[OSM-talk] Databases?

Andy Allan gravitystorm at gmail.com
Wed Oct 15 16:18:11 BST 2008


On Wed, Oct 15, 2008 at 3:53 PM, Joseph Gentle <josephg at gmail.com> wrote:
> Hi!
>
> I've been taking a look at the software stack and (especially with the
> intermediate XML formats) I can't help but feel that we could
> represent the map data in a much more efficient format - eg a
> quadtree.

OSM data is already represented in a variety of application-specific
formats. The xml structure is just for interchange, it's expected that
it can/will be converted before use by e.g. renderers, routing engines
etc.

> With the right data structures, it should be possible to
> render maps on client side in realtime. Maps are far less complex
> graphically than most 3d games; and they work just fine.
>
> So how good is postgis?

It's good, for various defininitions of 'good'

> Does anyone know if its performant enough for
> real-time map rendering? Can it do level-of-detail stuff ("fetch all
> data in europe with at least city level significance")?

I'm not sure exactly what you've got in mind, but it's fast enough to
render large areas of maps in sub-second intervals using mapnik, at
least. And it does spatial queries, so you can ask for all data in
Europe, and apply filters and so on.

> Has anyone tried making better data representations?

'Better' is dependent on what you're trying to achieve, but there are
certainly many 'different' representations in use in different
projects.

Cheers,
Andy




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