As we have seen in the previous section, there are some devices (such as stereo cameras, 3D laser, and the Kinect sensor) that provide 3D data, usually in the form of point clouds (organized or not). For this reason, it is extremely useful to have tools that visualize this type of data. In ROS, we have rviz, which we will see in the following section, that integrates an OpenGL interface with a 3D world that represents sensors' data in a modeled world. To do so, we will see that, for complex systems, the frame of each sensor and the transformations among them is of crucial importance.
With roscore running, we only have to execute the following code to start rviz:
rosrun rviz rviz
We will see the graphical interface in the following screenshot:
To the left, we have the Displays pane, in which we have a tree list of the different elements in the world, which appears in the middle. In this case, we have some elements that are already loaded...