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I am running gmapping on husky bot with hokoyo scanner in gazebo simulation environment. I am experimenting with gmapping in an empty world. Gmapping does not create any map and the map frame jumps around. Why does gmapping not create a map or mark cells as vacant if the laser scanner is not detecting any obstacles. And if the laser scanner can't see any landmarks, why is the map frame not equal to odom frame?


Originally posted by HassanNadeem on ROS Answers with karma: 71 on 2015-02-23

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If there are no obstacles in the world, the laser will not reflect off of anything and give no response. This is an error condition which may have several causes (such as absorptive bodies) and the data cannot be treated as having been cleared to max range. Thus without any obstacles the laser is always reporting no data and gmapping cannot build a map. You can update the configuration to make this work, but it's a very specific edge case which is rarely encountered in the real world and can lead to false negatives on obstacles.

I expect the reason the map is jumping around is that it's trying to optimize based on close to zero data. Almost any point is equally likely so as gmapping samples possible locations different ones win out due to noise in the system.


Originally posted by tfoote with karma: 58457 on 2015-02-23

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