[OSM-dev] spatial reference
jburgess777 at googlemail.com
Mon Jul 2 22:17:07 BST 2007
On Mon, 2007-07-02 at 18:44 +0200, Martijn van Oosterhout wrote:
> On 7/2/07, Artem Pavlenko <artem at mapnik.org> wrote:
> > Hello,
> > I had a chance to go through tile.openstreetmap.org implementation and I'd
> > like to suggest some improvements.
> > At the moment we store x,y,z and there is a key(x,y,z). I think we can
> > improve by introducing spatial reference (also known as quad key etc) and
> > this is exactly what MS VE, Oracle and others are using. There are a few
> > benefits but the main one is
> > that standard b-tree index will 'cluster' tiles spatially, resulting in
> > better I/O. It will also simplify and reduce table size a little bit.
> Look in the wiki for quadtiles, I think it resembles your proposal a lot.
> As for speed inprovement, do think it will speed it up or have you tested it?
> Have a nice day,
You may also be interested to take a look at a thread from last year
where Nick Hill tried to extend this idea by interleaving each bit of
x/y to achieve an even higher denser bit density / smaller index.
Subject: [OSM-dev] Proposal: Database accelerator and dirty tile marker
based on simple algorithm.
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