[OSM-dev] Multiple layers in the database

Frederik Ramm frederik at remote.org
Sun Mar 16 09:34:12 GMT 2008


> It seems to me that it might be much better to start having the concept 
> of multiple layers in the OSM DB.

I've been talking about this only recently when a guy asked for a
"play area": I said that in the long run we'll have to have different
layers anyway, and then we might also have a play layer.

I think layers will also be interesting when it comes to model stuff
like some ancient Roman buildings or other historic data which would
greatly complicate editing of the "current" data if it would get in
the way all the time.

Of course, millions of open questions remain, e.g. will there be
features that can transcend layers, or links between them (e.g.
feature X on layer A is the same as feature Y on layer B or so).

> Clearly, this would require a tweak or two to the DB (a "layer" value 
> for each object),

Not necessarily - one could also set up different layers on their very
own infrastructure which may not even have to be in the same country
as the original OSM server. Why stuff more and more through that
single bottleneck when there's a good opportunity for scaling here?

Even your idea of "merging" is perhaps not so important; if we had
good layer support across the toolchain, we would not even have to
merge everything into one "main" layer.


Frederik Ramm  ##  eMail frederik at remote.org  ##  N49°00.09' E008°23.33'

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