# roswtf says ERROR The following nodes should be connected but aren't [closed]

I'm having trouble using the transforms published via a rosbag file. I start roscore, then I run my node (called output_data) which simply subscribes to a PointStamped topic, and wants to transform this point to another frame and print it out. I then run rosbag play mybagfile.bag.

When the rosbag is running, I can see the tf tree is correctly formed with rosrun tf view_frames. I can also verify that the transform is working by doing "rosrun tf tf_echo destframe sourceframe".

However, my output_data node thinks that any frame I give it doesn't exist. More specifically, I'm calling transformPoint(target_frame, point_in, point_out), but "target_frame" never exists.

The real clue comes from running roswtf while this is happening. I get the following (hopefully) relevant info:

    WARNING The following node subscriptions are unconnected:
* /output_data_node:
* /tf_static
Found 1 error(s).
ERROR The following nodes should be connected but aren't:
* /play_1400020743429896445->/output_data_node (/tf)


Question is, what does it mean by "should be connected", and how do I "connect" them. All of this is running on the localhost.

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