Research On Key Technologies Of 3D City Visualization Of Mobile Terminal

With the rapid development of 3D GIS,The importance attached to the strategic significance of digital cities from the state and the emergence of high-performance mobile devices,make the mobile three-dimensional city visualization technology has a broad development prospects and strong technical support.Based on the Android mobile platform,this paper studies the key technology of 3D city visualization.This paper focuses on the three-dimensional city model establishment,the three-dimensional data organization and plays the two-dimensional three-dimensional advantages to achieve two three-dimensional city scene linkage display,then achieves three-dimensional city Multi-resolution display the through simplification of the building model and the research on model selection strategy,finally designs and realizes the mobile three-dimensional city visual interactive system.Main work of this paper is as follows:The three-dimensional urban data model and organization are studied.Based on the research status and the advantages and disadvantages of the three-dimensional data model,and Combining ArcGIS and SketchUp,the three-dimensional building data model is established by using two-dimensional GIS data,and a way of data organization,which combines object-oriented thinking and boundary models,was put forward.The organization of the model data provides a convenient condition for the following study of the model simplification in this paper,also makes the software highly scalable and inherited,and is more in line with human habit.Research on the technology of two-and three-dimensional interaction in urban scene.This paper studies the rendering principle of OpenGL ES,re-divides the data by the texture material as a unit used for real-time rendering of 3D data.The organization of the model data can be improved,which can save real time drawing time and improve the fluency of interface interaction.At the same time,based on the actual demand of urban two-dimensional linkage display,three-dimensional scene visualization can be combined with positioning advantages of two-dimensional GIS in the city to achieve two three-dimensional linkage display.The essence of OpenGL ES scene transformation is studied,and the real-time linkage effect between two and three dimensions is realized based on this perspective.This kind of linkage can observe the city three-dimensional scene,at the same time the current perspective of the positioning and observation direction can also observed in the two-dimensional scene.It is very consistent with the characteristics of urban buildings,and has a wide range of applications.Research on multi-resolution display Technology of 3D city.The edge length and curvature are included into the folding cost of QEM algorithm.The simplification of the building model is achieved,the characteristics of the building are effectively maintained and its details are streamlined,and the quality of the stream has been greatly improved.At the same time,in order to avoid the redundant data brought by large-scale scheduling,the distance between the angle of view and the user experience is combined to reasonably plan the level of the model display.Finally the multi-resolution display effect of 3D city is realized.Design and development of 3D urban visualization software.Based on AABB bounding box,real-time collision detection technique through the axial division and comparison with dimensionality reduction is proposed to reduce the angle of view and improve the efficiency of real-time detection.This paper studies the principle of texture mapping,improves the real-time rendering efficiency through the optimization of texture map,and realizes the rendering of trees and sky scenes by texture mapping,which enriches the realism of 3D city scene.The overall architecture of the software system is designed to achieve a strong sense of strong,interactive three-dimensional city visualization system.