[postgis-users] polygons to linestrings

[Roxanne Reid-Bennett]

On 5/22/2014 12:28 PM, Richard Greenwood wrote:
> I have a polygon table that I want to convert to linestrings without 
> any duplicated (overlapping) linestrings. I'm doing this simply to 
> improve cartography so I'm looking for a quick and dirty approach, 
> avoiding topology if possible.

I'm not sure I understand what it is you are attempting to do from this 
description.  I would expect lines going in two directions from each 
polygon and I just don't know how you would use that to help with 
"improve cartography".
>
> The closest I've gotten so far is to break the polygons boundaries 
> into simple (two vertex) lines and delete all the duplicate lines. Now 
> I'm stuck getting the simple lines back into polylines. Just doing a 
> union of the whole mess isn't getting me individual linestrings.
So, crazy "out of the blue" question.. have  you considered creating a 
line (or lines) from the centroids?
>
> All this is turning into more steps that I anticipated and I wonder if 
> I'm missing simpler approach?
Or maybe describe what your target is?  There are a lot of people a lot 
more knowledgeable than I on this list, and if they haven't answered, 
perhaps you haven't presented your challenge in a manner that they can 
address.

Roxanne
>
> Thanks,
> Rich
>
> -- 
> Richard W. Greenwood, PLS
> www.greenwoodmap.com <http://www.greenwoodmap.com>
>
>
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