保存.pbstream地图-.pbstream地图转pgm，yaml文件
在线或离线生成pbstream文件，
roslaunch cartographer_ros my_demo_backpack_3d.launch bag_filename:=${HOME}/Downloads/***.bag
打开一个新终端，停止接收数据：
rosservice call /finish_trajectory 0
生成pbstream文件：
rosservice call /write_state "filename: '/home/hyper/Downloads/***.pbstream'
include_unfinished_submaps: false"
然后将pbstream文件转pgm，yaml文件：
roslaunch cartographer_ros assets_writer_ros_map.launch bag_filenames:=${HOME}/Downloads/***.bag pose_graph_filename:=${HOME}/Downloads/***.pbstrea
或使用命令：
rosrun cartographer_ros cartographer_pbstream_to_ros_map -map_filestem=/home/hyper/Downloads/savemap -pbstream_filename=/home/hyper/Downloads/***.pbstream -resolution=0.05