Duplicate nodes in two un-closed ways
Description (last modified by )
In validator, there are two (or perhaps three) types of duplicates listed under "Duplicate nodes in two un-closed ways".
First are duplicates, where all nodes are part of some unclosed ways (this is what I expect to see there)
Second are duplicated nodes, where none of the nodes are part of any ways (basicaly duplicated POIs). These should be in a separate category (named something like "Duplicated nodes not in a way"), so you can distinguish those two apart.
Third could be nodes, where some of the nodes in the duplicate set are part of unclosed ways and some of them are not. I am not sure whether these should be put into first category, or have some separate category for it.
In real data this is often result of area with duplicated upload where you have removed duplicated ways (and any tagged nodes, like crossing, will be left behind) and if there is only one node from the duplicate set being part of some way, the fix is to delete all the others not being part of any way.
Second problem is that there is no "fix" button in this category (for myself I solved it with a patch, but perhaps others may like to use this feature too). There are many cases where you want to fix up some import, where either waterways or highways are uploaded in a manner that any crossings or connections do not share a node, but each way have private copy of node with same coordinate - there is no other function that will allow fixing those type of bugs. While there is risk of someone dumb damaging the data by connecting unrelated ways together, this Fix feature can be very useful (and safe), if you run it on result of validation of carefully selected subset of the data (complex search expressions can be good at selecting such subset)
Perhaps some heuristic as whether to enable fixing in this case or not is whether the validator was run on a selection different from all the data.
For Duplicated POIs there should be a button to automatically fix this type of bugs - since merging all the nodes basically mean delete all but one copy of the POI.
Technical note: there can be more duplicated nodes (and corresponding ways) than two, so the name should be "Duplicate nodes in _multiple_ un-closed ways"