shptree not faster than no index

[Frank Warmerdam]

John Bolster wrote:
> Hi all,
>
> I'm noticing there doesn't seem to be any difference in speed between having
> *.qix files vs. not having them. I'm wondering if I'm doing this right.
>
> My data is from tiger and is in shapefiles. I'm only dealing with county
> outlines right now. They are each in a separate folder, each state's
> counties are in one state folder. There's a tileindex on them all at the
> root of the tree.

John,

The impression I get is that you have exactly one county polygon per shapefile.
Is that right?  A .qix won't help because it is used to more quickly select
the subset of shapes in a shapefile based on the extents.  If you only have
one shape per file then it can't help.

Of course, the tileindex should allow you to quickly select the county
files you want.  But a more efficient approach would likely be to have one
shapefile with a .qix with all your county outlines in it.

Best regards,
--
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