JOSM/Plugins/Undelete
From OpenStreetMap Wiki
This plugin allows to undelete objects.
How to use
- Find out the id. of the object
- Choose "File" → "Undelete Object"
- Enter the id. and type of the object
- Upload the changes
The object will be undeleted preserving the old id.
What if I do not know the id.?
The current API does not allow to search for deleted objects. Anyways, it is possible to use the undelete function of potlatch because it uses a different access to the database.
You can try to find the lost objects in older dumps of the database to find out the id.
If you know who created/changed/deleted the object and when, you can view that user's changeset history to find the id's of all objects affected by each changeset.