To find map coordinates for your Xiaomi robot you can try the offline viewer which is included in the OH source.
I made it now also as standalone, you can get it here
2020-08-14 new version (incl calc and zone selection): http://verpaalen.com/openhab2/roboMapViewer2.5.7.zip
2020-09-22 new version (fix command format & obstacles): http://verpaalen.com/openhab2/roboMapViewer2.5.9-1.zip
you run it like this
java -jar RoboMapviewer2.5.9-1.jar (assuming java is in your path, and the viewer is in the current dir, otherwise add the paths appropriately)
Clicking in the graph should give a coordinate in the text window, dragging mouse will give the zone
Note: The rrmap files are saved by the binding in the userdata/miio folder.
Note that the rrmap files are only saved when debug logging is enabled (
log:set debug org.openhab.binding.miio )