What is the best mapping/localization package for using pre-made maps?

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The amcl package is a popular choice for localizing within premade maps. However, I've only ever used it to localize within maps I created using gmapping. You could theoretically fill out a nav_msgs/OccupancyGrid message by hand, or through some other method, to generate your map, and then publish it to amcl. However, this may not work how you expect, as the robot's view of the building is percepted only through its laser scan. Anything that is the same height as the laser will be picked up in a scan, including chairs, desks, plants etc. Just inputting walls into a map won't work if there is anything except bare walls within your building.

I would personally recommend improving the odometry and using gmapping to get the map.