Hello,<br><br>I suppose it's similar to Postgis I know better. See this old post <a href="http://www.davidgis.fr/blog/index.php?2007/05/11">http://www.davidgis.fr/blog/index.php?2007/05/11</a> to understand.<br>It seems to be related to <a class="ext-link" href="http://www.opengeospatial.org/standards/sfs">OpenGIS Simple Features for SQL</a><br>
<br>Regards<br><br>ThomasG<br>GIS specialist<br>