title: ROS RVIZ: How to visualize a point cloud that doesn't have a fixed frame transform
body: <p>I was following the ROS official documentation on how to <a href="http://wiki.ros.org/pcl_ros" rel="noreferrer">publish a point cloud</a> and I was able to successfully run the code. Now I'm trying to visualize the point cloud using ROS RVIZ but I'm getting an error. </p>
  
  <blockquote>
    <p>Transform [sender=unknown_publisher]
    For frame [single_frame]: Fixed Frame [map] does not exist</p>
  </blockquote>
  
  <p><a href="https://i.stack.imgur.com/I4avL.png" rel="noreferrer"><img src="https://i.stack.imgur.com/I4avL.png" alt="enter image description here"></a> </p>
  
  <p>How can I overcome this error? It says the frame does not exist. Is there a workaround or a configuration setting in RVIZ to bypass the error? Or how can I update my c++ code to update the frame object? Can you please provide me with some example code? </p>