Map offset/move - a few questions


Have a few questions regarding map offset or map re-alignment.

  1. how do I know who moved/how much movement for a particular area?
    I regularly go through an area in and around Kuala Lumpur to edit/clean up (crossing ways, building and the like) that was probably done by newbies. It is tedious work but it is bearable in order to get a routable map. However, I do notice that sometimes alignment of map and bing tracings are pretty big. I presume that newbies moved the map ( I did once, except that it is in a remote area, not a densely packed area with many many highways). On the otherhand, if it is a legit realignment to surveyed gps position etc etc, how do I know not to recorrect the highway tracings?

  2. any features in JOSM/others that would realign the nodes the same amount the map is realigned?
    Let say I can get accurate points/ways from geodetic surveys, do I need to realign every nodes that gets out of position on the map? What size of map area will be realigned if I click map offset in JOSM?


If you enter a map offset in JOSM for any foto layer, I think it affects the whole layer at all.

So the best way to see how accurat aireal images are alinged is to compare it with public or own GPS tracks that have been recorded and eventually been uploaded to the OSM server.