I don't quite understand your question. Are you trying to get the length of the intersection of the 2? So that part of the network component that falls within the quay?
In that case it would be something of the form SELECT ST_Length(ST_Intersection(netcomponent.the_geom, quay.the_geom)) Which assumes your netcomponent is defined as a LINESTRING (you can use ST_MakeLine http://postgis.refractions.net/documentation/manual-svn/ST_MakeLine.html if you have 2 points and no line) And quay is some sort of polygon. Hope that helps, Regina -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of [email protected] Sent: Saturday, February 14, 2009 11:31 AM To: [email protected] Cc: [email protected] Subject: [postgis-users] Which postGIS functions to use? I have a "network component" (= part of a waterway) defined by 2 coordinates. I know how to calculate the length of that component. However, another component, let's say a quay, overlaps with the component. I know how far it overlaps (in meters) with the component from the beginning coordinate and I want to calculate the end coordinate of the quay (that should be on the network component). How do I do this? Thank you _______________________________________________ postgis-users mailing list [email protected] http://postgis.refractions.net/mailman/listinfo/postgis-users _______________________________________________ postgis-users mailing list [email protected] http://postgis.refractions.net/mailman/listinfo/postgis-users
