The Developing Of Query&Analysis System Of3D Digital City

Now we enter the era of information explosion. With the development of science and technology, we can obtain data through multiple accesses. The cost to get data like remote sensing data, DEM elevation data and vector data is getting cheaper. More important is that the improvement of the resolution and update rate of the data. Data acquisition is the prerequisite of the development of digital earth and digital city.With the maturation of2D GIS technology and the development of3D GIS,3D digital city is more than a browsing system, but can offer spatial analysis. The analysis function of3D digital city can provide scientific and reliable strategy to urban planning, transportation planning, public facilities and greening. In addition,3D digital city can be applied to emergency warming and other aspect of the city.In this paper, we researched3D visualization technology and3D GIS analysis function and provide the key technology to establish3D digital city. Firstly, we offer the detailed design frame of3D digital city, and then complete the system.3D digital city system combined with digital earth, digital city and3D visualization is created, containing query and analysis, shortest path analysis, visual analysis, flood analysis, path roaming, measurement analysis which can be found in common3D GIS. The development of system which comes from base will promote the domestic development of3D digital city. In this paper, the specific research contents were as the following:The first chapter introduced the background of the research, and put forward the research purpose and significance, and the research status at home and abroad was summarized.The second chapter introduced data classification and data sources in the query-analysis system of3D digital cityThe third chapter introduced theory and algorithms needed in thedigital3D city modeling, namely the LOD and quadtree, shortest path analysis modeling, measurement modeling, visibility analysis modeling and flooding analysis modeling.The fourth chapter made a detailed introduction to the overall design of the system through the system design objectives and principles,requirements analysis, overall framework, system function design, etc.The fifth chapter made a detailed introduction tothe implementation of the system from the3D scene creation,3D scene browsing and roaming,3D scene editor and3D scene analysis, etc.The last chapter summarized the whole paper, and pointed out the defects of the paper with the planning of latter work.