Dedicating your data to the public domain - how to?

Mike, I think you making far too much work for yourself.

The PD tick box has a long and controversial history, including some technical/layout hickups that essentially imply that we will not be able to actually use your choice in a legal context.

If we ever want to provide a "PD" extract of the OSM data we would probably go back to the contributors and ask specifically for such permission (it would probably require going through the CT process of adding a further distribution licence too).

I would suggest that any discussion on this is moved to one of the mailing lists or forums, the help system is not really suited or intended for policy discussions.

When you contribute, you contribute on the terms of the CTs (http://www.osmfoundation.org/wiki/License/Contributor_Terms), these give the OSMF the (non-exclusive) right to distribute the data under the licences that are determined in a democratic process by the active mappers.

In other words you are free to make any data you have provided seperatly available under any licence you choose. Trying however to seperate your contributions in the OSM database from those of others doesn't make legal nor technical sense. Latest at the point in time when other contributors edit your data they become intertwined with the work of everybody else.

During the licence change we had to undo some of this and while it was doable, it was not a pretty sight. If you believe that OSM data should be available with different licences than it is today then you can engage the community and try to get further distribution licences added. That however is no small task.

Please simply contribute on the same terms that everybody else does.

I am not sure what exactly you are trying to do, but the PD flag is deliberately nonrevocable. Once you have given your data to the project, you can not take the license back, as otherwise it would be impossible to build upon your work if you could revoke your license at any time. Given the interconnectedness of map data, this would entirely defeat the purpose of a collaborative crowd sourced project like OSM.

If you read for example the CC0 license which is aiming to emulate public domain, it states "To the greatest extent permitted by, but not in contravention of, applicable law, Affirmer hereby overtly, fully, permanently, irrevocably and unconditionally waives, abandons, and surrenders all of Affirmer's Copyright and Related Rights and associated claims and causes of action, whether now known or unknown (including existing as well as future claims and causes of action), in the Work..."

Also the OSM contributor terms state: "You hereby grant to OSMF a worldwide, royalty-free, non-exclusive, perpetual, irrevocable licence to do any act that is restricted by copyright..."

So no, you cannot revoke the license and this is unlikely going to change. You can however stop contributing any future data if you don't like the license. If it is only the PD flag that is bothering you and you are fine with the ODbL, then as Simon said, this flag is likely legally meaningless and so of no real consequence. The best thing in that case is simply to create a new account and make future contributions in the new account without the PD flag set.

Reverting your changes in JOSM does not really help, as the data remains in the history and so anyone who thinks those changes are useful can always revert your revert, reinstating your data under the license.

If there are specific reasons why you really do need to remove your data, e.g. because you didn't have the license to give to OSM in the first place, or there are other good and valid reasons for the data to be removed, you would need to contact the OSMF Data Working Group, who do have the ability to permanently purge data from the database, but won't do that lightly.