What's the purpose of topic "/map"?

[wt70707]

Here I have a scenario of two robots who have LIDARs that will SLAM to have two maps: robot1/map, robot2/map. I remap "world" to "robot1/map" which is the reference of the other robot, and recap "align" to "robot2/map". I cannot figure out how can I deal with "/map". Anyone can help me out?

My purpose is to run multiple robots in "one common map". It seems I can put the tf of "world" to "map" (renewed by "align"), but I cannot get correct "location" of robot2, which the transform should be "ground->robot1/map->robot2/map->robot2/odom->robot2/base_link->robot2/laser".

Thanks,
Tao Wang