How to undelete a change

As a long time user of OpenStreetMap I keep a way of accessing an old editor (Potlatch 1) open as that had an undelete function. However, I would not recommend that approach in general.

The best way to approach this is to use JOSM.

There are a fairly sensible set of steps, but they are not particularly clear, partly because the interface for accessing them has changed from time to time. You may need one or more of the following plugins : reverter, changeset manager and undelete. (Unfortunately, as I have them all installed I'm exactly sure which one does what). If you are not familiar with JOSM it is best to ask someone else to do it for you: the learning curve required on your behalf may be totally disproportionate to the effort required by an experienced user.

As you already know identifying the changeset (for complete reversion) and individual object ids (for minor undeletes) is the most useful information to start with. In your case the deleted object is a nodes: 356756834. The other tower looks fine, although it is attached to a road: 356756961. So this is a simple case and the undelete option (on JOSM File menu) can be used.

1. Select File|Undelete object ...
2. Enter "n" followed by the node id (aside to JOSM developers: this dialog should be re-designed to provide a selection list for object type as the requirement for an object type prefix is non-intuitive), i.e., "n356756834"
3. Select the "Separate Layer" option. (This helps if anything goes wrong).
4. Click OK.
5. Check that the object is as you expected.
6. Upload back to OSM.

You can do the same thing with Changeset Manager (overkill for this example) which hides away under the Windows menu.

I've gone and undeleted the object, detached the other tower from the road and tweaked their positions a bit (these came from GNIS so positional accuracy is not always fantastic).

In fact the names of these transmitters seem completely at variance with information on wikipedia (KRTS is given there as being in a mountainous region of West Texas) and there is only one tower visible on Bing imagery). An inspection of the wikipedia article on KROI suggests part of the problem: the GNIS import is so out-of-date as to be worthless. So I shouldn't have really undeleted this node as you actually inadvertently improved the map!