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

[Shaun McDonald]

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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