What is the best approach for rviz a mecanum wheeled robot?

edit

From what I understand, the package uses dwa_local_planner which is possible to plan a path using sideways movement, what I need is to map an area using sideways movement manually, commanded by keyboard or virtual joystick. Or am I missing something here?

Then I do not quite understand your question. What are you trying to do? If you want to teleop a meccanum wheeled robot, you can use any existing teleop package, e.g. written for the PR2, since it does not matter if it is meccanum wheel or not, as long as it is holonomic.

Yes I want to teleop a mecanum wheeled robot while also simultaneously do mapping, but I haven't been able to convert the encoder data into sideways movement that can be visualized using Rviz. What I've done so far is control sideways movement without Rviz visualizing it.

I am a bit confused about where the problem lies. If you already have a controller, and this publishes odom correctly for forward/backward, you can use the same frame to publish the sideways movement (just set the y axis instead of x).

tried that, but I think the way odom works is just one dimensional, or so what I've observed so far. I don't know if I'm wrong but I think to do sideways movement, it needs additional fixed odom frame which rviz doesn't allow. e.g rviz will only fix odom_frame but won't fix odom2_frame