s2 cell to proto (#338)
s2 cell to proto (#338)


cartographer-project/point_cloud_viewer,googlecartographer/point_cloud_viewer,googlecartographer/point_cloud_viewer,cartographer-project/point_cloud_viewer,cartographer-project/point_cloud_viewer,cartographer-project/point_cloud_viewer,googlecartographer/point_cloud_viewer,cartographer-project/point_cloud_viewer,googlecartographer/point_cloud_viewer,googlecartographer/point_cloud_viewer