<html><body><div style="color:#000; background-color:#fff; font-family:times new roman, new york, times, serif;font-size:12pt"><div><span>Thank you. Nicolas! Your explanations and sql example help a lot.</span></div><div><br><span></span></div><div><span>Greg<br></span></div><div><br></div> <div style="font-family: times new roman, new york, times, serif; font-size: 12pt;"> <div style="font-family: times new roman, new york, times, serif; font-size: 12pt;"> <div dir="ltr"> <font size="2" face="Arial"> <hr size="1"> <b><span style="font-weight:bold;">From:</span></b> Nicolas Ribot <nicolas.ribot@gmail.com><br> <b><span style="font-weight: bold;">To:</span></b> PostGIS Users Discussion <postgis-users@postgis.refractions.net> <br> <b><span style="font-weight: bold;">Sent:</span></b> Monday, June 18, 2012 4:31 PM<br> <b><span style="font-weight: bold;">Subject:</span></b> Re: [postgis-users] snapping all close-by lines in a set of 500, 000<br>
</font> </div> <br><div id="yiv950267009">I find useful to explode a linestring into its points to be able to identify pseudo-parallel lines: st_distance is not enough as perpendicular, touching lines will return 0 for the distance though they are not close to each other at each location.<br>
If all linestring points are within a given distance to a line, then chances are good these 2 lines are aligned.<br><div>...<br>Nicolas </div>
</div><meta http-equiv="x-dns-prefetch-control" content="on"><br>_______________________________________________<br>postgis-users mailing list<br><a ymailto="mailto:postgis-users@postgis.refractions.net" href="mailto:postgis-users@postgis.refractions.net">postgis-users@postgis.refractions.net</a><br><a href="http://postgis.refractions.net/mailman/listinfo/postgis-users" target="_blank">http://postgis.refractions.net/mailman/listinfo/postgis-users</a><br><br><br> </div> </div> </div></body></html>