Can I subscribe a new topic in a subscribe callback?

edit

Although creating and destroying a subscription at runtime -- as @miura suggests -- is certainly possible, I would probably suggest to use ros::topic::waitForMessage(..) instead.

See #q270298 for an earlier Q&A about it, with an example and a link to the API documentation.

(and see #q240768 for a similar question or perhaps even a duplicate of yours, although it's about time, not distance)

I don't know how to publish every 1 meter, but I will suggest two approaches that might be useful. ( If there is a way to control the publishing interval, I'd like to know too! )

1. subscribe every 1m

1. create a point cloud subscriber for every 1m
2. shutdown the subscriber in the point cloud when the point cloud callback is received.

Although there is a load to keep publishing realsense, I should be able to reduce the frequency of callback processing to almost every 1m.

ref shutdown method: http://docs.ros.org/en/melodic/api/ro...

2. Change the period

You may be able to drop the publishing cycle of the point cloud from 60hz. In the case of camera images, I was able to drop it to 6hz by updating the fps parameter such as color_fps.

https://github.com/IntelRealSense/rea...