First, we will create a ros package in our workspace or copy the chapter3_tutorials/tf_tutorials file from GitHub:

$ catkin_create_pkg tf_tutorials tf roscpp rospy turtlesim 

Next, we will create the tf_tutorials/src/turtle_tf_broadcaster.cpp file and add the source code:

#include <ros/ros.h> 
#include <tf/transform_broadcaster.h> 
#include <turtlesim/Pose.h> 
 
std::string turtle_name; 
 
 
void poseCallback(const turtlesim::PoseConstPtr& msg){ 
  static tf::TransformBroadcaster br; 
  tf::Transform transform; 
  transform.setOrigin( tf::Vector3(msg->x, msg->y, 0.0) ); 
  tf::Quaternion q; 
  q.setRPY(0, 0, msg->theta); 
  transform.setRotation(q); 
  br.sendTransform(tf::StampedTransform(transform, ros::Time::now(), "world", turtle_name)); 
} 
 
int main(int argc, char** argv){ 
  ros::init(argc, argv, "tf_broadcaster"); 
  if (argc != 2){ROS_ERROR("need turtle name as argument"); return -1;}; 
  turtle_name = argv[1]; 
 
  ros::NodeHandle node; 
  ros::Subscriber sub = node.subscribe(turtle_name+"/pose", 10, &poseCallback); 
 
  ros::spin(); 
  return 0; 
}; 

Here, we will create a TransformBroadcaster object that will be used to send the transformations over the ROS communication network. And, we will also create a Transform object and copy the information from the 2D turtle pose into the 3D transformation:

br.sendTransform(tf::StampedTransform(transform, ros::Time::now(), "world", turtle_name)); 

In the preceding code snippet, the real work is done where Transform with TransformBroadcaster requires four arguments:

• First, we will pass in transform itself, which was created in the preceding code snippet.
• Next, we provide a timestamp to the transform being published. We'll just stamp it with the current time, ros::Time::now().
• Then, we will provide the name of the parent frame of the link we have created, in this case, "world".
• Finally, we will provide the name of the child frame of the link we have created, in this case, the name of the turtle itself.