mkdir -p ~/ros2_ws/src && cd ~/ros2_ws/src
git clone https://github.com/RyuYamamoto/ndt_slam.git
cd ~/ros2_ws && colcon build --symlink-install --cmake-args -DCMAKE_BUILD_TYPE=Release
launch ndt_slam.
ros2 launch ndt_slam ndt_slam.launch.xml
play rosbag file.
ros2 bag play <ROSBAG PATH> --clock 100
save pcd map.
ros2 service call /save_map std_srvs/srv/Empty
# PCD Map are saved in /tmp/map.pcd