Yes, PostGIS LINESTRINGS, no not ST_AsEWKT(). By similar configuration I mean shape. So I can identify two lines if they have a similar shape. No not ST_Distance()....and don't call me Shirley.
I also neglected to include the query in my previous post. SELECT a.id,b.id FROM subsumed_secondary a INNER JOIN subsumed_secondary b ON a.geom && b.geom AND a.id <> b.id WHERE dev.line_descriptor_2(simplify(a.geom,1.5)) = dev.line_descriptor_2(simplify(b.geom,1.5)) On Fri, Apr 25, 2008 at 12:07 PM, Colin Wetherbee <[EMAIL PROTECTED]> wrote: > Rhys Stewart wrote: > >> The example I provided earlier was a very simplified model of the table >> I'm working with after a self join. The table in question contains >> geographic data (linestrings) >> > > PostGIS LINESTRINGs? > > > > and I have written a function to return a > >> textual representation >> > > Like ST_AsEWKT()? > > > so that I can easily identify lines with similar > >> configuration. I want to now select lines that are in close proximity to >> each other and have the same configuration. So this requires a self join >> (afaik). So, short of a function like the one that was posited earlier, is >> there a method using just plain old sql to get the results I desire? >> > > Surely, you don't mean ST_Distance()? > > What do you mean by "similar configuration"? > > Colin >