Re: query question really cant give a summary here so read the body ;-)

["Rhys Stewart" <rhys.stewart@xxxxxxxxx>]

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 <cww@xxxxxxxxxxxxxxxx> 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