[OSM-talk] Historical Data in OSM database

[Lester Caine]

David Murn wrote:
>> I think that you, just as almost everyone else in this discussion, are
>> >  wrongly mixing OSM's revision history and true on-the-ground history.
> I understand the difference, but what Im saying is on the small scheme
> of things, with only a couple of years data, that is the current state
> of OSM.  However in 10 years, or 100 years, this 'revision history' will
> be tied in more closely to 'on-the-ground history'.  The key part to OSM
> revision history, is that it will only record future changes, it wont
> record the past.  Therefore, it is good to keep a history to compare
> some time in the future to now, but not as good to compare now to
> sometime in the past.

In reality *IS* there a difference?
At what point does one throw away the revision history data that so and so 
street no longer exists?

Perhaps what is actually wrong IS differentiating between version history and 
'changes to reality'. Just as one needs to be able to move back through a set of 
revisions to an object to correct mistaken changes, moving forward that revision 
history becomes the very data we are talking about. So while being able to EDIT 
revision history is not something one wants to enable, creating 'virtual' 
revision history covering historic changes in parallel with the ongoing 
gathering of that very history is perhaps a way forward? The very tools that are 
needed to review version history also then view historic changes ... the data is 
'orthogonal' to the CURRENT map ... and as time goes by we can fill in revision 
history back in time?

I still think that the 'current' data needs to correctly record the date a 
feature came into existence, but people obviously feel that once it ceases to 
exist then it should be purged from the data. THAT is what I personally find 
unacceptable, and so it's perhaps deciding the rules moving forward that we need 
to agree on initially?

-- 
Lester Caine - G8HFL
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