[OSM-talk] Historical Data in OSM database

David Murn davey at incanberra.com.au
Thu Nov 11 00:35:57 GMT 2010


On Thu, 2010-11-11 at 00:45 +0100, Frederik Ramm wrote:
> Hi,
> 
> David Murn wrote:
> > OSM, by its nature, is excellent for retaining historic data, for
> > example if a road is realigned, you have a history that shows how it was
> > realigned, or if a road changes name, there exists a history of previous
> > names.
> 
> 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.

If youre making time-lapse style animations from OSM, chances are you
dont want a historic resolution of 1 day anyway, youre more likely to
want to compare say, 2000 data to 2010 data to 2020 data, and I believe
over time this historic data will exist.  What Im trying to say, is if
you want a long-term history archive, why not use the data that already
exists, rather than adding more data.

David




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