/elevation_map topic exists but no messages are published

[HARIBALAKUMAR-P]

Issue: /elevation_map topic exists but no data is being published

Hi,

I am using this elevation mapping package for outdoor local mapping with a Velodyne 3D LiDAR in a Gazebo simulation for a simple AMR robot.

System Setup

• ROS2
• Gazebo simulation
• Velodyne 3D LiDAR
• Map frame: map
• Robot base frame: base_link
• Odometry topic: /odom

Parameter Configuration

/**:
  ros__parameters:
    inputs : ['ground_truth_cloud']

    ground_truth_cloud:
      type: pointcloud
      topic: /velodyne2/velodyne_points2
      queue_size: 10
      publish_on_update: true
      sensor_processor:
        type: laser

    map_frame_id: "map"
    robot_base_frame_id: "base_link"
    robot_pose_with_covariance_topic: "/odom"

    track_point_frame_id: "base_link"
    track_point_x: 0.0
    track_point_y: 0.0
    track_point_z: 0.0

Observed Behavior

When running:

ros2 topic list

Both topics exist:

/elevation_map
/elevation_map_raw_post

However:

ros2 topic echo /elevation_map

does not output any data, while:

ros2 topic echo /elevation_map_raw_post

does publish data.

Debug Checks Performed

• Verified that the LiDAR topic /velodyne2/velodyne_points2 is publishing pointcloud data.
• /odom topic is publishing correctly.
• TF tree exists between map and base_link.
• The elevation mapping node is running without errors.

Question

1. Under what conditions will /elevation_map start publishing data?
2. Is there any additional filter or processing step required to enable publishing to /elevation_map?
3. Could the sensor processor configuration affect this behavior?

Any suggestions on how to debug this issue would be greatly appreciated.

Thanks!