[geos-devel] Indexing question from a newbie

Sudipta Sarkar ssarkar at forestone.com
Fri Jul 7 13:22:35 EDT 2006

Hi Paul,
Yes we do have PostGreSQL and PostGIS and I know we can do it through 
PostGIS but the current requirement precludes use of PostgreSQL and so 
it has to be from scratch. Sorry for wrong choice of words but my tiles 
may not be regularly sized. So am i to assume then that SRTree will be 
more efficient?
Is there any tutorial or example anywhere I can look at?

Paul Ramsey wrote:
> I am not a programmer, so I can't give you code snippets. I can tell 
> you that if your tiles are regularly sized and regularly spaced (as 
> the term "tile" hints) probably the quadtree will be marginally more 
> efficient/faster.
> WRT your actual problem, depending on your implementation requirements 
> using PostGIS/PostgreSQL rather than coding from scratch will 
> certainly be easier. The suitability of that kind of solution 
> obviously depends on where you are going to deploy the final product, 
> of course.
> P.
> Sudipta Sarkar wrote:
>> Hi All,
>> I am trying to use GEOS to create envelope geometries for a bunch of 
>> different tiles and create a spatial index based on these geometries. 
>> The purpose is to select features lying within a particular tile 
>> based on an initial query on the spatial index of these different 
>> tiles. I am a complete newbie to GEOS so was hoping if anyone can 
>> suggest as to which index amidst Quadtree and SRTree will work best 
>> for my purpose. It will also be helpful if anyone can point me to any 
>> example script in C/C++ that uses GEOS to build indexes and query them.
>> Any help is appreciated.
>> Thanks
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