Research on construction of “one map” data equalization non-uniform vector tile in coal mine

Traditional map tiles are widely used for spatial data transmission in coal mine “one map”. However, there have been some problems,such as difficulties in customizing display, unbalanced data loading, and excessive time. Combined with the characteristics of coal mine “one map” spatial data, the vector map tile is divided and analyzed. Based on the rendering process, it is found that the data imbalance is low and the tile loading efficiency is low. In order to solve this problem, a non-uniform vector tile construction method based on data equalization is proposed in this paper. Specifically, the division of tiles is implemented in two steps: initial division and subdivision. When the initial partition is used, the tile is no longer generated for the region whose data amount is smaller than the threshold, and the existing zoom scale maximum tile in the region is directly called when the map is rendered;In terms of the subdivision step, the tile with the largest amount of the set obtained by the initial division is equally divided, so the amount of tiles can be more balanced. In this way, it is ensured that the tile level of the areas of dense features is finer and the tile level of the areas of sparse features is rougher. Furthermore, using the original vector data size with 356 MB and 137 layers, the loading efficiency of uniform vector tile, simplified uniform vector tile and non-uniform tile based on data balance are compared with each other. Experiments have shown that the method proposed in this paper can increase the loading speed by more than two times compared with the method of simplified uniform vector tiles, which can greatly optimize the user experience.