Design And Implementation Of Large Terrain 3d Electronic Sand Table

Electronic sand table is also called digital sand table or virtual sand table. Electronic sand table is the combo of remote sensing (RS), geographic information systems (GIS), virtual reality (VR) and other technologies. With the computer technology's progress, electronic sand table is widely used in the military, real estate, space flight, education, entertainment, construction, urban planning and other industries. The main points of the production of electronic sand table are: firstly, cover the terrain grid with the texture to simulate the real topography; secondly, use the models of the buildings, roads, residential area and the terrain to generate a virtual three-dimensional scene; thirdly, actualize other special functions such as: terrain analysis, roaming, labeling and real situation of the natural environment's simulating is also needed.At the base of the summarize of predecessors'theory and practice, this article introduced the key technologies of electronic sand table and large area terrain simulation. Then made needs analysis of electronic sand table system and designed the overall framework and the functions of this system. Next, used ERDAS, Global Mapper and Photoshop CS to process the raw data of the terrain and texture, used the series of MultiGen-Paradigm software to generate three-dimensional scenes of electronic sand table. Finally, actualize all functions of this system under Microsoft Visual Studio development environment. This article also did a deeply research in the key technology such as: Virtual Texture, LADBM in CTS, Virtual Texture's mapping, Level of Detail (LOD), collision detecting on large area terrain, LADBM in VegaPrime and got a technique route about how to process the raw remote sensing data to the formate that CTS accept.