[OSM-dev] spatial index - B-Tree over z-order curves vs R-Tree over GIST
pablo.platt at gmail.com
Thu Apr 9 11:33:55 BST 2009
On Thu, Apr 9, 2009 at 1:30 PM, Frederik Ramm <frederik at remote.org> wrote:
> pablo platt wrote:
>> Is the tiles resolution predetermined
> Yes, it is 32 bits.
> We take lat and lon and scale them to a 16 bit value each (this means we
> get 0.0055° precision in the East-West direction and 0.0027° precision in
> the Norh-South direction). Then we use first bit of the 16-bit longitude
> value, then the first bit of the 16-bit longitude value, then the second of
> each, and so on, to build a 32-bit tile value.
I've read http://wiki.openstreetmap.org/index.php/Name_finder but now I
understand how you do it.
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