and method.In the past years, terrain simplification technology has been taking the CPU as the core, but its defect is that the extra time cost, resulting from acceleration, would even exceeds the time compensation of reducing the number of drawing grid. With the rapid development of GPU technology, people begin to look for a terrain visualization strategy that can take full advantage of GPU technology.On the basis of previous studies, this paper proposes a GPU-based LOD models to simplify the rendering strategy after the study of LOD model simplification technology and GPU technology. This article mainly completed the following several aspects of the work:1) Using multi-level quadtree to organize DEM data, which not only has the character of updating block terrain flexibly, but also has the feature of multi-resolution LOD terrain model’s multiple LOD factor control.2) For the LOD evaluation, the static node factors, node-to-screen distance, node size and the camera movement speed all shall be considered to construct the evaluation function of the LOD node.3) Combine technologies, such as OpenGL, GPU, GDAL and so on, Use C++language and realize the development of3D GIS quick visualization system, based on the Qt development platform.