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hector_slam: how to load a saved map (and perform localization)

asked 2012-11-05 03:38:36 -0500

randaz gravatar image

Hi, I read the tutorial about creating a new map with hector_slam and save it. My question now is: how to load a saved map and use it for localization? (thus substituting amcl) Thanks

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that is exactly what I was searching for!

Procópio gravatar imageProcópio ( 2012-11-21 08:46:54 -0500 )edit

I am also really interested in doing that, but still new in ROS. Is there any update?

quentin gravatar imagequentin ( 2015-11-08 20:41:28 -0500 )edit

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answered 2012-11-05 14:33:48 -0500

Yes, this is currently not supported. I meant to add it add some point (shouldn't be too difficult), but I'm quite stuffed with ToDos, so I probably won't be able to implement that functionality in the foreseeable future.

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thanks for the nice work man! I am amazed on how well it works with my bad odom robot. implementing localization with a loaded map would be perfect. could you point some direction on how you would do it? I might give it a try! thanks

Procópio gravatar imageProcópio ( 2012-11-21 08:45:49 -0500 )edit

As long as one doesn't use multiple map resolution levels it shouldn't be too hard. Essentially, the map would only have to be read via some method at startup and not get updated later. The most annoying (even if not really complicated) thing is probably setting the transforms correctly.

Stefan Kohlbrecher gravatar imageStefan Kohlbrecher ( 2012-11-27 02:27:51 -0500 )edit

Any progress on this yet? I'm trying to use the odom data from hector slam with a pre-saved map. Then I will use move_base with it.

musiqsoulchild gravatar imagemusiqsoulchild ( 2015-03-17 16:26:56 -0500 )edit

Just brainstorming and was wondering if I just loaded in a presaved map using map_server and remapped the /map topic created from hector slam to something else. Then I could use the localization from hector slam and use a static map. Any comments on this approach?

musiqsoulchild gravatar imagemusiqsoulchild ( 2015-03-17 17:21:49 -0500 )edit
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answered 2017-02-22 18:13:33 -0500

tb12 gravatar image

I have gotten AMCL to work with the LaserScanMatching node using just a Lidar. I set the fixed frame in LaserScanMatching to odom and the base frame to base_link. In AMCL it uses the intuitive parameter names, odom frame is odom, base frame is base_link. The tf tree then goes map -> odom by amcl, odom -> base_link by laser_scan_matching.

I will try to get this working with hector slam also as the odometry, if anyone has gotten that please let me know how!

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answered 2012-11-05 22:43:45 -0500

randaz gravatar image

Thank you for your answer. So amcl is the only way to perform localization on a saved map? But in this case I have to use odometry, which is not reliable on our custom robot. Is there any other way to perform localization on a saved map using only laser data? PS: I think that is a pity that this feature is missing in hector_slam, the mapping results are really good and it would be really interesting to use it a complete navigation demo.

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http://www.ros.org/wiki/laser_scan_matcher can provide something like odometry based on laser. I am not aware of another localization package than amcl.

dornhege gravatar imagedornhege ( 2012-11-05 22:46:14 -0500 )edit
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Please do not use answers for comments or discussion. This is not a forum. Instead please either edit your original post or use the comment functionality.

Lorenz gravatar imageLorenz ( 2012-11-05 23:01:27 -0500 )edit

@dornhege, I took a look and think laser_scan_mathcer actually computes odom based on laser measurements only and not on matching scans with a previous built map. maybe laser_scan_matcher + amcl might work.

Procópio gravatar imageProcópio ( 2012-11-21 21:27:00 -0500 )edit

Correct. Odometry is what was missing at his robot.

dornhege gravatar imagedornhege ( 2012-11-21 22:33:57 -0500 )edit
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answered 2012-11-05 04:01:55 -0500

dornhege gravatar image

My guess is that this is not possible, so you'll just save the map as any other occupancy map and use amcl.

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answered 2018-09-26 09:21:44 -0500

AndyZe gravatar image

There's a PR that claims to provide this capability now: https://github.com/tu-darmstadt-ros-pkg/hector_slam/pull/45

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Asked: 2012-11-05 03:38:36 -0500

Seen: 2,587 times

Last updated: Sep 26 '18