mola_input_rosbag1

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

In the “Builds” column, the top badge is for amd64 and the bottom one for 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

CObservationOdometry is a planar type: it holds only (x, y, yaw) and a 2D twist (vx, vy, wz). For a 3D odometry source – a legged robot, a VIO, an aerial platform – that discards z, roll, pitch and the covariance the source publishes. To keep them, ask for the SE(3) type explicitly:

sensors:
  - topic: /state_estimator/odometry
    sensorLabel: odom
    type: CObservationRobotPose   # instead of the automatic CObservationOdometry

The automatic mapping is unchanged, so existing configurations keep the planar behavior. A source that publishes an all-zero covariance is given a default of 10 cm / 2 deg rather than being read as an exact measurement.

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

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