<html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"
data-hsystem="true"></head><body><style>p{margin: 0;padding: 0;}</style><p>in
2011 / 2012, I was lead technical implementor for a study of land use, jobs,
housing, energy use and transportation in California, using a 150 meter grid.
The 'grid' was a refrerence set of geometry, each resembling a box, in
EPSG:3310. It is reference because the ID of each grid cell is known in the
state capital GIS data, such that an urban planner in San Diego could refer to
box ID 100, and it is the same grid cell as a planner in San Francisco would
see.</p><p><br></p><p>This project resulted in five primary result tables,
covering the five major urban centers of California:</p><p><br></p><p>
http://blog.light42.com/wordpress/?p=1439</p><p><br></p><p>You can see an
example of the SQL here, and in other posts:</p><p><br></p><p>
http://blog.light42.com/wordpress/?p=1489</p><p><br></p><p>The study has since
changed contents, but continues to this day, based here in
Berkeley</p><p><br></p><p>--</p><p>Brian M Hamlin</p><p>OSGeo California
Chapter</p><p>blog.light42.com</p><p><br></p><p><br></p><p><br></p><p>On Wed, 21
May 2014 17:12:50 +0400, Alexander Korotkov <aekorotkov@gmail.com>
wrote:<br></p><blockquote dir="ltr" style="border-left: 2px solid rgb(0, 0, 0);
padding-right: 0px; padding-left: 5px; margin-left: 5px; margin-right: 0px;"
_mce_style="border-left: 2px solid #000000; padding-right: 0px; padding-left:
5px; margin-left: 5px; margin-right: 0px;"><div id="html-message"><div
dir="ltr"><div class="gmail_extra"><div class="gmail_quote">On Wed, May 21, 2014
at 1:02 PM, Jeremy Palmer <span dir="ltr"><<a
href="mailto:JPalmer@linz.govt.nz"
target="_blank">JPalmer@linz.govt.nz</a>></span> wrote:<br><blockquote
class="gmail_quote" style="margin:0px 0px 0px
0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"
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border-left-color: #cccccc; border-left-style: solid; padding-left: 1ex;">
<div link="blue" vlink="purple" lang="EN-NZ">
<div>
<p class="MsoNormal">Hi PostGIS Devs,<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">I have a daily process that I would like to optimise. The
process includes a spatial intersects join between a small administration
boundaries table for New Zealand that contains large geometries (100,000+ points
per polygon) and a large
dataset with small line strings.<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">The first iteration of SQL I developed for the process I
used standard join (WHERE ST_Interesects(admin.geom, other.geom)) and it took 4
hours to complete. No spatial index was used. Not acceptable.</p>
</div></div></blockquote><div><br></div><div>So, your task is so-called "spatial
join". We are now doing researches on it. It would be nice if you could share
your dataset so we can do experiments on it. <br></div>
<div><br></div>------<br>With best regards,<br>Alexander
Korotkov.</div><br></div></div>
</div>
<br><hr><br>
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