Integration Of Voxel Models With GeoSOT-3D Grids Based On Coordinate Matching

The digital twins city is a new stage of development for smart city.Building "digital twins city" and realizing digital governance of cities are important propositions of the times for city builders and managers.The voxel model has gained a lot of attention for its advantages of prensting the interior of entities and efficient indexing stratery,but it is often inadequately associated with real geographic locations.The global location grid is a geo-fitted network based on the(ellipsoidal)sphere to dissect the earth,which supports the management,calculation and expression of spatio-temporal information on a global scale in a discrete global grid.Its advantages are easy spatial calculation,fast positioning query,and convenient information integration and multi-dimensional expression.For the requirements of real 3D model construction and global data management in digital twins city,and the problem that the local coordinates of voxel model are not associated with geographic location,this paper takes Geo SOT-3D framework as an example,researches the integration method of voxel model and global location grid,and develops a prototype system to integrate and manage the voxel model with the global location grid.Our study will provide an alternative solution for building models in digital twins city.In this paper,we first propose a method for positioning the voxel model in the global location grid.Specifically,we define the positioning parameters of the voxel model,propose the rules for selecting the global location grid levels based on the volume of the voxel model,and then design the calculation method for the exact location of anchor point of the voxel model in the global location grid.Based on this method,the anchor point of the voxel model can be positioned to specific location in the global position grid,and the association of the voxel model with the global spatial positioning framework can be established.On this basis,the integrated model of voxel model and global location grid is established from two levels,the single voxel and voxel model as a whole.The integrated model realizes the accurate mapping of voxel model and global location grid.Based on the aforementioned method,a prototype system based on Cesium platform is built to realize the data storage management,query retrieval and true 3D visualization of the voxel model and single voxel based on the global location grid.The system uses My SQL database to store the data,Java and Java Script to build the voxel model based on the point cloud data.The system verifies the feasibility of locating and integrating the voxel model in the global location grid.