Research And Implementation Of Three-dimensional Electronic Sand Table System

With the development of digital image technology,the 3D image display technology came up,and the geographic information has been developed particularly from the two-dimensional to 3D geographic image.This paper based on the analysis of the 3D surface modeling technology,mainly analyses and discuss the branch?corresponding and overlap ratio of the contour lines,which appear during the process of the Contour connection algorithm,in order to find out the way of surface modeling algorithm?According to the idea of the marching cubes(Marhcing Cube,MC)surface modeling algorithm,I proposes a new algorithm for contour based object surface reconstruction--mobile pyranid algorithm(MP algorithm).In this research,I made a modification for the problem of the branch and corresponding of the contour line occurred in the past MC algorithm,which can solve the problem of the Splicing of contour line.Besides,when the contact ratio and overlap ratio of the equivalent contour and the original contour is low,the MC algorithm needs interpolation,which will result in a great amount of waste in computer resource.So,the MP algorithm can meet different application purposes as well as the rendering quality and rendering speed,by constructing pyramid model of outsourcing,calculation contour projection area.The feasibility and availability of the algorithm is tested by a lot of experiments.According to the requirements of software engineering,I designed and developed an electronic sand table system based on the system of C/S mode,the system is divided into five function modules which are data input module,3D scene display module,spatial analysis module,roaming interactive control module and data output module.Among which,the 3D surface modeling is made by using the MP algorithm,and then I made an improved display' list and the double buffer technology to improve the properties of 3D display of electronic sand table.Finally,the electronic sand table system was in the Windows software platform,by using the Visual C++ and OpenGL,and its overall properties reach the target of the system design,to effectively achieve the needs of the users.