The Expression Of Two And Three-dimensional Geospatial Information Integration

The nature of the GIS system is to achieve perfect simulation and accurate analysis of the real nature environment,however,the existing GIS systems can't achieve this goal due to the limitations of people's cognitive level and computer technology.Two three-dimensional linkage expression of the geographic information and posture is the development direction of GIS applications,and it's also a hot topic of the geographic information industry.With the development of new technologies and the enhancement of demand,intense researches with multi-knowledge and multiple-design patterns are launched for applications about the GIS two and three dimensional linkage at home and abroad,and certain achievement has been obtained,but has not yet formed a complete standard.In this paper,focusing on two three-dimensional GIS system linked manner,using data-driven method,we make research and practice for two and three dimensional linkage expression of the Geographic Information and posture.The main contents include:1.The current research status and development trends of 3D GIS were analyzed and the existing problems of 3D GIS was illustrated.Then the problems which should be solved in this thesis was determined after explaining the significance of two and three dimensional integration and analyzing related technologies.2.After analyzing the two and three dimensional modeling technologies,the model integrated with TIN and CSG was determined as the integration spatial data model structure.The features of terrain and surface were used for modeling and the TIN generation rate was improved due to the improvement of TIN triangle subdivision algorithm which have the constraint condition so that the basis of two and three dimensional linkage expression could be achieved.3.The organizational structure of two and three dimensional spatial data was analyzed and the algorithm of transforming the 2D geographic data to 3D spatial data was realized after analyzing the integration organization method of terrain and object in detail.A method of network partition was adopted to speed up the transforming rate from INT to Grid and a two and three dimensional integration spatial data structure which was focused on file system and relational database was proposed to do the relevant work of data organization and storage.These works could pave the way to realizing the two and three dimensional linkage expression.4.The main work was focused on the method of two and three dimensional linkage expression.The same interface which could realizing the render of two and three dimensional model was designed through OGRE 3D engine,then the detailed process of data driven was shown with the improvement and extension of data driven method according to the characteristic of GIS system and user requirement after analyzing the linkage principle and existing two and three dimensional linkage technologies and the linkage precision analysis was done with the proposed method which could improve the precision of integration linkage.5.The experimental system of two and three dimensional linkage expression based on data driven was developed which realizing the functions of integration control,integration roaming,searching and analysis so that the theory studied in this thesis could be verified.