shptree not faster than no index

[John Bolster]

Thank you for your quick response.

In terms of the county outlines, do you think that one county per file, and
selecting which files to use with only a tileindex would be faster than all
counties being in one huge file of over 3000 counties and selecting which
counties to draw using a qix index?

Also, does the qix index on the actual tileindex do anything to speed up the
tileindex?

Thanks,
John

> -----Original Message-----
> From: Frank Warmerdam [mailto:warmerdam at pobox.com]
> Sent: Thursday, September 23, 2004 6:13 PM
> To: John Bolster
> Cc: MAPSERVER-USERS at LISTS.UMN.EDU
> Subject: Re: [UMN_MAPSERVER-USERS] shptree not faster than no index
>
>
> 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,
> --
> ---------------------------------------+--------------------------
> ------------
> I set the clouds in motion - turn up   | Frank Warmerdam,
> warmerdam at pobox.com
> light and sound - activate the windows | http://pobox.com/~warmerdam
> and watch the world go round - Rush    | Geospatial Programmer for Rent
>
>