A note-writer with local knowledge has given an exact location of a junction, accurate to 1m. I want to move the junction node 5 or 10m to that location.
It looks like this is difficult in JOSM and so perhaps impossible in iD?
(This may be obsessional accuracy (here I could do it by eye), but I’ve had the same question in other contexts, too, where it’s mattered more.)
You cannot set a precise lat-long in iD. The best you can do is to open the “measure tab” (Ctrl+shift+M) and move the node manually to the best of your possibilities. You can also select the node and use shift+keyboard arrow to slightly move it.
In JOSM you can add a node with precise coordinates in many formats with Shift-D.
iD was intended as a low threshold editor mainly for beginners, became more mighty in the meantime, but is still less suited for more sophisticated actions.
OSM ID:
Create a WP at the new node position. You can do it with an app or some online tool, export to gpx, KML or geojson.
Go to OSM ID, load the WP in custom layers, you will get a small blue circle that will show the created WP, find the node of the junction, take it and move it to the center of the blue circle.
VESPUCCI:
Touch the node of the junction, position tool and manually add the coordinates of the new position.
Level0:
Copy the node ID, load it into Level0 and manually modify the coordinates.
JOSM utilsplugin2 adds an option to place a node at the coordinates you want, use it. Afterwards, select the old node, then the new one (order is important) and use “replace geometry” in the menus.