When someone changes coordinates, the diff (e.g. https://www.wikidata.org/w/index.php?title=Q23311&diff=108698259&oldid=103394905) shows what the coordinates changed from and to, but it's hard (near impossible) to check whether the change was good or bad without manually looking up both the old and new coordinates on a map, which is time consuming to do. I usually can't be bothered to and I imagine most other people are the same, so I think it would be useful if the diffs included a little map.

This seems like something that https://maps.wikimedia.org/ (https://www.mediawiki.org/wiki/Maps) would be useful for. Right now it doesn't allow access from wikidata.org though.

I think this could be turned into a gadget fairly easily. I was able to insert maps using OSM's tiles (which shouldn't be used) with a bit of code I quickly put together (below), which seems to work, although it definitely needs some improvements, including:

• a different source of tiles - can we get access to maps.wikimedia.org, or is there some other source that can be used?
• proper attribution - should be easy to add, but depends on the tile source
• Leaflet should ideally not be loaded from an external source - is there a copy of Leaflet hosted somewhere on Wikimedia servers that can be used? or perhaps another slippy map? (I do like Leaflet though...)
• it doesn't check that the globe is Q2 - checking should be easy, but what about when it's not Q2? I seem to recall that GeoHack can display Mars maps, but I haven't looked into it
• it currently always uses the same zoom level - it seems like it should be possible to come up with an appropriate zoom level using the precision of the coordinates, but I haven't looked into that either. A quick search did find http://wiki.openstreetmap.org/wiki/Zoom_levels though