Research On Multi-resolution Modeling And Three-dimensional Multi-scale Real-time Rendering Method For Large Vector Data

With the development of3D GIS, more and more platforms have been developedtp build3D virtual scene, and the expression of spatial information is becoming moreintuitive.3D GIS is a hot reaseach field in the GIS study.However,3D-GIS development is confronted with various issuses and challenges.There is no mature spatial data model unified framework for visualization. As the lowintegration of traditional2D GIS data with meteorological, electromagnetic, marineenvironmental data, it can not form an intuitive and efficient global spatial informationvisualization perception means. There are still many technical difficulties in the vectordata3D real-time quick visualization. This paper focues on the digital earth platform formulti-source heterogeneous data, and then discusses vector data loading strategy andfast real-time visualization technology. The main work can be concluded as following;1. Based on thorough research of the organization and management of multi-sourceheterogeneous data and three-dimensional digital earth modeling technology, the digitalearth platform framework for heterogeneous data is designed,and to achieve somespherical interaction technology. This framework can meet the3D visualizationrequirements of large-scale GIS terrain data, and also laid the foundation for thesubsequent vector data, symbol data and environmental data integration.2. The vector data fast visualization process on Digital Earth is designed to solvelimited contradiction on large vector data and computer real-time processing, and thekey technologies need to be solved in the loading, rendering and caching.3．A multi-layer grid-quadtree hybrid index level divided mechanism is proposed togenerate multi-resolution vector data logic model. The multi-thread balanced loadingstrategy is used to accelerate the multi-scale block data loading process.It effectivelyimprove the vector data rendering speed with the minimum delay after completelymapping.4. Improvements are maded on texture fast rendering method based on the scenestructure after analysis and comparison of the vector data3D fast real-time renderingmethod. And then the simple vector data interaction techniques are designed.5. The design and implementation of large-scale spatial data visualization prototypeis discussed. The prototype implemented3D virtual environment rapid construction forheterogeneous data, validation framework and related technologies, and it can be usedas the basic platform for a variety of applications.