Florian Lohoff wrote:
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/
or for the rails version
http://trac.openstreetmap.org/browser/sites/rails_port/lib/quad_tile.rb
Shaun
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