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With the continuous improvement of user needs and the continuous enrichment of spatial data, the same geospatial scope includes different types of spatial data such as terrain, remote sensing images, and 3D models of oblique photogrammetry. 3D WebGIS cannot effectively load different types of spatial da⁃ ta in the same scene . This paper proposes a spatial data loading optimization method for 3D WebGIS to op⁃ timize the efficient loading of multiple types of spatial data. First, using the structural features of 3D Tiles with regular enclosing volume shapes and overlapping regions, a fast growth algorithm based on binary tree is proposed to locate and extract the outer boundary of 3D model. Then, there were jagged protrusions on the outer boundary of the roughly extracted polygon. In order to solve the problem, a polygon simplification method based on two neighboring points was proposed to optimize the outer boundary of the polygon to achieve accurate extraction of the outer boundary of the 3D model. Finally, by judging the inclusion of map tile and terrain tile data relationship to achieve selective loading of tile data. Experiments show that when the viewpoint height is below 300 meters, the total load of map tile data can be reduced by about 40%, indi⁃ cating that the optimization method in this paper can significantly improve the data loading efficiency of the system without affecting the visualization of 3D WebGIS . [ABSTRACT FROM AUTHOR]

The modeling of complex mine roadways， such as curved roadways， intersection roadways， and variable cross-section roadways， is the key and difficult point when building the 3D models of roadway network. Deficiencies exists in the existing method when reconstructing complex roadway networks based on traverse data， especially for the curved intersection roadways which are common in mines. This paper proposed a basic component assembly method (BCAM) for the modeling of the 3D roadway network by using the underground survey data of coal mine roadway. By applying three steps of BCAM， namely the modeling of roadway centerlines， the modeling of roadway sidelines， and the modeling of the basic component of roadway (BCR)， 3D models of complex roadway network can be automatically constructed. The experimental results show that the proposed method is robust， and the modeling time increases linearly and steadily with the increase of data volume. The established 3D model of the roadway network can support various analyses on space， geometry， and mechanics for smart mines. [ABSTRACT FROM AUTHOR]

The existing coal seam modeling methods using discrete points or geological boundaries from multi-source data lack enough attention to the dynamic changes of coal seam in the mining process. A new 3D coal seam fine modeling method is proposed. Firstly， creating regional grid of the mining area and converted to triangulated irregular network (TIN)，inter polating attributes of TIN nodes (elevation and thickness)using ordinary Kriging method，and then a generalized tri-prism(GTP) model of coal seam will be built as the initial model. Secondly， the initial model is refined gradually by the dynamic data within the influence domain of these data. A prototype system is created and implemented in Qianjiaying coal mine， Tangshan， China. The result shows that this method can accurately reflect the change of 3D coal seam model from the dynamic data， thus the accuracy of the 3D coal seam model can be improved gradually. [ABSTRACT FROM AUTHOR]