group topics with diferent publishing rates

edit

wow, no actually i just saw that one after i registered :S

will try with message_filters since it has also an example, i will try work with that and see if it works.

with the TF you mean getting an actual location and move it back to match with the image?

with the TF you mean getting an actual location and move it back to match with the image?

yes. You don't need to 'move it back' yourself though, that is exactly what TF is for. It'll lookup the pose at a time in the past you provide, and then uses that to transform your data.

Please also see the Time travel with tf2 (Python or C++) tutorials.

one unrelated technical question (i found only problems about not processing in a fork and so.)

Since i will work with messages from various topics and convert them into another message type before publish, where should i process them before publish since it will take some time to process?

That is really actually a new question. If you are worried about throughput, you could consider making your callbacks thread safe and using an AsyncSpinner. Alternatively, you could look into maintaining a queue and a pool of workers (which is essentially the same, but you have more control).

that's what i am using

    ros::AsyncSpinner spinner(4); // Use 4 threads
spinner.start();

while (ros::ok())
{
    SAPObject.publishReduced();
    loop_rate.sleep();
}

return 0;