1. A computer-implemented method for extracting level and reference grid information from point cloud data, comprising: obtaining point cloud data comprising laser scanning points; organizing the point cloud data into a three-dimensional structure of voxels, the three-dimensional structure consisting of an X-axis, Y-axis, and Z-axis; extracting level information; and extracting reference grid information from an X-axis histogram of the voxels positioned along the X-axis of the three-dimensional voxel structure and a Y-axis histogram of the voxels positioned along the Y-axis of the three-dimensional voxel structure.