[postgis-users] Difference polygon sets

[Pedro Monteiro]

Sory, the previous post was not to this list.

2010/8/27 Espen Isaksen <espen.isaksen at gmail.com>

> Hi!
>
> I have a set of polygons where I have dissolved some of the polygons.
> So I get two sets of polygons where one set is my original data, and
> the other set is new polygons from the dissolve operations. Now I want
> to extract the remaining polygons from my original dataset which were
> not dissolved. I tried just a simple st_difference, but from what I
> understand this operation does now work on sets of polygons.
>
> Both datasets can be found here in shape format:
> http://dl.dropbox.com/u/8829/postgis.zip
>
> How can I extract only the remaining polygons from the original
> dataset. I had a look at this
> post(http://www.postgis.org/pipermail/postgis-users/2008-May/019511.html)
> in the mailing list, but I did not succeed in changing it to fit my
> purpose.
>
> Can anybody help me out?
>
> Kind regards,
> Espen Isaksen
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