<div dir="ltr"><div><div><div><div><div><div>Your querry doesn't handle properly the case when one line has to be split by multiple other lines.<br><br></div>a simple list<br></div>_are the geom valid (ST_ISValid / ST_MakeValid)<br></div>_are the geom in the same referential<br></div>_do you have a recent postgis/geos version (postgis_full_version())<br></div>_are you geometry at the correct precision (st_snaptogrid())<br>...<br></div>Cheers,<br>Rémi-C<br></div><div class="gmail_extra"><br><div class="gmail_quote">2014-10-17 22:23 GMT+02:00  <span dir="ltr"><<a href="mailto:Alexander.Mahrou@ch2m.com" target="_blank">Alexander.Mahrou@ch2m.com</a>></span>:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">





<div link="#0563C1" vlink="#954F72" lang="EN-US">
<div>
<p class="MsoNormal">Hello List, <u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">I’ve got two polyline tables. I’m attempting to segment my lines by the intersections of the other lines.
<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">create table segments as SELECT ST_CollectionExtract(ST_Split(a.newgeom,b.geom),2) as geom from<u></u><u></u></p>
<p class="MsoNormal">                line1 a, line2 b WHERE ST_Intersects(a.newgeom,b.geom) = true<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal">The end result is the geometry that I started with. What am I doing wrong?<u></u><u></u></p>
<p class="MsoNormal"><u></u> <u></u></p>
<p class="MsoNormal" style="margin-left:2.0pt;line-height:8.15pt;text-autospace:none">
<b><span style="font-size:8.0pt;font-family:"Arial","sans-serif";color:#656565;letter-spacing:-.05pt">Alex Mahrou</span></b><span style="font-size:8.0pt;font-family:"Arial","sans-serif";color:black"><u></u><u></u></span></p>
<p class="MsoNormal" style="margin-left:2.0pt;text-autospace:none">
<i><span style="font-size:8.0pt;font-family:"Arial","sans-serif";color:#656565">Oil, Gas & Chemicals<u></u><u></u></span></i></p>
<p class="MsoNormal" style="margin-top:1.0pt;line-height:11.0pt;text-autospace:none">
<span style="font-family:"Times New Roman","serif";color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><b><span style="font-size:8.0pt;font-family:"Arial","sans-serif";color:#656565;letter-spacing:-.05pt">CH2</span></b><b><span style="font-size:8.0pt;font-family:"Arial","sans-serif";color:#656565">M<span style="letter-spacing:-.5pt">
</span><span style="letter-spacing:-.05pt">H</span><span style="letter-spacing:.05pt">I</span><span style="letter-spacing:-.05pt">LL<u></u><u></u></span></span></b></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:8.0pt;font-family:"Arial","sans-serif";color:#656565;letter-spacing:-.05pt">9191 S. Jamaica St.<u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:8.0pt;font-family:"Arial","sans-serif";color:#656565;letter-spacing:-.05pt">Englewood, CO 80112<u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:8.0pt;font-family:"Arial","sans-serif";color:#656565;letter-spacing:-.05pt"><a href="http://www.ch2m.com" target="_blank">www.ch2m.com</a></span><span style="font-size:8.0pt;font-family:"Arial","sans-serif";color:black"><u></u><u></u></span></p>
<p class="MsoNormal"><u></u> <u></u></p>
</div>
</div>

<br>_______________________________________________<br>
postgis-users mailing list<br>
<a href="mailto:postgis-users@lists.osgeo.org">postgis-users@lists.osgeo.org</a><br>
<a href="http://lists.osgeo.org/cgi-bin/mailman/listinfo/postgis-users" target="_blank">http://lists.osgeo.org/cgi-bin/mailman/listinfo/postgis-users</a><br></blockquote></div><br></div>