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Warning "No map received" occurs.

asked 2018-07-24 09:03:10 -0600

Miaow gravatar image

Hello.I'm trying to use slam_karto.

But when I try to see the visual map in the Rviz ,the map model warns 'no map recevied'.

I can see the LaserScan.And the dataset can run correctly on 'gmapping slam_gmapping.

I'm sure the topic name is used rightly.

My step:

rosrun slam_karto  slam_karto
rosbag play catkin_ws/data/inter.bag

When I play the inter.bag,slam_karto prints these:

LaserRangeScan contains 180 range readings, expected 181
LaserRangeScan contains 180 range readings, expected 181
LaserRangeScan contains 180 range readings, expected 181

Up to now , I still confuse how to use slam_karto to run dataset.

Can you help me?

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It seems you dont have karto configured correctly.

stevemacenski gravatar image stevemacenski  ( 2018-07-24 19:23:06 -0600 )edit

Do you means I dont install karto correctly?I just clone karto_slam from github not open_karto,is it wrong?

Miaow gravatar image Miaow  ( 2018-07-24 20:12:17 -0600 )edit

Karto is fine but look at the error you're seeing. What does it mean?

Hint: some of the meta data in your laser scan message is probably incorrect. Here's where your error lies

stevemacenski gravatar image stevemacenski  ( 2018-07-25 00:38:52 -0600 )edit

Thank you a lot!I think that's the key! I dont find corresponding dataset,so I download from there and transform '.clf' to '.bag'. Could you tell me where I can download the right dataset?Thanks!

Miaow gravatar image Miaow  ( 2018-07-25 00:47:47 -0600 )edit

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answered 2018-07-25 01:09:50 -0600

(moving to answer so I can have more characters) I think you need to change the expected number of readings, clearly its off by 1. Alternatively, you can turn off this check since you have installed from source by commenting it out. My guess is that you're not getting the right number of readings and that checker is throwing out all the data. Your options are to 1) configure karto for the right number 2) pre-process the bag file data to have the meta data updated or add a 0 reading at end 3) comment out the check and let it pass with 1 less than expected.

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Thanks for your attention and patience! I take your 2nd suggestion and solve it!

Miaow gravatar image Miaow  ( 2018-07-25 01:27:33 -0600 )edit

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Asked: 2018-07-24 09:03:10 -0600

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Last updated: Jul 25 '18