Hello,<br><br>Maybe this post from Paul Ramsey can help you a bit e.g <a href="http://blog.cleverelephant.ca/2010/07/network-walking-in-postgis.html">http://blog.cleverelephant.ca/2010/07/network-walking-in-postgis.html</a><br>

<br>Regards<br><br>ThomasG<br>GIS specialist