[gdal-dev] Re: OGR Select Features by Location...

[estrada.adam at gmail.com]

Joe,
    I am actually using ogr2ogr to get the data in and out of the
database so this is not totally off topic!  Thanks for the update
though...it appears to be working wonderfully.

Adam

On Jan 29, 6:55 pm, Joe Healy <j... at omc-international.com.au> wrote:
> We're probably getting a little off topic, but
>
> estrada.a... at gmail.com wrote:
> > All,
> >     How important is it to create the index for the intersection
> > function I am trying to perform.
>
> It depends on how many of your points are within the bounding box of
> each polygon.
> If the bounding box will reduce the number of point in polygon
> comparisons significantly then it is essential, otherwise a linear scan
> may be quicker if they are all inside.>  We are talking over 15 million LIDAR
> > points already loaded in to my PostgreSQL DB for a single dataset.  I
> > read something that said that each set of 1 million points takes an
> > hour to process when creating the index.
>
> For sets with approx 8 million points someone here ran yesterday, the
> complete loading, indexing and querying took approximately 40 minutes
> per set.
> Make sure you are using copy to insert the data. Email either the
> posgresql performance list or postgis list for other performance hints
> if it is still not quick enough.
>
> Hope that helps,
>
> Joe
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