<html><head><style>body{font-family:Helvetica,Arial;font-size:13px}</style></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;"><div id="bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px; color: rgba(0,0,0,1.0); margin: 0px; line-height: auto;">Do we want to go the “Accum” naming route, or introduce a “cluster” work?</div><div id="bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px; color: rgba(0,0,0,1.0); margin: 0px; line-height: auto;"><br></div><div id="bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px; color: rgba(0,0,0,1.0); margin: 0px; line-height: auto;"><span style="font-family: monospace;">ST_ClusterWithinDistance</span></div> <div id="bloop_sign_1421360500968449024" class="bloop_sign">
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<div>
<br>
</div><div>Also, since the intersecting cluster is just the withindistance with a tolerance of zero, would having just one function be good or bad?</div><div><br></div><div>P.</div><div><br></div>
-- <br>
Paul Ramsey<br>
http://cleverelephant.ca<div>http://postgis.net
</div>
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</div> <br><p style="color:#000;">On January 15, 2015 at 2:07:24 PM, Daniel Baston (<a href="mailto:dbaston@gmail.com">dbaston@gmail.com</a>) wrote:</p> <blockquote type="cite" class="clean_bq"><span><div><div></div><div>
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<div dir="ltr">Glad to hear there is some interest! I posted
some ideas to <a href="http://trac.osgeo.org/postgis/wiki/DevClusteringFunctions">http://trac.osgeo.org/postgis/wiki/DevClusteringFunctions</a>
<div><br></div>
<div>Thanks,</div>
<div>Dan</div>
</div>
<div class="gmail_extra"><br>
<div class="gmail_quote">On Thu, Jan 15, 2015 at 12:28 PM, Paul
Ramsey <span dir="ltr"><<a href="mailto:pramsey@cleverelephant.ca" target="_blank">pramsey@cleverelephant.ca</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div style="word-wrap:break-word">
<div style="font-family:Helvetica,Arial;font-size:13px;color:rgba(0,0,0,1.0);margin:0px;line-height:auto">
Daniel,</div>
<div style="font-family:Helvetica,Arial;font-size:13px;color:rgba(0,0,0,1.0);margin:0px;line-height:auto">
This is interesting stuff, could you post some example function
signature and input/output pictures on the wiki so we can do a
little design review. I thing it’s very exciting and am very
positive about it.</div>
<div style="font-family:Helvetica,Arial;font-size:13px;color:rgba(0,0,0,1.0);margin:0px;line-height:auto">
<span class="HOEnZb"><font color="#888888"><br></font></span></div>
<div style="font-family:Helvetica,Arial;font-size:13px;color:rgba(0,0,0,1.0);margin:0px;line-height:auto">
<span class="HOEnZb"><font color="#888888">P</font></span></div>
<div>
<div><span class="HOEnZb"><font color="#888888"><br></font></span></div>
<span class="HOEnZb"><font color="#888888">-- <br>
Paul Ramsey<br>
<a href="http://cleverelephant.ca" target="_blank">http://cleverelephant.ca</a></font></span>
<div><span class="HOEnZb"><font color="#888888"><a href="http://postgis.net" target="_blank">http://postgis.net</a></font></span></div>
</div>
<div>
<div class="h5"><br>
<p style="color:#000">On January 15, 2015 at 4:14:44 AM, Daniel
Baston (<a href="mailto:dbaston@gmail.com" target="_blank">dbaston@gmail.com</a>) wrote:</p>
</div>
</div>
<blockquote type="cite">
<div>
<div>
<div>
<div class="h5">
<div dir="ltr">
<div>
<div>
<div>
<div><span>Hello,<br>
<br>
I'm working on a couple of C-language functions to solve some
clustering problems I frequently face in PostGIS. I'm
wondering if there may be any level of interest in including such
functions in the project? I would be happy to flesh these out
to include the error-handling and unit-testing that would be
required.<br>
<br></span></div>
<span>Function #1 takes a GeometryCollection and returns the same
geometries, re-aggregated into groups of interconnected geometries
(solving a question I posted about at <a href="http://gis.stackexchange.com/q/94203" target="_blank">http://gis.stackexchange.com/q/94203</a> )<br>
<br></span></div>
<div><span>(Internally this builds an STRtree using GEOS and uses a
union-find structure to identify connected components....as an
aside, I am wondering if there is some way to take advantage of a
database spatial index that may already exist)<br></span></div>
<div><span><br></span></div>
</div>
<span>Function #2 (not written) would solve a related problem - we
want to take a set of points and return a set of MultiPoints, where
each point in a MultiPoint is within distance X of some other point
in the MultiPoint.<br>
<br></span></div>
<span>Thanks,<br>
Dan<br></span></div>
</div>
</div>
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</blockquote>
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