# Rtabmap 101 Demo 1.1

**URL:** <https://get-help.theconstruct.ai/t/rtabmap-101-demo-1-1/8714>\
**Category:** RTABMap in ROS 101\
**Created:** [March 10, 2021, 10:36am UTC](https://get-help.theconstruct.ai/t/rtabmap-101-demo-1-1/8714 "2021-03-10T10:36:28Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![xunmengfunder](https://get-help.theconstruct.ai/letter_avatar_proxy/v4/letter/x/a587f6/32.png) [@xunmengfunder](https://get-help.theconstruct.ai/u/xunmengfunder)\
**Post date:** [March 10, 2021, 10:36am UTC](https://get-help.theconstruct.ai/t/rtabmap-101-demo-1-1/8714/1 "2021-03-10T10:36:29Z")

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when i run the code as demo 1.1 suggested，there comes the warning！

[WARN] [1615372355.116498767, 22155.195000000]: /rtabmap/rtabmap: Did not receive data since 5 seconds! Make sure the input topics are published ("$ rostopic hz my\_topic") and the timestamps in their header are set. If topics are coming from different computers, make sure the clocks of the computers are synchronized (“ntpdate”). If topics are not published at the same rate, you could increase “queue\_size” parameter (current=10).  
/rtabmap/rtabmap subscribed to (approx sync):  
 /data\_throttled\_image/compressed,  
 /data\_throttled\_image\_depth/compressedDepth,  
 /data\_throttled\_camera\_info,  
 /jn0/base\_scan

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**Author:** ![xunmengfunder](https://get-help.theconstruct.ai/letter_avatar_proxy/v4/letter/x/a587f6/32.png) [@xunmengfunder](https://get-help.theconstruct.ai/u/xunmengfunder)\
**Post date:** [March 11, 2021, 2:07am UTC](https://get-help.theconstruct.ai/t/rtabmap-101-demo-1-1/8714/2 "2021-03-11T02:07:22Z")

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We can ignore the warning. And execute \* rosservice call /gazebo/pause\_physics “{}” \* to pause the gazebo simulation, then \* roscd turtlebot\_rtab && rosbag play --clock demo\_mapping.bag \* ,everything will be allright. Perhaps the published topics from our gazebo simulation are not match the topics rtabmap\_ros need.

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**Author:** ![albertoezquerro](https://get-help.theconstruct.ai/user_avatar/get-help.theconstruct.ai/albertoezquerro/32/7031_2.png) [@albertoezquerro](https://get-help.theconstruct.ai/u/albertoezquerro)\
**Post date:** [March 11, 2021, 8:51am UTC](https://get-help.theconstruct.ai/t/rtabmap-101-demo-1-1/8714/3 "2021-03-11T08:51:14Z")

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Hello @xunmengfunder ,

Yes, this warning is normal since in this demo we are showing a mapping session from a bag file, so the topics used are not the ones from the simulation (that’s why we pause the physics engine from Gazebo).

Best,

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**Author:** ![xunmengfunder](https://get-help.theconstruct.ai/letter_avatar_proxy/v4/letter/x/a587f6/32.png) [@xunmengfunder](https://get-help.theconstruct.ai/u/xunmengfunder)\
**Post date:** [March 13, 2021, 7:37am UTC](https://get-help.theconstruct.ai/t/rtabmap-101-demo-1-1/8714/4 "2021-03-13T07:37:32Z")

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Thanks for your patient explanation！  
I got a new problem, I install rtabmp\_ros for source code followed the official tutorials([GitHub - introlab/rtabmap\_ros: RTAB-Map's ROS package.](https://github.com/introlab/rtabmap_ros)). When execute command " roslaunch rtabmap\_ros demo\_robot\_mapping.launch rviz:=true rtabmapviz:=false ", an error occurred：points\_xyzrgb process died. But when execute " roslaunch rtabmap\_ros rtabmap.launch rviz:=true rtabmap:=false "，points\_xyzrgb process executes normally. Can you help me with this problem?

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**Author:** ![albertoezquerro](https://get-help.theconstruct.ai/user_avatar/get-help.theconstruct.ai/albertoezquerro/32/7031_2.png) [@albertoezquerro](https://get-help.theconstruct.ai/u/albertoezquerro)\
**Post date:** [March 15, 2021, 9:18am UTC](https://get-help.theconstruct.ai/t/rtabmap-101-demo-1-1/8714/5 "2021-03-15T09:18:45Z")

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Hello @xunmengfunder ,

You don’t have to install **rtabmap\_ros** , it is already installed for you in the courses.