|Group: Lifecycle prefix|
|This tag page describes a namespace. Use it as no: lifecycle prefix rather than a simple tag.|
The no: lifecycle prefix can be added to tags that relate to features that don't exist but have an high probability to be re-added by a non surveyed edit because they can be seen on commonly used imagery or import sources. In most cases, in OSM, if you find a object in the database that don't exist on the ground, whether it existed or not, is an error or not, you should just delete it. But in some rare circumstances, when those features still appear in outdated sources still used to enter data in osm (old imagery, import sources, etc.) you can use this tag to warn other mappers not to re-add those features.
How to tag
Add the namespace "no:" to all keys which are no longer relevant to the current state of an object without changing the geometry (let it a node if it was a node, a way if it was a way). You should treat all the tags on an object as a set of facts about the object, and prefix the keys of those facts which are no longer true as a result of being non existent.
Adding a note=* to explain why you just didn't delete the geometry is highly recommended, else, someone might just delete everything again.
This tag might be later used to detect intersection with other geometries to detect added feature that shouldn't have been re-added
usage of (maybe) similar concepts
- removed:* ~1000 use in the db as of 11/2014. Most tag used are removed:power=* and removed:design=*
- demolished:* ~1000 use in the db as of 11/2014.
- demolished_* ~50 use in the db as of 11/2014.
- no:* ~100 use in the db as of 11/2014.
- was:* ~4500 use in the db as of 11/2014.
- was_* ~30 use in the db as of 11/2014.
- old:* ~200 use in the db as of 11/2014.
- former_* ~500 former_name and 100 former_* use in the db as of 11/2014.
- former: ~100 use in the db as of 11/2014.
- gone:* ~40 use in the db as of 11/2014.
Alternatives for the purpose of this tag
It should be possible to use the history of deleted objects to detect if they are re-added by someone. However no practical tools to query history have been made available. Therefore, this solution is a temporary workaround that could later be replaced by history based comparison.
Notes could be added to warn people not to add deleted objects.