[postgis-users] Returning contiguous linestrings

Bob Pawley rjpawley at shaw.ca
Wed Apr 18 03:57:52 PDT 2012

Hi Nicolas

I have, lets say, eight rows each containing a linestring, that, when put 
together forms a closed shape or polygon.

I can fairly easily detect one of the linestrings in this polygon.

Since each linestring has a endpoint at (or near) the startpoint of the next 
linestring in the polygon, I am wondering if there is a method of detecting 
the other linestrings, that forms a closed polygon, from that one contact.

>From this I would compare the shape to known shapes to identify it.

I have some ideas on how to possibly do this, but, I would rather not invent 
a function if a suitable one already exists.


-----Original Message----- 
From: Nicolas Ribot
Sent: Wednesday, April 18, 2012 1:03 AM
To: PostGIS Users Discussion
Subject: Re: [postgis-users] Returning contiguous linestrings

On 17 April 2012 19:21, Bob Pawley <rjpawley at shaw.ca> wrote:
> Hi
> I have a polygon shape composed of contiguous linestrings inhabiting
> different rows.
> Is there a fairly direct procedure for returning the polygon after 
> detecting
> a single linestring??
> Bob

Hi Bob,

Could you explain a bit further what you want to do, I don't understand.

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