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<DIV dir=ltr align=left><SPAN class=826515923-02052008><FONT face=Arial
color=#0000ff size=2>If two geometries overlap, which one would you take?
I assume you would leave all out of an overlapping set except for one or would
you be taking the non-overlapping sections? </FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=826515923-02052008><FONT face=Arial
color=#0000ff size=2></FONT></SPAN> </DIV>
<DIV dir=ltr align=left><SPAN class=826515923-02052008><FONT face=Arial
color=#0000ff size=2>Thanks,</FONT></SPAN></DIV>
<DIV dir=ltr align=left><SPAN class=826515923-02052008><FONT face=Arial
color=#0000ff size=2>Regina</FONT></SPAN></DIV><BR>
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<FONT face=Tahoma size=2><B>From:</B>
postgis-users-bounces@postgis.refractions.net
[mailto:postgis-users-bounces@postgis.refractions.net] <B>On Behalf Of </B>Dylan
Lorimer<BR><B>Sent:</B> Friday, May 02, 2008 7:29 PM<BR><B>To:</B> PostGIS Users
Discussion<BR><B>Subject:</B> [postgis-users] Unique
Coverage<BR></FONT><BR></DIV>
<DIV></DIV>Hi PostGIS Users,<BR><BR>Have what I hope is a simple problem that
I'm not sure how to solve with PostGIS. I think I need to do a self-join on 0
overlap, but I'm just not certain.<BR><BR>Given a number of polygons, some
overlapping, some not, I want to produce the geometries of all non-overlapping
areas...ie all unique "pixels". This has specifically to do with catalogs of
overlapping imagery over an area, where I have polygons for each scene and want
to compute unique pixels. <BR><BR>Would I join a table with itself to achieve
this?<BR clear=all><BR>Cheers,<BR>dylan<BR></BODY></HTML>