[OSM-talk] Potlatch, dual carriageways, and a broken changeset

[Michal Migurski]

On Nov 6, 2009, at 6:38 PM, Russ Nelson wrote:

> Michal Migurski writes:
>> instead make sure that multi-level undo is completely bulletproof.
>
> To make life more interesting, OSM editing goes on concurrently, and
> yet nearly everyone who is editing is editing a chunk locally.  So OSM
> is episodically being synched with chunks of data we call a
> "changeset", but which also includes the concept of an "edit conflict"
> meaning that two chunks have been edited at the same time.
>
> Simultaneous editing of geodata is currently not a solved problem.
> Even less solved is the concept of multi-level undo, much less
> single-level undo.  Within an editing session?  Sure.  Within your
> chunk of data?  Sure.  But not outside that.


I think this further underscores the difference between save mode and  
edit mode. Save mode is more like traditional desktop document  
editing, and the undo history need only be consistent with what you're  
doing in your own session. In this case, it should be possible to  
ditch the locked ways and instead make sure that the local document is  
fully self-consistent and undo-able.

For live mode, clearly an undo feature would introduce more trouble  
than it's worth, for everyone involved in editing a particular area.  
There the presence of locked or ghosted ways as in the current  
Potlatch does make sense, but I do think the terminology and visual  
presentation could be tweaked a bit. I know what you mean about this  
not being a solved problem, and given how much time I spend with SVN,  
Git, etc. I'm pretty aware of how hard it can be to merge concurrent  
edits on the same resource.

-mike.

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