[OSM-dev] Spatial vs. multi-column indexes for points

Florian Lohoff flo at rfc822.org
Fri Sep 12 07:58:08 BST 2008


On Fri, Sep 12, 2008 at 08:20:18AM +0200, Andreas Kalsch wrote:
> Subject: Re: [OSM-dev] Spatial vs. multi-column indexes for points
> 
> > On Thu, Sep 11, 2008 at 08:31:23PM +0200, Andreas Kalsch wrote:
> > > All, thanks for your quick responses!
> > > 
> > > Quad tiles look like a smart way to create an index. So to lookup a
> > > single point or a quad tile, this is fine. But for my application I
> > > need another lookup - by bounding box with any ratio and size. Is
> > > there a way to look up a special bounding box with this index? I
> > > think this will be a little more complicated without conventional
> > > multi-column indices. Hmm, I think you could take a maximum number
> > > of quad lookups which contain the requested box, what do you think?
> > 
> > The code in the api calculates all possible quadtile areas and does a 
> > quadtile in ( x, y, z, a, b, c, d, e, f ) or quadtile between x and y
> > etc
> 
> Can you give me the position of this code in SVN, I am sure will understand it more deeply then.

applications/utils/export/osm2ai/osm2ai.pl

Is a perl variant - look for "sql_for_area"

In the rails_ports its done with a C helper - look in

sites/rails_port/lib/quad_tile/

Flo
-- 
Florian Lohoff                  flo at rfc822.org             +49-171-2280134
	Those who would give up a little freedom to get a little 
          security shall soon have neither - Benjamin Franklin
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 189 bytes
Desc: Digital signature
URL: <http://lists.openstreetmap.org/pipermail/dev/attachments/20080912/6c162c7d/attachment.pgp>


More information about the dev mailing list