[OSM-dev] spatial reference

[Jon Burgess]

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.

http://lists.openstreetmap.org/pipermail/dev/2006-September/002059.html

	Jon