mola_input_rosbag1

Distro	Build dev	Builds	Stable release
ROS 2 Humble (u22.04)		amd64 arm64
ROS 2 Jazzy (u24.04)
ROS 2 Kilted (u24.04)
ROS 2 Lyrical (u26.04)		amd64 arm64
ROS 2 Rolling (u26.04)		amd64 arm64

A MOLA RawDataSource module that reads ROS 1 .bag files and exposes their contents as MOLA observations, without requiring a ROS 1 installation.

The ROS 1 bag (de)serialization, message definitions, and rosbag_storage reader are vendored inside this package (see the ros1/ and mrpt_ros_bridge/ subdirectories), so the module builds and runs in a pure ROS 2 (or even non-ROS) colcon workspace.

Typical uses:

• Feed a legacy ROS 1 dataset into MOLA LiDAR Odometry or any other MOLA consumer.
• Turn MOLA into a ROS 1 -> ROS 2 bridge: read a .bag and re-publish its streams as ROS 2 topics + /tf, in real time (see demo below).
• Inspect raw sensor streams in the MOLA visualizer.

Supported message types

Topics with no known mapping are ignored (a one-time warning is logged).

Sensor poses and /tf

The pose of each sensor in the robot body frame is looked up from the bag’s /tf and /tf_static tree, as the transform base_link_frame_id -> <message frame_id>.

• Set base_link_frame_id to the name of your robot body frame. Note that many ROS 1 bags use namespaced frames (e.g. r1/base_link instead of base_link).
• If the relevant transform is not yet available when a message is read (e.g. the first few messages before any /tf), that single observation is dropped and a throttled warning lists the currently known tf frames, which is handy for discovering the correct base_link_frame_id.
• If your bag has no /tf, override the pose per sensor with fixed_sensor_pose (see the example in rosbag1_lidar.yaml).

Parameters

See mola-cli-launchs/rosbag1_lidar.yaml for a fully documented sensors example, and mola-cli-launchs/rosbag1_botanicgarden.yaml for an example combining multiple input bags with ground_truth_topic.

Demos

Two ready-to-use mola-cli launch files are provided under mola-cli-launchs/.

1. Visualize raw LiDAR streams

ROSBAG1_FILE=/path/to/dataset.bag \
  mola-cli src/mola_input_rosbag1/mola-cli-launchs/rosbag1_lidar.yaml

2. ROS 1 -> ROS 2 bridge

Example for the NTU Viral dataset:

ROSBAG1_FILE=/mnt/storage/ntu-viral/eee_01/eee_01.bag \
mola-cli \
  src/mola_input_rosbag1/mola-cli-launchs/rosbag1_ntu_viral.yaml \
  src/mola_input_rosbag1/mola-cli-launchs/publish_to_ros2.yam

Then, in another terminal with ROS 2 sourced:

```bash ros2 topic list

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