[OSM-dev] Timestamp in PBF files

[Jochen Topf]

On Tue, Nov 20, 2012 at 08:40:39PM +0100, Frederik Ramm wrote:
> On 20.11.2012 20:12, Jochen Topf wrote:
> >I guess the timestamp is somehow supposed to say which state of the OSM
> >database this file represents.
> 
> Yes. Bascially "whatever was in Osmosis' state.txt file at the time
> this file was created".

Thats not a definition. I create PBF files all the time without a state.txt
file around. 

> >How is it supposed to work in history files?
> 
> I think it would make sense to have a a comparable timestamp in
> history files. Currently there's no software that would be able to
> patch history files with freshly downloaded diffs so the discussion
> is rather academic though.

Sure. Osmium can do that.

> >Do we need two timestamps to define a range for history files?
> 
> I'd suggest to wait until someone has an application that needs
> this. I'm a bit wary of throwing this discussion wide open because
> before too long we'll have all sorts of people suggesting helpful
> optional enhancements to the PBF format ("while we're at it, can we
> maybe do X") and then nothing gets done again.
> 
> All *I* want is one extra timestamp, and I would start using it
> tomorrow, it's not academic, there's software that would process it,
> there's a clear benefit to users. I'd prefer to use a standard but
> in the absence of an existing standard I'll just make something up
> and use that. (But we've seen how well that works - I did make
> something up for testing and Marqqs expected something else.)

And what I am saying is that we should think this through so that we don't
have the same problem again tomorrow.

Jochen
-- 
Jochen Topf  jochen at remote.org  http://www.remote.org/jochen/  +49-721-388298