Research On Mass City Models Scheduling And Viewpoint Motion Prediction Algorithm Based On LOD

Location service capabilities,space restoration capabilities,data organization and analysis capabilities are the foundation of smart city core technologies,and the sleek display of the massive city model in spatial restoration capabilities is the key in a two and three-dimensional geographic information system.this paper solve the problem of unsmooth scheduling caused by slow scheduling in the three-dimensional display of massive city models.a model scheduling method based on quadtree index is proposed based on the model scheduling index mechanism;on the other hand,and improved Kalman filter algorithm for the point of sight trajectory prediction is presented based on viewpoint trajectory prediction.First this work come up with quadtree algorithm based on terrain patch,divided the 3D city models in,to patches and created regular index signs;Second the technique of view-based level-of-details(LOD)is used to cut 3D city models based on the change of viewpoint;Last the height deviation of planning grid is calculated as DH matrix roughness to eliminate the terrain cracks.This work use VS2010 platform and OpenSceneGraph(OSG)platform to realize the rapid visualization of massive data of 3D models,and the improved systerm load the 352G Cangzhou models to test the algorithm,the number of rendering models is from 412 to,3561,the result of scan rate is not less than 30 frames per second,compared with the current system is increased by 30%.This paper use the kalman filtering algorithm to predict the trajectory of a viewpoint,the algorithm based on the perspective of last frame and current frame location information and also obtain the location information of next frame under the perspective,the systerm load memory potential terrain blocks in advance.which will reduce the waiting time for terrain block scheduling.this work use the CangZhou city and XiJing hospital data to set contrast experiments to compare the effect of the kalman filtering algorithm with the effect of Lagrange prediction algorithm,the viewpoint prediction results show that compared with no treatment,the kalman filtering algorithm make frame rate increase by 20%,and the kalman filtering algorithm make frame rate increase 10%compared with the Lagrange algorithm,the result of contract experiments proves the kalman filtering algorithm increase 3D display frame rate effectively compared with the effect of the Lagrange prediction algorithm.