Using Makers Array in rviz

asked 2013-08-15 03:46:45 -0500

micheal
121 ●9 ●10 ●16

For my laboratory project, I have to use markers arrays in rviz to show the movement of satellites around the globe. The parameters of satellites are changing constantly. I have to represent every satellite in spherical coordinates for 3D movement. I have successfully been able to publish all the 3 parameters of every satellite on a topic "menutopic". Now I do not know how can I represent the satellites as markers array in rviz with constantly changing parameters.

answered 2013-08-19 01:14:38 -0500

Martin Günther

11816 ●82 ●159 ●198 https://www.dfki.de/en...

There's a good tutorial on Markers on the ros.org wiki; make sure to go through that first.

Some things to watch out for in general (otherwise the markers won't be displayed):

set the alpha value (marker.color.a) to something non-zero
you have to specify a valid quaternion as orientation (e.g., marker.pose.orientation.w = 1.0)

Some more specific answers to your question:

You need to convert the spherical coordinates into a geometry_msgs/PoseStamped, and put that into marker.pose.
You can either publish each marker in an individual message and publish them on some topic of type visualization_msgs/Marker, or put several of them into a MarkerArray and publish them on a topic of type visualization_msgs/MarkerArray. The latter is more efficient than the former, but for your use case either should work.
Constantly updating the position of each satellite works like this: You set the namespace of all markers to the same namespace (e.g., marker.ns = "satellites"), and give each satellite a unique id (e.g., marker.id = 23). Whenever you want to update the pose of a marker, just publish another Marker message with the same id (it will overwrite the previous one). Even if nothing changes, you should re-publish all existing markers regularly.

In order to add text/name to a marker in RViz, just add a second marker of type TEXT_VIEW_FACING and fill out the text property.