tf2_ros Documentation

tf2_ros is the C++ ROS wrapper around the tf2 transform library.

Code API

To broadcast transforms using ROS:

• Call ros::init() to initialize a node.
• Construct a tf2_ros::TransformBroadcaster.
• Pass a geometry_msgs::TransformStamped message to tf2_ros::TransformBroadcaster::sendTransform().
  • Alternatively, pass a vector of geometry_msgs::TransformStamped messages.
• Use tf2_ros::StaticTransformBroadcaster for "latching" behavior when transforms that are not expected to change.

To listen for transforms using ROS:

• Construct an instance of a class that implements tf2_ros::BufferInterface.
  • tf2_ros::Buffer is the standard implementation which offers a tf2_frames service that can respond to requests with a tf2_msgs::FrameGraph.
  • tf2_ros::BufferClient uses an actionlib::SimpleActionClient to wait for the requested transform to become available.
    • It should be used with a tf2_ros::BufferServer, which offers the corresponding actionlib::ActionSErver.
• Pass the tf2_ros::Buffer to the constructor of tf2_ros::TransformListener.
  • Optionally, pass a ros::NodeHandle (otherwise TransformListener will connect to the node for the process).
  • Optionally, specify if the TransformListener runs in its own thread or not.
• Use tf2_ros::BufferInterface::transform() to apply a transform on the tf server to an input frame.
  • Or, check if a transform is available with tf2_ros::BufferInterface::canTransform().
  • Then, call tf2_ros::BufferInterface::lookupTransform() to get the transform between two frames.
• Construct a tf2_ros::MessageFilter with the TransformListener to apply a transformation to incoming frames.
  • This is especially useful when streaming sensor data.

List of exceptions thrown in this library:

• tf2::LookupException
• tf2::ConnectivityException
• tf2::ExtrapolationException
• tf2::InvalidArgumentException
• tf2::TimeoutException
• tf2::TransformException

For more information, see the tf2 tutorials: http://wiki.ros.org/tf2/Tutorials

Or, get an overview of data type conversion methods in geometry_experimental packages.