There is no map showing in the rviz window when launching the simulation.launch file.

[Hello970]

Device Environment: Ubuntu20.04, ROS Noetic
After launching the simulation.launch file, it first lists the error:

[ERROR] [1682304711.927218665, 0.340000000]: No p gain specified for pid. Namespace: /gazebo_ros_control/pid_gains/front_right_wheel
[ERROR] [1682304711.927957838, 0.340000000]: No p gain specified for pid. Namespace: /gazebo_ros_control/pid_gains/front_left_wheel
[ERROR] [1682304711.928716595, 0.340000000]: No p gain specified for pid. Namespace: /gazebo_ros_control/pid_gains/rear_left_wheel
[ERROR] [1682304711.929464850, 0.340000000]: No p gain specified for pid. Namespace: /gazebo_ros_control/pid_gains/rear_right_wheel
At the same time, there is nothing showing in the rviz with world frame. When I changed the frame to the base_link, it can show the car model. However, there is always no map. In Gazebo, it can show the map and car normally. When I operate the car with the keyboard, the car can move successfully.

[hrxsd]

@Hello970 I had the same problem, did you solve it?

[LiuL0ngl0ng]

@Hello970，@hrxsd，If you wang use it in noetic, you only need to modify two places,and this problem will be solved:
1、putn/src/scout_simulator/scout_description/urdf/scout_v2.xacro on the twelfth line:
<HDL-32E parent="base link" name="velodyne" topic="/velodyne points" hz="10" samples="440" gpu="false" lasers="32" max range="100"
<origin xyz=o.3" rpy="o o o" />

modify as:
<xacro:HDL-32E parent="base link" name="velodyne" topic="/velodyne points" hz="10" samples="440" gpu="false" lasers="32" max range="100"
<origin xyz=o.3" rpy="o o o" />
</xacro:HDL-32E>
2、putn/src/putn/putn_planning/src/PUTN_vis.cpp on the 52th line:
map_vis.header.frame_id = "/world";
should be modified as:
map_vis.header.frame_id = "world";

[Usaywook]

I also have the same problem. Hello @LiuL0ngl0ng, I tried to modify the two places that you advised. However, I could not solve the problem. Is there anything additional I need to do? Has anyone else faced the above problem and solved it?

For my case, I have lidar in Scout but not scan messages in ROS.

[Usaywook]

I solved this issue by installing velodyne_gazebo_plugins

sudo apt-get install ros-melodic-velodyne-gazebo-plugins